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1: Tube DIY Asylum, RE: Do you think 6CG7 can run 1mA having the lowest distortion ? (0.00)
Posted by Triode_Kingdom on 2024-04-24, 22:33:53 (24.27.41.140)
Eric, I have never operated a 6CG7 or 6SN7 at such a low plate voltage. This is an area of the curves that might exhibit a greater variation from tube to tube than operation at higher voltages and cur .......
2: Tube DIY Asylum, RE: Do you think 6CG7 can run 1mA having the lowest distortion ? (0.00)
Posted by Triode_Kingdom on 2024-04-24, 07:13:47 (24.27.41.140)
1mA is near the sweet spot of the curves at that anode voltage. THD improves if standing current is increased to 1.5mA. This all changes if the tube is operated at 200V, where 1mA = 0.1% and 5mA = 0.0 .......
3: Tube DIY Asylum, RE: Agree (0.00)
Posted by Triode_Kingdom on 2024-04-21, 23:46:19 (24.27.41.140)
Elevating the heater resolves that issue. .......
4: Vinyl Asylum, Yay! (0.00)
Posted by Triode_Kingdom on 2024-04-20, 08:01:13 (24.27.41.140)
I'm embarrassed to say I didn't know about this. As in - never heard of it. Shame on me. Looks like the first RSD was on my birthday in 2008. Must be an omen. Going to the local RS later today. Thanks .......
5: Tubes Asylum, Almost but Not Quite the Same (0.00)
Posted by Triode_Kingdom on 2024-04-19, 14:13:30 (24.27.41.140)
I'm sure the 6L6WGB and 5881 are interchangeable in many situations. However, the screen rating for the 6L6WGB is 300V, whereas it's 400V for both screen and anode in the 5881. So, almost the same, bu .......
6: Vintage Asylum, RE: DRA-700 ? (0.00)
Posted by Triode_Kingdom on 2024-04-18, 20:51:52 (24.27.41.140)
"I've ordered a button cell battery holder that I'll solder in place here, so replacing the battery won't be such a hassle in the future." Funny, I did that last year for my lawn sprinkler system. The .......
7: Tube DIY Asylum, Agree (0.00)
Posted by Triode_Kingdom on 2024-04-18, 20:48:58 (24.27.41.140)
You can't beat a quality cap and simple resistor for a Class A stage like this. .......
8: Vintage Asylum, RE: DRA-700 ? (0.00)
Posted by Triode_Kingdom on 2024-04-17, 23:41:09 (24.27.41.140)
That's interesting. The manual I found is for the DRA-700AE, DRA-700AEDAB and DRA-500AE. I spent over an hour searching the schematics and parts lists for a supercap, a battery, or anything similar. N .......
9: Vintage Asylum, DRA-700 ? (0.00)
Posted by Triode_Kingdom on 2024-04-17, 19:32:58 (24.27.41.140)
Are you sure this is a DRA-700. One of the photos you posted includes a small inline IC labeled IC505. However, the DRA-700 manual that I located online shows IC505 to be a three-terminal device attac .......
10: Vintage Asylum, RE: Denon DRA-700 Backup battery (0.00)
Posted by Triode_Kingdom on 2024-04-17, 07:17:19 (24.27.41.140)
I would be surprised if that's actually a battery. Units I'm familiar with use a "super capacitor" for memory voltage. Google this and you'll see various styles. Can you post a photo showing the physi .......
11: Tube DIY Asylum, Glad it's fixed! (0.00)
Posted by Triode_Kingdom on 2024-04-17, 06:04:48 (24.27.41.140)
These types of problems drive me nuts sometimes. It's just so easy to overlook the obvious, especially when working with all these vintage parts. Glad to hear it was easy to resolve! .......
12: Tube DIY Asylum, RE: Help with 6SL7 tube curves (0.00)
Posted by Triode_Kingdom on 2024-04-16, 13:51:50 (24.27.41.140)
There are only a few possibilities. The tube might be defective, or this could be a measurement error. .......
13: Headphone Heights, Did you mean high sensitivity?` (0.00)
Posted by Triode_Kingdom on 2024-04-14, 21:02:37 (24.27.41.140)
My Grado SR60i phones are very sensitive. The specification is 98dB/1mW, and I think that's conservative. In my recent bench tests at 400Hz, anything above 20mV RMS was LOUD . That would be equivalent .......
14: Tube DIY Asylum, RE: Direct-cupled DHSET can be tricky (0.00)
Posted by Triode_Kingdom on 2024-04-13, 15:38:40 (24.27.41.140)
My 211 SETs use a choke-loaded IDHT follower direct-coupled to the output stage grid. Despite powering the driver from its own power supplies, there was significant drift of output stage idle current .......
15: Tubes Asylum, RE: Some claim to be able to test for "noise" (0.00)
Posted by Triode_Kingdom on 2024-04-12, 20:13:51 (24.27.41.140)
I don't own a TV-7, so I never noticed that feature. Like you say, it might only detect tubes that are so noisy, it would be the result of a broken internal support or internal arcing. An AM radio isn .......
16: Tube DIY Asylum, RE: So, would u view DHT's any differently? (0.00)
Posted by Triode_Kingdom on 2024-04-12, 20:02:20 (24.27.41.140)
I might need to defer to the opinions of others on that point, because I don't have long-term experience with all the various tube types or different operating voltages. However, my 211 SETs use a sup .......
17: Tube DIY Asylum, RE: Need for Soft-Start / Standby for Solid State Rectification? (0.00)
Posted by Triode_Kingdom on 2024-04-12, 12:34:07 (24.27.41.140)
It's an urban myth propagated by people who don't know better. The voltages present in receivers and most amplifiers aren't sufficient to damage the tubes. The only real concerns are A) negative bias .......
18: Tube DIY Asylum, RE: DN2540 CCS, cascade or not cascade, what you prefer? (0.00)
Posted by Triode_Kingdom on 2024-04-11, 18:45:35 (24.27.41.140)
"But regardless of the duration of the non-linearity, that non-linearity would have to substantially lower the impedance of the CCS or it won't make an audible difference." No one knows how much (or w .......
19: Tube DIY Asylum, Again - Chokes Introduce Energy Storage (0.00)
Posted by Triode_Kingdom on 2024-04-11, 13:48:24 (24.27.41.140)
This increases dynamic headroom. The sonic benefits are apparent also in cathode followers. .......
20: Tube DIY Asylum, RE: DN2540 CCS, cascade or not cascade, what you prefer? (0.00)
Posted by Triode_Kingdom on 2024-04-11, 13:42:42 (24.27.41.140)
"The CCS is such a high impedance vs. the plate resistance of the triode that it is loading that the non-linearity of the device will have very little influence over the total. A tiny fraction." You c .......
21: SET Asylum, RE: Has Any One Tried This??! (0.00)
Posted by Triode_Kingdom on 2024-04-11, 07:41:39 (24.27.41.140)
That's an interesting approach, and not too difficult to implement. I do wish the article included measurements to confirm the claims of improved performance. An EF86 in triode mode driving a typical .......
22: Tube DIY Asylum, RE: "a thumb drive velcro'd to the rear panel" (0.00)
Posted by Triode_Kingdom on 2024-04-11, 07:24:32 (24.27.41.140)
I haven't seen any evidence that the levels of magnetic fields present around amplifiers can affect these devices. Bear in mind, I consider this to be a backup, something to be used if the hardcopy is .......
23: Tube DIY Asylum, RE: DN2540 CCS, cascade or not cascade, what you prefer? (0.00)
Posted by Triode_Kingdom on 2024-04-11, 07:05:51 (24.27.41.140)
"CCS provide 100M ohm load resistance that no real choke could" Resistance measurements don't communicate the non-linear idiosyncrasies of the SS junction within the device. In addition, a choke can s .......
24: Tube DIY Asylum, I Prefer no Semiconductors (0.00)
Posted by Triode_Kingdom on 2024-04-10, 21:57:37 (24.27.41.140)
If I wanted semiconductors attached to the signal path, I wouldn't be working with tubes. That aside, this is excellent info to have when a CCS is needed for other purposes, such as test equipment. : .......
25: Tube DIY Asylum, That Info Readily Available in the Published Curves (0.00)
Posted by Triode_Kingdom on 2024-04-09, 16:23:45 (24.27.41.140)
So many variables, including screen voltage. You'll get a better idea of what's needed if you study the curves for yourself. Triode curves are useful if the amp will be UL (same voltage screen and ano .......
26: Tube DIY Asylum, RE: DIY Lettering For Chassis. (0.00)
Posted by Triode_Kingdom on 2024-04-09, 14:29:41 (24.27.41.140)
Looks great by the way! .......
27: Tube DIY Asylum, RE: DIY Lettering For Chassis. (0.00)
Posted by Triode_Kingdom on 2024-04-09, 14:29:04 (24.27.41.140)
Everyone where I live has minimums. Do you know how much that service would have charged for a quantity of one? .......
28: Vinyl Asylum, No reason to insult anyone (0.00)
Posted by Triode_Kingdom on 2024-04-07, 19:26:38 (24.27.41.140)
I was designing and building hi-fi gear before most people on these forums were born, and I know exactly what a clean LP sounds like. This obsession over record cleaning is only in vogue because so ma .......
29: Vinyl Asylum, So it's come to this (0.00)
Posted by Triode_Kingdom on 2024-04-07, 08:13:15 (24.27.41.140)
How to waste the most money possible cleaning records. As if none of us knew how to use vinyl in the '70s and '80s. Very sad. .......
30: Vintage Asylum, RE: Pioneer H-Z1 capacitor covered by crystals (0.00)
Posted by Triode_Kingdom on 2024-04-06, 23:14:32 (24.27.41.140)
A photo would help. .......
31: Vinyl Asylum, Yep, that's pretty bad writing (0.00)
Posted by Triode_Kingdom on 2024-04-06, 15:23:21 (24.27.41.140)
That's what happens when you fail to not employ an amateur technical writer. .......
32: Tube DIY Asylum, Schematics (0.00)
Posted by Triode_Kingdom on 2024-04-01, 20:11:17 (24.27.41.140)
"I am thinking of transferring a schematic of each of my amps etc to a PCB" I will soon be writing schematics, instructions, parts lists etc. for each of my units onto a thumb drive velcro'd to the re .......
33: Tube DIY Asylum, RE: DIY Lettering For Chassis. (0.00)
Posted by Triode_Kingdom on 2024-03-31, 20:58:23 (24.27.41.140)
Back in the day, we used DATAK dry transfer lettering, then sprayed it with a thin coat of Krylon clear. The letter/number sheets were available in black or white. I don't know another cost effective .......
34: Tube DIY Asylum, Agree (nt) (0.00)
Posted by Triode_Kingdom on 2024-03-30, 18:25:15 (24.27.41.140)
nada aqui .......
35: Tube DIY Asylum, But not all, and even the energy above 20kHz is too close (0.00)
Posted by Triode_Kingdom on 2024-03-30, 18:24:38 (24.27.41.140)
So it mixes with the desired signals to create random IM distortion all through the audio band. Shielding and filtering are usually both required to resolve this problem. .......
36: Tube DIY Asylum, Well, no... (0.00)
Posted by Triode_Kingdom on 2024-03-29, 17:17:58 (24.27.41.140)
The DC output of these regulated supplies is very dirty. Check with a scope, and you'll see it. There may be exceptions that have more rigorous internal filtering, but they're few and far between. :: .......
37: Tube DIY Asylum, My Solution (0.00)
Posted by Triode_Kingdom on 2024-03-29, 10:04:26 (24.27.41.140)
"I tried a Mean Well SMPS into Rod Coleman regs and it sounded very much worse than a proper linear supply. Unusable by my standards." That's interesting. I've analyzed the output of several SMPS modu .......
38: Tube DIY Asylum, Yessir, it does! (0.00)
Posted by Triode_Kingdom on 2024-03-28, 15:23:53 (24.27.41.140)
"Doesn't a SMPS throw a lot of RF into the surrounding environment?" A regulated SMPS emits a nasty mix of frequencies that are constantly modulated over a very wide range. They're simply not suitable .......
39: Vinyl Asylum, RE: Vinyl Outsells CDs again (0.00)
Posted by Triode_Kingdom on 2024-03-27, 07:19:30 (24.27.41.140)
"I don't have a single friend under 40 that doesn't own a turntable audiophile or not." My daughter is 20. She doesn't own a turntable, nor do any of her many, many friends. While she recognizes that .......
40: Vinyl Asylum, RE: Vinyl Outsells CDs again (0.00)
Posted by Triode_Kingdom on 2024-03-26, 22:49:01 (24.27.41.140)
Sadly, much of the younger generation has moved to streaming. Throw that into the mix, and I think we won't find LP sales anything to brag about. .......
41: Vinyl Asylum, Powerful People (0.00)
Posted by Triode_Kingdom on 2024-03-26, 22:44:22 (24.27.41.140)
The title song of "Powerful People" is also on the "Best of" album. It's a really excellent selection of his art: Wheels Of Life Crazy Life I Just Wanna Stop Love Me Now Powerful People People Gotta M .......
42: Tube DIY Asylum, Never seen that (0.00)
Posted by Triode_Kingdom on 2024-03-26, 15:17:40 (24.27.41.140)
My 211 monos sound pretty damn good right off the bat. I did have an issue with bias drift at first (direct coupled driver), but I designed an auto-bias circuit that resolved that. Even before this "f .......
43: Vinyl Asylum, RE: I went down a rabbit hole (0.00)
Posted by Triode_Kingdom on 2024-03-24, 20:21:54 (24.27.41.140)
I'm afraid the same thing is about to happen here. We have a local new/used LP outlet with hundreds of albums I'd love to own. The prices are outrageous though, so I'll probably have to 2nd mortgage t .......
44: Vinyl Asylum, RE: Spinning: Gino Vannelli " Brother To Brother. (0.00)
Posted by Triode_Kingdom on 2024-03-23, 20:30:56 (24.27.41.140)
Wasn't aware of his artistry until '82 or so when I bought the "Best of" album. It includes the title song of your disc. Amazingly dynamic, I listened to it just a couple days ago. .......
45: Headphone Heights, RE: RAAL-Requisite SR1B Ribbon Headphones (0.00)
Posted by Triode_Kingdom on 2024-03-23, 15:36:27 (24.27.41.140)
Stereophile reviews haven't been credible for decades. .......
46: Tubes Asylum, RE: Is Cr13n a direct replacment for 0A2? (0.00)
Posted by Triode_Kingdom on 2024-03-22, 13:30:11 (24.27.41.140)
That sounds as though the tube might have been arcing internally. I've seen them do that, although it's not too common. Glad it's all good now. :) .......
47: Tubes Asylum, RE: Is Cr13n a direct replacment for 0A2? (0.00)
Posted by Triode_Kingdom on 2024-03-21, 15:10:23 (24.27.41.140)
In that case, I would expect the new 0A2 to also last a long time. Sounds like you have plenty of spares now. :) Out of curiosity, what was the failure mode? Did it stop striking? .......
48: Tubes Asylum, RE: Is Cr13n a direct replacment for 0A2? (0.00)
Posted by Triode_Kingdom on 2024-03-20, 23:53:28 (24.27.41.140)
I wouldn't think there would be a benefit unless the OA2s are failing. Gas regulators usually last many years if the equipment is properly designed. .......
49: Vintage Asylum, RE: Ballantyne MX24D (0.00)
Posted by Triode_Kingdom on 2024-03-19, 07:51:22 (24.27.41.140)
Wow, those are some serious amplifiers! I had to look this up. Sorry I can't help with the schematic. Even the photos I found don't appear to show 7027 drivers. .......
50: Vintage Asylum, RE: Ballantyne MX24D (0.00)
Posted by Triode_Kingdom on 2024-03-18, 13:43:42 (24.27.41.140)
"7027A tubes before the output stage"? Wow, what are the outputs - 833? .......
51: Vintage Asylum, RE: Pioneer SX980 volume pot issue (0.00)
Posted by Triode_Kingdom on 2024-03-17, 08:36:40 (24.27.41.140)
Sometimes the allen screws create small dimples in the shaft. That can create resistance when trying to put the knob back on. You might need to remove the pot and smooth the defects with sandpaper if .......
52: Tube DIY Asylum, RE: The Issue with These Tubes is Distortion (0.00)
Posted by Triode_Kingdom on 2024-03-15, 15:07:17 (24.27.41.140)
"I also like the pretty glowing lights." I agree with you, THD isn't everything. However, the 829Bs I've tried don't even pass the "pretty glow" test. Some are difficult to even know if they're lit. T .......
53: Tube DIY Asylum, Yes but you can speed up the turntable to compensate (nt) (0.00)
Posted by Triode_Kingdom on 2024-03-15, 07:04:30 (24.27.41.140)
nada aqui .......
54: Tubes Asylum, RE: Tube hiss .and/or alignment? (0.00)
Posted by Triode_Kingdom on 2024-03-12, 08:35:50 (24.27.41.140)
It might be a noisy component (tube or resistor) in the audio chain after the detector. I would also want to use a scope to look at the IF signal levels. Full limiting is necessary for quiet reception .......
55: Tube DIY Asylum, Excess Gain (0.00)
Posted by Triode_Kingdom on 2024-03-08, 16:54:09 (24.27.41.140)
"I am interested what, if anything, was done to deal with the excess gain." This is something I've been dealing with in earnest recently. I recently reworked a Hafler preamp that's serving as backup w .......
56: Tube DIY Asylum, Apples and Oranges (0.00)
Posted by Triode_Kingdom on 2024-02-28, 05:59:02 (24.27.41.140)
The type of distortion involved is crucial to audibility, as is the spectral signature. It's generally recognized that speaker distortion is much less offensive than the various types of electrical di .......
57: Tube DIY Asylum, RE: What would you use to fill in the air gap of a SE OPT? (0.00)
Posted by Triode_Kingdom on 2024-02-27, 22:45:42 (24.27.41.140)
"even if precision ground the gap is still substantial" Exactly right. And closing it up magnetically is like trying to put Humpty Dumpty back together. :) .......
58: Tube DIY Asylum, RE: Is it a Bad Tube or a Bad fuse (Fuse Fatigue)? (0.00)
Posted by Triode_Kingdom on 2024-02-27, 13:12:38 (24.27.41.140)
Fuses don't fail if they're sized correctly. The value of that fuse indicates it might be in series with B+ to the output transformer. Given that the possibly bad tube(s) didn't cause a fuse to blow w .......
59: Tube DIY Asylum, RE: The Issue with These Tubes is Distortion (0.00)
Posted by Triode_Kingdom on 2024-02-27, 11:15:04 (24.27.41.140)
I've read that article before. It's heavily skewed by the author's attempt to prove THD numbers don't matter, and almost totally irrelevant in any attempt to prioritize Class A tube distortion. What I .......
60: Tube DIY Asylum, RE: The Issue with These Tubes is Distortion (0.00)
Posted by Triode_Kingdom on 2024-02-27, 10:50:34 (24.27.41.140)
The 829B is rated for 30W continuous anode dissipation with natural cooling, obviously much more than a 45 or 2A3. Pete's amplifier could output about 5W at clipping, so the 1% measurement represents .......
61: Tube DIY Asylum, The Issue with These Tubes is Distortion (0.00)
Posted by Triode_Kingdom on 2024-02-26, 13:32:30 (24.27.41.140)
This is unfortunately a high-distortion tube. Pete Millett used the 829B in his SET amplifier and measured almost 1% THD at 1W output. I understand the Cayin 500 line (PPP pentode-mode 829B) uses comp .......
62: Vinyl Asylum, RE: Grid stopper... (0.00)
Posted by Triode_Kingdom on 2024-02-25, 20:08:40 (24.27.41.140)
Grid stoppers should always be non-inductive, and that restricts them to carbon composition. All others are wound in a spiral. .......
63: Tubes Asylum, It Depends (0.00)
Posted by Triode_Kingdom on 2024-02-21, 13:52:07 (24.27.41.140)
Most audio tubes are relatively harmless. However, certain transmitting tetrodes use a piece of beryllium oxide on the outside of the tube to conduct heat directly from the anode. This material is haz .......
64: Tube DIY Asylum, Input isolation? (0.00)
Posted by Triode_Kingdom on 2024-02-20, 13:59:46 (24.27.41.140)
If the application doesn't require isolating the left and right signals from each other at the input of the combiner, just use a couple high value resistors like Chip647 suggested below. If it's neces .......
65: Vinyl Asylum, It's a beauty! (0.00)
Posted by Triode_Kingdom on 2024-02-19, 14:45:52 (24.27.41.140)
Love that SME arm too. Had one of those on a Michell Transcriptor in the mid-'70s. Also a beautiful combination, but in a different way. Don't know how I would ever choose between that one and the 301 .......
66: Tube DIY Asylum, Have you contacted this company? (0.00)
Posted by Triode_Kingdom on 2024-02-12, 23:10:08 (24.27.41.140)
I would try this company first. There's another company online selling Hickok meters, but they want $250 or more. If you really want a substitute, I would try eBay for a NOS meter rather than the Chin .......
67: Tube DIY Asylum, EL34 instead of a 6V6 (0.00)
Posted by Triode_Kingdom on 2024-02-09, 06:35:50 (24.27.41.140)
Highly unlikely, assuming the transformer was designed for a pair of 6V6 in class A or AB1. EL34s draw roughly twice the current or more, which means at least four times the loss (dissipation) in the .......
68: Vinyl Asylum, Any such process would create more problems than it solves (nt) (0.00)
Posted by Triode_Kingdom on 2024-02-07, 06:20:33 (24.27.41.140)
nada aqui .......
69: Vinyl Asylum, Agree! (nt) (0.00)
Posted by Triode_Kingdom on 2024-02-07, 01:53:27 (24.27.41.140)
nada aqui .......
70: Vinyl Asylum, RE: Vintage Idler Wow (0.00)
Posted by Triode_Kingdom on 2024-01-26, 01:14:32 (24.27.41.140)
Can you discern the approximate frequency of the wow? That might help to pinpoint whether it's the idler or the platter. You can calculate the rotational speed of the idler based on its diameter and t .......
71: Tube DIY Asylum, RE: The mark III uses tubes with heaters rather than filiment cathodes (0.00)
Posted by Triode_Kingdom on 2024-01-24, 22:34:18 (24.27.41.140)
"I like to force the heaters to around 40 volts to avoid any diode noise that might develop between the cathode and the heater. Hooking the center tap to a simple voltage divider off the B+ with a 1.0 .......
72: Tubes Asylum, RE: the more reading I do about tube testers (0.00)
Posted by Triode_Kingdom on 2024-01-23, 06:12:52 (24.27.41.140)
A complete test of power tubes needs to include measurements under actual operating conditions. For me, testing and matching is a two step process. First, I test and match the tubes for transconductan .......
73: Vinyl Asylum, RE: So I've read. (0.00)
Posted by Triode_Kingdom on 2024-01-21, 08:23:56 (24.27.41.140)
The primary risk occurs if the user plugs in the line cords, then makes audio connections. A large voltage can exist between the various chassis until the cable grounds connect everything together. Co .......
74: Vinyl Asylum, Mixed Grounds (0.00)
Posted by Triode_Kingdom on 2024-01-21, 07:19:29 (24.27.41.140)
It can be exceedingly dangerous to remove the safety ground connection from the chassis, particularly in tube gear. When a ground loop is "cured" this way, it means that one or more pieces in the syst .......
75: Tube DIY Asylum, RE: WL Laurel MB 300b cap info needed (0.00)
Posted by Triode_Kingdom on 2024-01-21, 07:09:18 (24.27.41.140)
Electrolytic capacitors are typically specified with a tolerance of +20%. This means the actual value of the 50uF replacements might or might not be greater than the originals. There won't be any sign .......
76: Vintage Asylum, RE: AR-3s need help (0.00)
Posted by Triode_Kingdom on 2024-01-17, 22:03:12 (24.27.41.140)
I took a quick look at your link just for old time's sake. I used to perform factory authorized service for AR back in the day. I don't remember seeing a lot of AR3s come in, but it wasn't unusual for .......
77: Tube DIY Asylum, RE: Done building (0.00)
Posted by Triode_Kingdom on 2024-01-16, 15:48:48 (24.27.41.140)
If you add your location to your AA profile, someone close by might be able to assist. .......
78: Tube DIY Asylum, RE: I'm using Sylvania 12sl7's and Russian 6V6's and it sounds better than I hoped it would (0.00)
Posted by Triode_Kingdom on 2024-01-16, 15:47:00 (24.27.41.140)
12V tubes are a boon to high quality DIY. My small SEP now uses 12V6 with a DC heater supply. The NOS Sylvania chrome domws I installed are really superb! .......
79: Tubes Asylum, Thank you! (nt) (0.00)
Posted by Triode_Kingdom on 2024-01-15, 13:51:12 (24.27.41.140)
nada aqui .......
80: Vintage Asylum, Funky Looking Component (0.00)
Posted by Triode_Kingdom on 2024-01-15, 07:09:10 (24.27.41.140)
The pictorial in the service manual refers to that as L7, a 100uH choke. However, the schematic denotes L7 as a 2.2uH choke. This part feeds DC tuning voltage to the FM oscillator varactors D1-4, so I .......
81: Tubes Asylum, Vita Circuitry (0.00)
Posted by Triode_Kingdom on 2024-01-15, 06:18:54 (24.27.41.140)
Can you describe this in more detail? I haven't heard of it previously. .......
82: Tubes Asylum, RE: Beautiful amp! (0.00)
Posted by Triode_Kingdom on 2024-01-14, 15:38:42 (24.27.41.140)
From what I see in the photo, build quality is very high. And I would expect those 100W OPTs to have a ton of headroom and bandwidth. I can see why it performs so well. Good luck again with the tubes! .......
83: Tube DIY Asylum, RE: yay!! I finally found the problem, thanks everybody (0.00)
Posted by Triode_Kingdom on 2024-01-14, 15:34:29 (24.27.41.140)
A bad or missing connection is almost always the cause of a newly built unit that doesn't work. That was true even with kits that came with detailed instructions and check boxes. I used to perform aut .......
84: Tubes Asylum, Beautiful amp! (0.00)
Posted by Triode_Kingdom on 2024-01-13, 14:20:14 (24.27.41.140)
Do you know anything about the transformers in this build? Would love to see the interior too if you have photos. Wish I could help regarding the tubes, but I probably don't have any resources you don .......
85: Tubes Asylum, RE: Vendor Recommendations for Sylvania 6L6GA JAN CHS (0.00)
Posted by Triode_Kingdom on 2024-01-13, 06:43:17 (24.27.41.140)
"My amp was custom designed specifically for the ST 6L6GA... and the Sylvania is the best sounding" I can't tell from your post whether you've actually tried the 6P3S-E. I have a large quantity of th .......
86: Tubes Asylum, RE: Vendor Recommendations for Sylvania 6L6GA JAN CHS (0.00)
Posted by Triode_Kingdom on 2024-01-12, 22:13:24 (24.27.41.140)
If an ST envelope isn't essential, the Russian 6P3S-E is a bargain. Used under operating conditions appropriate for the 6L6G or 6L6GA, it's very reliable and long lasting. .......
87: SET Asylum, RE: And then again, (0.00)
Posted by Triode_Kingdom on 2024-01-12, 22:03:23 (24.27.41.140)
At the risk of sounding immodest, I've been pleased with my own implementations of feedback in single-ended amps. It helps when the driver exhibits an abundance of headroom and good test equipment is .......
88: SET Asylum, Load Z (0.00)
Posted by Triode_Kingdom on 2024-01-12, 21:46:39 (24.27.41.140)
The operating point achieved with the low-Z primaries typically used for a 300B is optimized for output power. Linearity would improve considerably with a 6KΩ or higher load, but perhaps this isn't th .......
89: Tube DIY Asylum, The output stage needs it (0.00)
Posted by Triode_Kingdom on 2024-01-10, 05:33:25 (24.27.41.140)
I'm not familiar with that particular driver topology. However, IMD will be unacceptably high without a means of correcting the output stage. .......
90: Tube DIY Asylum, You are correct, Grasshopper :) (0.00)
Posted by Triode_Kingdom on 2024-01-08, 16:02:27 (24.27.41.140)
Maybe a chopstick and/or freeze spray would help to pinpoint it without a scope (or schematic). .......
91: Tube DIY Asylum, RE: I was looking for a schematic for an amp to speed things along with (0.00)
Posted by Triode_Kingdom on 2024-01-07, 08:33:07 (24.27.41.140)
There are a lot of junk schematics on the Internet. In this case, however, it doesn't look so bad. The 6SL7 cathode is biased through the 1KΩ FB resistor and output transformer winding to ground. I do .......
92: Vinyl Asylum, RE: SOTA Moonbeam VI (0.00)
Posted by Triode_Kingdom on 2024-01-06, 10:20:58 (24.27.41.140)
Cosmetically, it reminds me of the last generation AR turntable. However, the plastic platter and MDF chassis are not appealing. There might be something better in the Rega line at this price. ::: TO .......
93: Tube DIY Asylum, RE: Eastern Electric M88 schematic? (0.00)
Posted by Triode_Kingdom on 2024-01-05, 16:59:07 (24.27.41.140)
"you are a the mercy of replacing random capacitors and resistors." Why would that be the case? Depending on the severity of the distortion, a scope can probably see it. If a schematic can't be had, t .......
94: SET Asylum, RE: Nice OPT (0.00)
Posted by Triode_Kingdom on 2024-01-05, 07:06:47 (24.27.41.140)
I'll never build another high power (>5W) SET. I believe the performance limitations of available transformers render the goals of wide bandwidth, low bass performance and low distortion unattainable. .......
95: Tubes Asylum, Tube Friendly Speakers (0.00)
Posted by Triode_Kingdom on 2024-01-05, 06:52:39 (24.27.41.140)
I feel your pain. From what I've seen, very few, if any, contemporary speakers are "tube friendly." Even the high efficiency legacy types like Klipsch Cornwall sacrifice considerable low bass performa .......
96: Tubes Asylum, RE: New KT150, maybe? (0.00)
Posted by Triode_Kingdom on 2024-01-03, 16:55:55 (24.27.41.140)
For the cost of one set of tubes, you would be most of the way to a pair of high efficiency speakers. Once you've done that, a quad of 6L6 would blow you out of the room. :) .......
97: Vinyl Asylum, Spinning TOTO (1978) (0.00)
Posted by Triode_Kingdom on 2023-12-31, 20:37:56 (24.27.41.140)
This is really a nice pressing, but haven't played it in at least 30 years. Sounds wonderfully dynamic through the Citation V I restored recently. Never realized how much certain tracks sound like Gin .......
98: Vintage Asylum, RE: Ampex A423 The Longest Restoration (0.00)
Posted by Triode_Kingdom on 2023-12-31, 20:18:39 (24.27.41.140)
That's really a high-end product, must have been very expensive in its day. Beautiful 6V6 amplifiers! .......
99: Vinyl Asylum, RE: Rega P3 Noise (0.00)
Posted by Triode_Kingdom on 2023-12-31, 08:49:29 (24.27.41.140)
Does it make the noise when the tonearm is cued above the platter? Is it present with the motor turned off? .......
100: Vintage Asylum, RE: Recommendation for cleaning stubborn dust off old board (0.00)
Posted by Triode_Kingdom on 2023-12-30, 08:24:46 (24.27.41.140)
"I am thinking small paint brush with iso alcohol?" Yes, then dry it right away with compressed air. .......
101: Tubes Asylum, RE: DB110G (Bogen) 1950s. (0.00)
Posted by Triode_Kingdom on 2023-12-27, 20:32:51 (24.27.41.140)
I'm a big fan of the 6V6, but being a cheapskate, I've been collecting sleeves of NOS 12V6 for a long time. Recently replaced the well-worn 7408s in my small dual-mono SEP with 12V Sylvania chrome dom .......
102: Vinyl Asylum, RE: My take on this... (0.00)
Posted by Triode_Kingdom on 2023-12-27, 19:10:51 (24.27.41.140)
"True but aren't those scratches are on the lands, not down in the grooves?" This was audible in the program material. I began to notice it a couple years before I bought the Transcriptor. I was using .......
103: Tubes Asylum, RE: DB110G (Bogen) 1950s. (0.00)
Posted by Triode_Kingdom on 2023-12-27, 09:21:39 (24.27.41.140)
I won't use self bias (cathode bias) in any push-pull amplifier. Unless you're willing to bias the tubes nearly at Class A, crossover distortion sets in at higher output levels well before the limits .......
104: Vinyl Asylum, RE: My take on this... (0.00)
Posted by Triode_Kingdom on 2023-12-26, 20:48:25 (24.27.41.140)
"counter to the vast majority of those who clean their vinyl properly. " Not true, and I've been playing and discussing vinyl with other fanatics since the mid-'60s. Dust settles on the surface while .......
105: Vinyl Asylum, My take on this... (0.00)
Posted by Triode_Kingdom on 2023-12-26, 08:05:01 (24.27.41.140)
Every play of my albums through the years without a Dust Bug tracking the stylus has resulted in damage (pops/clicks). No amount of cleaning or brushing beforehand resolves this problem. ::: TOPIC .......
106: Tube DIY Asylum, RE: Modification of a Heath W5-M - Help and advice (0.00)
Posted by Triode_Kingdom on 2023-12-25, 09:40:17 (24.27.41.140)
1. Is the insulation of these old Peerless tranies strong enough to withstand this? 2. Is the insulation of the old filter choke strong enough to support this mode? 3. I assume, that the insulation o .......
107: Tube DIY Asylum, RE: What are you trying to accomplish? (0.00)
Posted by Triode_Kingdom on 2023-12-17, 09:30:48 (24.27.41.140)
"Question:the L1, L2 in the diagram, are they the bead type common mode inductors? Or they need to be the typical choke with air gap?" It depends on whether the noise is common mode or differential. I .......
108: Vinyl Asylum, RE: 70's turntable setup help request (0.00)
Posted by Triode_Kingdom on 2023-12-16, 14:32:05 (24.27.41.140)
The upper screw looks to me like a bearing adjustment. Don't think you want to turn that unless the tonearm has to be removed for some reason. .......
109: Tube DIY Asylum, RE: "bass and has full body" (0.00)
Posted by Triode_Kingdom on 2023-12-16, 12:04:21 (24.27.41.140)
"For instance driving a 300B, what 9 pin twin triode would sound more full body with tremendous stong bass is the target to achieve, 6H30 and 12BH7 may sound quite differently. Just want to find out t .......
110: Tube DIY Asylum, What are you trying to accomplish? (0.00)
Posted by Triode_Kingdom on 2023-12-16, 11:58:42 (24.27.41.140)
Engineering is about solving problems. Also, if you intend to use this ahead of a Rod Coleman regulator, it might be better to ask them about the application. .......
111: SET Asylum, Not necessarily (0.00)
Posted by Triode_Kingdom on 2023-12-09, 15:52:36 (24.27.41.140)
It depends on the operating point. I haven't used the 300B in any of my amps, but I played with the load line recently during an unrelated discussion elsewhere. The typical operating point of 350V wit .......
112: Tubes Asylum, But some tubes on eBay have been "refurbished" :) nt (0.00)
Posted by Triode_Kingdom on 2023-12-09, 15:48:47 (24.27.41.140)
nada aqui .......
113: Tube DIY Asylum, RE: Common mode (0.00)
Posted by Triode_Kingdom on 2023-12-09, 15:46:16 (24.27.41.140)
The AC current powering the filament is differential. A bifilar-wound common mode choke should have little effect on that. .......
114: Tube DIY Asylum, Common mode (0.00)
Posted by Triode_Kingdom on 2023-12-09, 04:14:41 (24.27.41.140)
For a DHT filament you would want to reject common mode noise. Common mode noise current is effectively in series with the filament and modulates it as a single element, relative to the grid. ::: TOP .......
115: Tubes Asylum, RE: 6n2p (0.00)
Posted by Triode_Kingdom on 2023-12-03, 07:34:50 (24.27.41.140)
I use them interchangeably (with consideration for the different filament connection). The 6N2P is an excellent tube. Note that the internal shield connected to pin 9 must be grounded to avoid odd eff .......
116: Amp/Preamp Asylum, RE: "Changes were allegedly made" (0.00)
Posted by Triode_Kingdom on 2023-12-03, 00:43:07 (24.27.41.140)
"One can argue whether or not carver liked or hated tubes" There's nothing to argue. Carver voiced his disdain for tubes on more than one occasion. It wasn't until some years after he could no longer .......
117: Tube DIY Asylum, RE: Divide it Axially (0.00)
Posted by Triode_Kingdom on 2023-12-03, 00:28:41 (24.27.41.140)
Each seciton of the pi wound choke is also wound in a criss-cross pattern. There was a hand-cranked machine on the market in the '60s and '70s that could be used at home to wind chokes like this. Don' .......
118: Amp/Preamp Asylum, RE: Here (0.00)
Posted by Triode_Kingdom on 2023-12-02, 13:53:04 (24.27.41.140)
Thanks, but have you seen the letter itself? It doesn't seem to be on the Facebook page for Skunkie, and "stereo.net" redirects to a URL that's for sale (no content). .......
119: Amp/Preamp Asylum, Where did you see that? (0.00)
Posted by Triode_Kingdom on 2023-12-02, 01:20:56 (24.27.41.140)
I don't have time to watch an entire video. Where did you see that the manufacturer is threatening to sue? .......
120: Amp/Preamp Asylum, "Changes were allegedly made" (0.00)
Posted by Triode_Kingdom on 2023-12-02, 01:18:51 (24.27.41.140)
I don't remember any followup on the part of those in the audio community who were testing the Carver amp. And the fact is, even if someone tested an improved example, you can never again trust the co .......
121: Tubes Asylum, RE: Unique George Wright phono stage question...... (0.00)
Posted by Triode_Kingdom on 2023-11-29, 15:53:16 (24.27.41.140)
Nice looking unit! Is the third 12AX7 working as a cathode follower for both channels? if so, it doesn't need to be matched to anything else. About the 6CA4, i wouldn't expect so much difference in so .......
122: Tube DIY Asylum, RE: A new PP-amp up and running (0.00)
Posted by Triode_Kingdom on 2023-11-29, 15:47:42 (24.27.41.140)
Nice finish on the wood frame. Love the glow tubes! .......
123: Tube DIY Asylum, RE: Transformer orientation (0.00)
Posted by Triode_Kingdom on 2023-11-27, 22:35:08 (24.27.41.140)
You should consider applying 60Hz to one transformer and rotating/positioning the other while viewing its winding(s) with a scope. The results might surprise you. .......
124: Tube DIY Asylum, RE: It won't. (0.00)
Posted by Triode_Kingdom on 2023-11-27, 22:31:36 (24.27.41.140)
"Whomever thought it was 3rd harmonic suppression really didn't understand the implication of the topology." The general audio knowledge base here and elsewhere is totally dysfunctional, thanks to the .......
125: Tube DIY Asylum, RE: The question doesn't match the content of your post (0.00)
Posted by Triode_Kingdom on 2023-11-25, 13:28:22 (24.27.41.140)
"This triode shown in schematic used to be 360 ohm cathode R now has been elevated to 90V above ground, say 8K instead od 360 ohm. In this case do we also take in account of 8K for calculation." Yes, .......
126: Tube DIY Asylum, RE: The question doesn't match the content of your post (0.00)
Posted by Triode_Kingdom on 2023-11-24, 14:07:25 (24.27.41.140)
"I was saying if the tube were elevated 90V above ground then what is the value of R3 we should take" So you're referring to elevating the first stage. Are you still asking about the bypass cap, or ar .......
127: Tube DIY Asylum, The question doesn't match the content of your post (0.00)
Posted by Triode_Kingdom on 2023-11-23, 23:26:53 (24.27.41.140)
Which bypass cap are you referring to? C3 is the only cathode bypass cap in the schematic. Not only is the cathode of that tube not elevated, the value of the cap seems to have already been calculated .......
128: Tubes Asylum, RE: C3G Siemens (0.00)
Posted by Triode_Kingdom on 2023-11-22, 06:31:45 (24.27.41.140)
If you don't find a suitable replacement at a decent price, maybe consider replacing that socket and using a different pentode. 9-pin miniatures are likely to be much less microphonic, and some are ve .......
129: Tubes Asylum, Which points out the fact that... (0.00)
Posted by Triode_Kingdom on 2023-11-21, 20:46:57 (24.27.41.140)
it's extraordinarily more difficult to achieve transparency with transistors than with tubes. The end result is that most commercial SS gear fails to achieve what was accomplished with tubes decades e .......
130: Tubes Asylum, Phase Inverter (0.00)
Posted by Triode_Kingdom on 2023-11-16, 16:02:33 (24.27.41.140)
"I'm thinking of converting my phase inverter tubes from 12AU7 to your 12AT7, since I already have some NOS JAN 12AT7s in stock." I will be very surprised if this produces any audible or measurable im .......
131: Tube DIY Asylum, Never a Problem in Audio Gear (0.00)
Posted by Triode_Kingdom on 2023-11-10, 07:04:58 (24.27.41.140)
The 6146 was intended for use in environments that were particularly unfriendly to high voltage. That includes high humidity and even the salt-laden air found on board ships at sea. The bakelite octal .......
132: Tubes Asylum, Screens (0.00)
Posted by Triode_Kingdom on 2023-11-04, 21:39:19 (24.27.41.140)
I think this is a terrible idea considering the market value of an unmolested Citation II. That aside, why would the screens need to be regulated? Wouldn't a LC network from B+ be sufficient? That's h .......
133: Tube DIY Asylum, RE: 6146 Based Tubes (0.00)
Posted by Triode_Kingdom on 2023-11-04, 14:23:03 (24.27.41.140)
I think the entire topology and many details would need to be revised to optimize a Citation II for pentode mode. That's one reason I own a Cit V. The signal path is configured exactly the way I like .......
134: Tube DIY Asylum, RE: 6146 Based Tubes (0.00)
Posted by Triode_Kingdom on 2023-11-04, 11:52:26 (24.27.41.140)
I've used them, but only in ham radio transmitters. You're absolutely correct about the attractive price point of some variants. The primary reasons I don't use them in audio are A) screen voltage lim .......
135: Vinyl Asylum, Dust Bug (0.00)
Posted by Triode_Kingdom on 2023-11-03, 21:44:37 (24.27.41.140)
I've been using a Dust Bug since the early '70s. Nothing else is required. The only time any of my LPs were ever damaged by dust and dirt was when I switched to Discwasher for a few months. ::: TOPIC: .......
136: Tubes Asylum, RE: Yes, the E1148 is a direct replacement for the 1193/CV6 tube. . . (0.00)
Posted by Triode_Kingdom on 2023-10-23, 05:56:24 (24.27.41.140)
"it was manufactured as a 1193 but named E1148 by Hytron" How do you know this? I don't have the Hytron data sheet, but I found one from the "Ministry of Supply (S.R.D.E.)" for the CV6. You originally .......
137: Tubes Asylum, RE: How does a lower current for the heater at the same voltage affect GM? (0.00)
Posted by Triode_Kingdom on 2023-10-22, 21:42:00 (24.27.41.140)
I read through your post several times, but it's still not clear to me exactly what you're asking. It doesn't seem to be the question in the subject line. Are you asking if the lower-than-expected Gm .......
138: Tubes Asylum, LOL (nt) (0.00)
Posted by Triode_Kingdom on 2023-10-17, 21:05:02 (24.27.41.140)
nada aqui .......
139: Tube DIY Asylum, RE: Canadian made Aim 62/36/2 is great (Mouser) (nt) (0.00)
Posted by Triode_Kingdom on 2023-10-16, 23:50:37 (24.27.41.140)
IMO, .025" is perfect for SS PCBs with ICs and transistors, but inconvenient when working on tube gear. Lately, I've been using .031" (0.8mm) and found it to be a good compromise. The formula is 63/37 .......
140: Tube DIY Asylum, RE: soldering station temperature (0.00)
Posted by Triode_Kingdom on 2023-10-15, 20:27:27 (24.27.41.140)
I use an older Weller WTCP 60W temp controlled iron (non-adjustable). Supposedly, temperature can be changed with different tips, but I don't know what's in it. Regardless, this iron does an extremely .......
141: Vintage Asylum, RE: Audio Innovations - problem with switches (0.00)
Posted by Triode_Kingdom on 2023-10-07, 23:31:02 (24.27.41.140)
You're dealing with such tiny signal levels, I wouldn't trust the switches once this happens. Digikey and Mouser probably have suitable replacements. Gold plated contacts would be the way to go, but I .......
142: Tube DIY Asylum, RE: fixed bias ???????????? (0.00)
Posted by Triode_Kingdom on 2023-10-06, 21:58:20 (24.27.41.140)
In addition to what Tre' said, I'll add that there's no reason to use anything other than the 1N4007 for this. .......
143: Tube DIY Asylum, RE: grounding (0.00)
Posted by Triode_Kingdom on 2023-10-05, 23:40:31 (24.27.41.140)
In addition to the issue of hum mentioned below, ground loops can also cause instability. When the chassis is used as a common ground, the ground current drawn by some stages will be mixed with the cu .......
144: Tube DIY Asylum, Have you seen this loadline calculator? (0.00)
Posted by Triode_Kingdom on 2023-10-05, 23:32:52 (24.27.41.140)
This calculator includes the 5687, ECC99 and 6DJ8 (but not the 6463). It allows you to vary the supply voltage, load resistance, grid bias and next stage loading. If you enter the anode voltage swing, .......
145: Tube DIY Asylum, There's no "best value" (0.00)
Posted by Triode_Kingdom on 2023-10-03, 13:27:54 (24.27.41.140)
I use 1Ω resistors for new builds, but HK used 3.3Ω in the Citation V, and many amplifiers use 10Ω. The 1Ω resistors you have are probably OK. Measuring low ohms requires a 4-wire ohmmeter, although s .......
146: Tubes Asylum, RE: No need for so many posts (0.00)
Posted by Triode_Kingdom on 2023-10-03, 00:02:19 (24.27.41.140)
"Only if it allows you to"? WTH does that mean? I just told you how to do it. .......
147: Tube DIY Asylum, No one here wants to hear about LoMu (0.00)
Posted by Triode_Kingdom on 2023-10-03, 00:00:18 (24.27.41.140)
There's a reason he's been banned from every audio forum on the planet. Maybe you could do this privately, huh? .......
148: Tubes Asylum, No need for so many posts (0.00)
Posted by Triode_Kingdom on 2023-10-02, 18:18:06 (24.27.41.140)
You can post multiple images in one post by clicking on "Preview Message." Each time you do that, another image can be uploaded into the post. Sorry, I can't help with a definitive ID on the tube. :: .......
149: Tube DIY Asylum, RE: Parasitic Suppressors (0.00)
Posted by Triode_Kingdom on 2023-09-30, 10:58:02 (24.27.41.140)
Well, I wouldn't use anything at the anode (pin 3). You certainly wouldn't want to add unnecessary resistance there, and I don't believe oscillation is an issue if the other stoppers are in place. The .......
150: Tube DIY Asylum, RE: Parasitic Suppressors (0.00)
Posted by Triode_Kingdom on 2023-09-30, 07:23:43 (24.27.41.140)
Just to flesh this out, the resistor is usually 1W or 2W, and it must be carbon comp like the photo. Resistors constructed with an internal spiral track, such as carbon film and metal film, are ineffe .......
151: Tube DIY Asylum, Parasitic Suppressors (0.00)
Posted by Triode_Kingdom on 2023-09-29, 13:56:55 (24.27.41.140)
Your friend is suggesting a technique that is commonly applied to the anodes (and less commonly the screens) of transmitting tubes. You can use almost any type of wire for this - enameled or tinned - .......
152: Tube DIY Asylum, RE: Didja Get The E-Mail Announcement From Digikey? (0.00)
Posted by Triode_Kingdom on 2023-09-28, 19:32:31 (24.27.41.140)
Good for them. Let's hope the level of service they provide us "little people" continues. .......
153: Tubes Asylum, RE: Conrad-Johnson PV-10B: Low-level Hum (0.00)
Posted by Triode_Kingdom on 2023-09-25, 18:08:40 (24.27.41.140)
A shorted regulator or pass transistor in the power supply can also cause hum. I think you should try to determine whether it's 60Hz or 120Hz before continuing. .......
154: Tube DIY Asylum, RE: AMPERITE 6NO15 TIME DELAY RELAY (0.00)
Posted by Triode_Kingdom on 2023-09-24, 15:47:49 (24.27.41.140)
Does this power supply feed everything in the amplifier? If so, B+ won't exist until some time after the relay closes (it requires time for the filter caps to charge). That should prevent a large tran .......
155: Tube DIY Asylum, I think that's only part of the story (0.00)
Posted by Triode_Kingdom on 2023-09-21, 13:24:31 (24.27.41.140)
Before I retired, I would often order a small quantity of an item to test and develop a design. Then our purchasing department would order the hundreds or thousands needed for production. OTOH, I thin .......
156: Tube DIY Asylum, RE: Dennis Fraker ST70 Board? (0.00)
Posted by Triode_Kingdom on 2023-09-16, 15:24:46 (24.27.41.140)
I believe Dennis posts here using the name "tube wrangler". You might try messaging him through the Asylum system. .......
157: Tube DIY Asylum, RE: The Coleman regulators are nice but don't like hash (0.00)
Posted by Triode_Kingdom on 2023-09-14, 13:24:26 (24.27.41.140)
I've been buying Signal transformers and chokes for projects, the same brand Tre' mentioned. I think they're the only company making these that hasn't moved operations to China. .......
158: Tube DIY Asylum, RE: Help!! Hum on restored vintage tube amp (0.00)
Posted by Triode_Kingdom on 2023-09-13, 18:19:54 (24.27.41.140)
In that case, it would be worthwhile to reverse the AC connections in the amp for a test. The unmodified amps might be wired a certain way to accommodate transformer leakage. The fact that the hum dis .......
159: Tube DIY Asylum, RE: Help!! Hum on restored vintage tube amp (0.00)
Posted by Triode_Kingdom on 2023-09-13, 14:32:15 (24.27.41.140)
Does the hum level change when you reverse the AC plug? How sensitive are your speakers? .......
160: Tube DIY Asylum, RE: The Coleman regulators are nice but don't like hash (0.00)
Posted by Triode_Kingdom on 2023-09-13, 14:24:46 (24.27.41.140)
So the output of the supply is clean, and this is strictly an issue of EMI? Do you think the problem might be the power transformer itself? I would try mounting the iron in a steel enclosure before gi .......
161: Tube DIY Asylum, DHT Filaments (0.00)
Posted by Triode_Kingdom on 2023-09-13, 07:12:53 (24.27.41.140)
Somehow I missed the fact that you are powering DHTs. Sorry, my fault. I agree with the other posts that a conventional SMPS isn't a good choice. Are you using Schottky rectifiers for this, but still .......
162: Tube DIY Asylum, RE: Rectifier tubes (0.00)
Posted by Triode_Kingdom on 2023-09-11, 19:59:20 (24.27.41.140)
I wouldn't spend the money unless the Russian tubes are routinely failing. .......
163: Tube DIY Asylum, RE: Any tricks for shielding diodes on filament supplies? (0.00)
Posted by Triode_Kingdom on 2023-09-11, 19:56:58 (24.27.41.140)
My only suggestion would be to use a SMPS. They're small and inexpensive. .......
164: Tubes Asylum, Correct - "retains its 800KHz operating frequency" (NT) (0.00)
Posted by Triode_Kingdom on 2023-09-05, 18:09:01 (24.27.41.140)
nada aqui .......
165: Tube DIY Asylum, Save your breath - Wilbur crossposted (0.00)
Posted by Triode_Kingdom on 2023-09-01, 12:31:09 (24.27.41.140)
to a different Website and is pursuing the conversation over there. I really hate it when people do this, especially when they don't even bother to let other members know. .......
166: Vintage Asylum, A truly convoluted review! (0.00)
Posted by Triode_Kingdom on 2023-08-31, 12:53:02 (24.27.41.140)
The author sings their praises for 95% of the review, then closes with two examples of unexciting designs that easily best them. I remember the DQ-10 from when it was new, and I can tell you I wouldn' .......
167: Tube DIY Asylum, RE: Resistor used for measuring bias keeps failing -- what can I do? (0.00)
Posted by Triode_Kingdom on 2023-08-28, 13:53:19 (24.27.41.140)
I wouldn't expect this to need a resistor larger than 1W. What type of resistor have you been replacing it with? A 1% metal oxide or wirewound should last several lifetimes. Digikey has both types at .......
168: Tube DIY Asylum, Feedback Measurement (0.00)
Posted by Triode_Kingdom on 2023-08-27, 11:06:35 (24.27.41.140)
I measured NF at three different frequencies because I don't know how accurate my multimeter is at the midrange frequencies I'm getting the following NF: 60hz 6db 500hz 9.5db 1000hz 11.5db I've neve .......
169: Tube DIY Asylum, RE: e80cc operating points in SRPP (0.00)
Posted by Triode_Kingdom on 2023-08-27, 08:38:14 (24.27.41.140)
"But what about all these designers that swear that NF is bad, and they just leave it out completely- even on a SE kt88?" It's inconceivable to me that any educated designer would do that. The distort .......
170: Tubes Asylum, That's good to hear! (0.00)
Posted by Triode_Kingdom on 2023-08-26, 21:33:26 (24.27.41.140)
I have enough power tubes to last for years, but I used the last of my 12AX7s in a DIY guitar amp awhile back. I'll need to replenish those before too long. JJ it is! .......
171: Tube DIY Asylum, RE: e80cc operating points in SRPP (0.00)
Posted by Triode_Kingdom on 2023-08-26, 14:47:17 (24.27.41.140)
"Not sure how much Nf I need, or how to calculate, but based on volume it seems to be 6 db or so..." Drive the amplifier with a 1kHz sine wave so it produces a couple volts at the output. Now measure .......
172: Tube DIY Asylum, He has abandoned ship (0.00)
Posted by Triode_Kingdom on 2023-08-26, 12:05:15 (24.27.41.140)
You should have apologized. "You're a very bad man." - Babu Bhatt :) .......
173: Tube DIY Asylum, RE: e80cc operating points in SRPP (0.00)
Posted by Triode_Kingdom on 2023-08-26, 12:02:06 (24.27.41.140)
A single-ended pentode output with no NFB will produce a huge amount of IM distortion. Every effort to create a high quality amplifier will be defeated by this. I would suggest that you abandon the SR .......
174: Tubes Asylum, RE: If they do export, I won't buy them. (0.00)
Posted by Triode_Kingdom on 2023-08-26, 11:10:55 (24.27.41.140)
Same here. I also try not to buy Chinese parts. These governments are responsible for horrendous atrocities, and it's ongoing. .......
175: Tube DIY Asylum, RE: e80cc operating points in SRPP (0.00)
Posted by Triode_Kingdom on 2023-08-26, 11:02:53 (24.27.41.140)
I don't think that design has enough gain. How much feedback are you using (dB)? .......
176: Tube DIY Asylum, RE: Galvanic corrosion: Is it a concern in our projects? (0.00)
Posted by Triode_Kingdom on 2023-08-25, 19:58:33 (24.27.41.140)
This topic comes up frequently on forums visited by those of us who own aluminum boats. The degree of corrosive activity depends not only on the specific metals involved, but also which of the metals .......
177: Tube DIY Asylum, RE: Please don't start this nonsense again (0.00)
Posted by Triode_Kingdom on 2023-08-24, 19:18:31 (24.27.41.140)
"All tubes have cathode resistors that provide bias.' This is what you said. It isn't true. Now you're making it personal to avoid having to admit the error. Something is wrong with you. .......
178: Tube DIY Asylum, Please don't start this nonsense again (0.00)
Posted by Triode_Kingdom on 2023-08-24, 16:10:23 (24.27.41.140)
Your statement about cathode resistors is incorrect. Just admit it and move on. .......
179: Tube DIY Asylum, RE: Just another bogus Internet schematic (0.00)
Posted by Triode_Kingdom on 2023-08-24, 10:01:04 (24.27.41.140)
"All tubes have cathode resistors that provide bias." The 5755 can operate at zero bias with no cathode resistor at typical anode voltages. The curves are not like the other types listed in the OP's s .......
180: Tube DIY Asylum, Just another bogus Internet schematic (0.00)
Posted by Triode_Kingdom on 2023-08-23, 08:13:44 (24.27.41.140)
The tube types listed at each location need differing operating points. The 5755 in particular is very different from the others. Surely there's a legitimate commercial LCR schematic somewhere online? .......
181: Tube DIY Asylum, RE: Are tantalum resistors appropriate for grid stopper? (0.00)
Posted by Triode_Kingdom on 2023-08-22, 07:20:44 (24.27.41.140)
Any resistor with a spiral resistive track will be less effective for this purpose than carbon comp. How are the tantalums made? .......
182: Tube DIY Asylum, And they have disadvantages (0.00)
Posted by Triode_Kingdom on 2023-08-20, 14:33:43 (24.27.41.140)
Namely, cost and size. Aluminum electrolytics work really well for most things, and they typically last two to four decades. That puts replacement into the next reincarnation for me. :) .......
183: Tubes Asylum, RE: Do 6CG7s interchange with anything? (0.00)
Posted by Triode_Kingdom on 2023-08-16, 07:43:58 (24.27.41.140)
The benefit of changing a 12AU7 to a more linear tube depends on how the 'AU7 is being used. If it's a cathode follower, the effort is wasted. Same is likely true if it's a long tail pair (due to the .......
184: Tubes Asylum, RE: Can't ask the circuit designer.. (0.00)
Posted by Triode_Kingdom on 2023-08-14, 19:19:06 (24.27.41.140)
Hmmm, I was part of that discussion you linked. Sorry to hear about the designer. You can't post the two schematics? .......
185: Tubes Asylum, Measurements or it didn't happen... (0.00)
Posted by Triode_Kingdom on 2023-08-14, 14:21:02 (24.27.41.140)
I've heard this sort of thing way too many times, only to see it shot down later. Differences like this are almost always the result of the builder hearing what he wants to. Would be interested in see .......
186: Tubes Asylum, RE: 12SN7 vs. 6BL7 (0.00)
Posted by Triode_Kingdom on 2023-08-13, 21:16:13 (24.27.41.140)
The 6BL7 isn't as linear as the 'SN7, but it probably doesn't matter much in an amp with significant NFB. "The performance of the amp improved across the board. The bass improved, the midrange sounded .......
187: Tubes Asylum, RE: Are these real fat base Mullards? (0.00)
Posted by Triode_Kingdom on 2023-08-13, 21:11:41 (24.27.41.140)
Use some common sense man. They're shipping from China. .......
188: Tube DIY Asylum, RE: Yes ... (0.00)
Posted by Triode_Kingdom on 2023-08-11, 17:02:47 (24.27.41.140)
"... assuming the load impedance is much greater than 600 ohms." Is that a realistic expectation? Do we know that the response of this transformer doesn't degrade when it's very lightly loaded? ::: .......
189: Tubes Asylum, 15X is too much gain (nt) (0.00)
Posted by Triode_Kingdom on 2023-08-11, 12:05:52 (24.27.41.140)
nada aqui .......
190: Tubes Asylum, RE: Which tube among suitable for linestage? (0.00)
Posted by Triode_Kingdom on 2023-08-11, 06:11:25 (24.27.41.140)
I don't think any of those are particularly well suited to this use. If it's purely a linestage, my choice would probably be a 6SN7 or 12B4, maybe also a 7044 or 5687. .......
191: Tube DIY Asylum, RE: Help: Pentode current sink for output triode (0.00)
Posted by Triode_Kingdom on 2023-08-07, 12:38:51 (24.27.41.140)
That's a very high transconductance tube with response into the low VHF region. I'm guessing your layout is encouraging RF feedback when the additional circuitry is connected. Simply having more condu .......
192: Tube DIY Asylum, RE: "Chopstick method"? (0.00)
Posted by Triode_Kingdom on 2023-08-07, 12:33:24 (24.27.41.140)
People who build high-gain guitar amplifiers are probably more familiar with this terminology. Essentially, it describes the method of poking and prodding wiring and components in the circuit with an .......
193: Tube DIY Asylum, RE: Help: Pentode current sink for output triode (0.00)
Posted by Triode_Kingdom on 2023-08-07, 04:49:56 (24.27.41.140)
Have you tried the "chopstick" method? That might tell you which areas of the circuit are sensitive. It would also be helpful to post a schematic and photo of the layout. No one can help much without .......
194: Tube DIY Asylum, RE: You have to use a series resistance (0.00)
Posted by Triode_Kingdom on 2023-08-03, 11:34:49 (24.27.41.140)
Thanks for mentioning this. I think Fisher did that in a few models, probably other brands as well. In my preamp (under construction), a "Stereo-Rev-Mono" switch precedes the balance control. Each cha .......
195: Tube DIY Asylum, RE: Why not use a shunt style balance control? (0.00)
Posted by Triode_Kingdom on 2023-08-02, 21:30:04 (24.27.41.140)
Is that the configuration where the wiper is grounded? That's a good approach, but this is a preamp with a minimalist (passive) signal path up to the balance control. I'm concerned that the wiper woul .......
196: Tube DIY Asylum, Have you used the Fender (Alpha) version? (0.00)
Posted by Triode_Kingdom on 2023-08-01, 19:29:14 (24.27.41.140)
AES sells a 250K MN taper made for Fender. I ran a simulation of both values, and there's very little difference in terms of loss or loading in my circuit. The Alpha looks like it might be a better qu .......
197: Tube DIY Asylum, MN Taper Pots (0.00)
Posted by Triode_Kingdom on 2023-07-31, 19:12:14 (24.27.41.140)
I'm building a preamp from scratch and have just stumbled across the MN taper pots at Antique Electronic Supply. These look perfect for a Balance control, better than the plain ALPS linear pots I had .......
198: Tubes Asylum, NOT a Vacuum Tube (0.00)
Posted by Triode_Kingdom on 2023-07-29, 08:24:05 (24.27.41.140)
"Input voltage noise density: 1.2nV/√Hz" No vacuum tube comes close to that. This might be a FET-input design, but I'm betting it's just a low noise opamp. .......
199: Tubes Asylum, RE: EC8020 (0.00)
Posted by Triode_Kingdom on 2023-07-28, 14:21:34 (24.27.41.140)
I don't know which math you're referring to, but that's a really crappy way to mount vacuum tubes. .......
200: Tube DIY Asylum, And Hammond Organs (nt) (0.00)
Posted by Triode_Kingdom on 2023-07-26, 12:03:33 (24.27.41.140)
nada aqui .......
201: Vintage Asylum, RE: He was an incredible resource about Fisher gear (0.00)
Posted by Triode_Kingdom on 2023-07-24, 06:50:27 (24.27.41.140)
I don't have direct experience with 7591 reissues. However, Jim continued to sell all the Russian brands up until the Ukraine invasion. That tells me they were/are much better than JJ and not prone to .......
202: Tube DIY Asylum, RE: Here's the chart you ask for (0.00)
Posted by Triode_Kingdom on 2023-07-23, 18:07:50 (24.27.41.140)
I've seldom seen posts from anyone so dedicated to remaining uninformed. .......
203: Vintage Asylum, RE: He was an incredible resource about Fisher gear (0.00)
Posted by Triode_Kingdom on 2023-07-23, 16:03:09 (24.27.41.140)
The JJ 7591s had a reputation for that. Jim McShane wouldn't sell them after it was realized they were so prone to failure. Their preamp tubes seem to be holding up pretty well, though. .......
204: Vintage Asylum, RE: Fisher 500C Up and running again (0.00)
Posted by Triode_Kingdom on 2023-07-22, 08:40:30 (24.27.41.140)
Are they fusible resistors? I'm not a fan of relying on standard resistors to burn up and go open. Instrument amp manufacturers used to install a B+ fuse for this purpose. Oh well, I guess any protect .......
205: Tube DIY Asylum, RE: Allen Wright was correct (0.00)
Posted by Triode_Kingdom on 2023-07-22, 08:26:47 (24.27.41.140)
"the current surge turns your power transformer into a RFI generation machine!!!" I have never been able to detect any such effect through testing of either the power supply or the audio signal path. .......
206: Vintage Asylum, RE: Fisher 500C Up and running again (0.00)
Posted by Triode_Kingdom on 2023-07-21, 18:20:04 (24.27.41.140)
Glad it's OK. Those aren't safety resistors. They're installed to allow measuring the idle bias at each tube. .......
207: Tube DIY Asylum, RE: All Electronics in LA is closing! (0.00)
Posted by Triode_Kingdom on 2023-07-20, 14:54:41 (24.27.41.140)
Our only surplus component store closed more than 10 years ago and liquidated everything on eBay. I used to patronize the local Fry's whenever possible, but they're also long gone now. We still have A .......
208: Tube DIY Asylum, RE: ultrasonic filament supply (0.00)
Posted by Triode_Kingdom on 2023-07-19, 22:00:32 (24.27.41.140)
I installed the modules in the Pomona boxes primariy for safety reasons. I milled slots in the boxes for ventilation, and the boards are insulated from the boxes using .020" FR4 that I also milled to .......
209: Tube DIY Asylum, RE: Here's the chart you ask for (0.00)
Posted by Triode_Kingdom on 2023-07-19, 21:21:29 (24.27.41.140)
"Does Tre's info tell you maximum size of capacitor to use " YES. Tre pointed out that A) the information in the datasheets prescribes maximum allowable current, and B) the maximum value capacitor wit .......
210: Tube DIY Asylum, RE: Here's the chart you ask for (0.00)
Posted by Triode_Kingdom on 2023-07-19, 18:39:13 (24.27.41.140)
"Tre's info is useless to the audiophile here." I'm an audiophile. It's not useless to me. .......
211: Tube DIY Asylum, RE: SET PS (0.00)
Posted by Triode_Kingdom on 2023-07-19, 16:32:22 (24.27.41.140)
"Back when I was doing research on DHT filament supplies, the AC supplies seemed to provide a more lively sound, but that damn hum." I experienced the same thing, and others have too. No one seems to .......
212: Tube DIY Asylum, RE: ultrasonic filament supply (0.00)
Posted by Triode_Kingdom on 2023-07-19, 16:16:44 (24.27.41.140)
The supplies aren't too complicated, but the writeup is somewhat lengthy. It's better if I just provide a link to where I posted the process. You might need to join in order to see the images (it's fr .......
213: Tube DIY Asylum, RE: One more (0.00)
Posted by Triode_Kingdom on 2023-07-19, 16:00:35 (24.27.41.140)
"Now, who would use a 275ma 5U4GB at 60ma? Please." Why do you come to a forum populated by more knowledgable members and then argue with them? You could at least try to understand the concept being p .......
214: Tube DIY Asylum, RE: Here's the chart you ask for (0.00)
Posted by Triode_Kingdom on 2023-07-18, 21:25:25 (24.27.41.140)
"Now who would use a 100K resistor in-between a rectifier and input capacitor-" But do you believe doing so would still mandate a maximum value of 40uF? That's the question. .......
215: Tube DIY Asylum, RE: Here's the chart you ask for (0.00)
Posted by Triode_Kingdom on 2023-07-18, 19:35:27 (24.27.41.140)
There's no reason to make this personal. Tre is correct - the maximum capacitance that can be used is purely a function of peak current. That, in turn, is determined by the transformer voltage and ser .......
216: Tube DIY Asylum, SET PS (0.00)
Posted by Triode_Kingdom on 2023-07-18, 19:06:35 (24.27.41.140)
Each of my monoblocks has one of these PS plates. That's three 680uF computer grade caps in series for the output tube (CLC). The plate contains a separate power transformer/filter for the preamp and .......
217: Tube DIY Asylum, System Bass (0.00)
Posted by Triode_Kingdom on 2023-07-14, 21:45:01 (24.27.41.140)
"Most 'quality' tube amps have inferior bass compared to really good solid-state." My experience has been just the opposite, and I've owned and listened to some pretty good SS gear over the years. The .......
218: Tube DIY Asylum, RE: Bringing down the ripple......? (0.00)
Posted by Triode_Kingdom on 2023-07-13, 13:07:58 (24.27.41.140)
The larger the value of the last cap becomes, the lower the output Z of the supply will be. The lower the output Z becomes, the less you will hear the supply and the more you will hear the amplifier. .......
219: Tubes Asylum, RE: Jolida JD-9 phono preamp (0.00)
Posted by Triode_Kingdom on 2023-07-12, 16:18:48 (24.27.41.140)
Carefully engineered... meticulously designed... This is Chinese consumer grade, so I think that's really a stretch. I agree though about the need to accommodate various tube types with appropriate ci .......
220: Vintage Asylum, RE: how to connect phono section of HH Scott 121-C (0.00)
Posted by Triode_Kingdom on 2023-07-11, 20:33:49 (24.27.41.140)
"From the Photo of the front- it looks like it has Most of the curves necessary-not quite sure what the areas in between selections might yield..." Maybe I misunderstood the OP's intent. I thought he .......
221: Tubes Asylum, RE: The gain stages in the Jolida are ICs (0.00)
Posted by Triode_Kingdom on 2023-07-11, 20:30:59 (24.27.41.140)
"The tubes are used solely as cathode followers, which add no gain, and are there so that it can be sold as a tube unit." More and more fraudulent junk like that has appeared on the market over the la .......
222: Vintage Asylum, RE: how to connect phono section of HH Scott 121-C (0.00)
Posted by Triode_Kingdom on 2023-07-11, 13:28:05 (24.27.41.140)
"No I will not be using ceramic cartridges." OK, so you'll be using a magnetic cartridge with a 78 RPM stylus. IN that case... "I was wondering how (if) I can connect Scott's phono stage to my current .......
223: Tube DIY Asylum, RE: Big difference! (0.00)
Posted by Triode_Kingdom on 2023-07-11, 13:17:07 (24.27.41.140)
"The usage is to set a current limit which unlike a fuse or conventional magnetic and/or thermal circuit breaker will disconnect the load within a 60hz cycle." How would that be useful? If an amplifie .......
224: Vintage Asylum, RE: how to connect phono section of HH Scott 121-C (0.00)
Posted by Triode_Kingdom on 2023-07-11, 07:04:57 (24.27.41.140)
If you will be using a ceramic cartridge, no phono preamp will be needed. .......
225: Tube DIY Asylum, RE: Big difference! (0.00)
Posted by Triode_Kingdom on 2023-07-11, 06:58:30 (24.27.41.140)
I was in this business for about 20 years in the '70s and '80s. We used a Variac and meter for all testing, and I never heard of a professional service center using anything else. Regarding the fast-a .......
226: Tubes Asylum, RE: Unexpected longevity (0.00)
Posted by Triode_Kingdom on 2023-07-09, 13:03:27 (24.27.41.140)
My experience with most Soviet tubes has been extremely positive. There are a few types I don't care for, but that has nothing to do with reliability. Wish I had bought more of the original Svetlana t .......
227: Tube DIY Asylum, RE: Commodity Edison light bulb sales illegal in USA on 8/1/2023? (0.00)
Posted by Triode_Kingdom on 2023-07-06, 13:45:37 (24.27.41.140)
My understanding is that specialty bulbs are exempt. That should include photofloods, although the ones I'm familiar with are only available in higher wattages. .......
228: Tube DIY Asylum, I ran a signal through a potato once (nt) (0.00)
Posted by Triode_Kingdom on 2023-07-05, 19:57:05 (24.27.41.140)
nada aqui .......
229: Vintage Asylum, RE: How to remove turntable (0.00)
Posted by Triode_Kingdom on 2023-07-05, 13:04:06 (24.27.41.140)
Don't those metal catches flip down? Then you turn them to line up with the slots and pull the TT out. .......
230: Vintage Asylum, RE: Repair and restoration guide (0.00)
Posted by Triode_Kingdom on 2023-07-03, 06:44:22 (24.27.41.140)
I've never seen anything like that. The best we can do it seems is to encourage newcomers asking for help to always list their location. I wish this was part of the new member instructions on every fo .......
231: Tubes Asylum, Very seldom (0.00)
Posted by Triode_Kingdom on 2023-06-26, 15:04:40 (24.27.41.140)
I've purchased a number of vintage '60s amplifiers that had the original tubes and didn't need them to be replaced. My small SEP amp needed the two outputs replaced recently, but they were pulls from .......
232: Tube DIY Asylum, RE: Thanks! (0.00)
Posted by Triode_Kingdom on 2023-06-25, 15:36:52 (24.27.41.140)
Most of the data sheet links point to http://frank.yueksel.org/. It's still down. .......
233: Tube DIY Asylum, Barely noticeable unless it's enough to prevent clipping (nt) (0.00)
Posted by Triode_Kingdom on 2023-06-20, 14:00:32 (24.27.41.140)
nada aqui .......
234: SET Asylum, RE: 845 vs 805 (0.00)
Posted by Triode_Kingdom on 2023-06-18, 16:27:09 (24.27.41.140)
"Which one is more linear " It depends on the operating conditions. The 845 is very linear over most of the typical Class A operating range. The 805 is also very linear if operated at lower anode volt .......
235: SET Asylum, RE: 845 vs 805 (0.00)
Posted by Triode_Kingdom on 2023-06-18, 00:44:46 (24.27.41.140)
The answer to that question is highly dependent on the driver. The 805 is a Class B triode, so the IT secondary must be capable of supplying DC grid bias. In addition, the driver must supply audio pow .......
236: Tube DIY Asylum, RE: Back in the 70s Disco days... (0.00)
Posted by Triode_Kingdom on 2023-06-16, 08:24:42 (24.27.41.140)
"One of the most popular power amps was the Dynaco MK6. It was ultra reliable. The SS amps of the day, Dynaco 400, Phase Linear 400, Marantz 500, would consistently fail under nightly stress at those .......
237: Tube DIY Asylum, Thanks! (0.00)
Posted by Triode_Kingdom on 2023-06-14, 09:27:24 (24.27.41.140)
The links at Duncanamps only point to the main site. The others do seem to be working. .......
238: Tube DIY Asylum, Tube Datasheets Gone? (0.00)
Posted by Triode_Kingdom on 2023-06-14, 07:06:12 (24.27.41.140)
Most of the TDSL Duncanamps tube database is linked to sheets located at http://frank.yueksel.org/. That URL has been down for several days. Have we lost this resource? .......
239: Tube DIY Asylum, RE: Carlson's Lab goes inside a 400 lb. Audio Research monoblock. (0.00)
Posted by Triode_Kingdom on 2023-06-13, 17:31:13 (24.27.41.140)
The problem with AR is the absurd level of unnecessary complexity. The D70 is a good example of this. Nine tube sections in each channel, and more (plus numerous ICs and transistors) in the power supp .......
240: Tube DIY Asylum, RE: Carlson's Lab goes inside a 400 lb. Audio Research monoblock. (0.00)
Posted by Triode_Kingdom on 2023-06-13, 07:39:48 (24.27.41.140)
I have yet to see even one piece of equipment from this company that I would want to own. .......
241: Tube DIY Asylum, Parafeed SE (0.00)
Posted by Triode_Kingdom on 2023-06-09, 12:11:06 (24.27.41.140)
What I find attractive about parafeed is the elimination of the shortcomings of large gapped transformers. I'm interested in the concept of a parafeed design that would combine a relatively inexpensiv .......
242: Tube DIY Asylum, RE: Parafeed caps, who needs them? (0.00)
Posted by Triode_Kingdom on 2023-06-09, 10:57:07 (24.27.41.140)
Being as this is the DIY forum... How about a large bank of Leyden jars? Actually, I've become more interested in parafeed lately. What type choke do you use with the 2A3s? .......
243: Tubes Asylum, RE: JoLida 811A Tube Info (0.00)
Posted by Triode_Kingdom on 2023-06-08, 07:43:45 (24.27.41.140)
"These are Ham radio RF tubes, not for audio." Have you told Altec? :) .......
244: Tube DIY Asylum, There's also Primary Windings (0.00)
Posted by Triode_Kingdom on 2023-06-04, 16:17:59 (24.27.41.140)
Made in Britain, seem to be more reasonably priced. Not familiar with their availability or quality personally. Looks like they have offerings for both guitar and hi-fi. .......
245: Tube DIY Asylum, You should try to understand the discussion before posting nt (0.00)
Posted by Triode_Kingdom on 2023-05-30, 12:48:47 (24.27.41.140)
nada aqui .......
246: Tubes Asylum, RE: Any Info/Opinions on Realistic 7591A Tubes? (0.00)
Posted by Triode_Kingdom on 2023-05-30, 09:34:33 (24.27.41.140)
That doesn't make sense. Tubes made in Japan don't look like tubes made in USA. Hope this works out OK for you. .......
247: Tube DIY Asylum, RE: Preliminary test... (0.00)
Posted by Triode_Kingdom on 2023-05-30, 09:32:36 (24.27.41.140)
The best solution would be a good quality 5K transformer with multiple taps for headphones. AFAIK, Magnequest was the only company making anything like this. I have a few 5K:8 transformers of decent q .......
248: Tubes Asylum, RE: Any Info/Opinions on Realistic 7591A Tubes? (0.00)
Posted by Triode_Kingdom on 2023-05-29, 21:00:07 (24.27.41.140)
Three marked USA and one marked Japan does not constitute a matched quad. .......
249: Vintage Asylum, He already posted elsewhere (0.00)
Posted by Triode_Kingdom on 2023-05-29, 14:53:36 (24.27.41.140)
Saw it on AudioKarma. Guess he was in a hurry. :) .......
250: Tubes Asylum, RE: Any Info/Opinions on Realistic 7591A Tubes? (0.00)
Posted by Triode_Kingdom on 2023-05-29, 14:51:34 (24.27.41.140)
I would be hesitant to buy them if they're not a matched quad. They would need to be very inexpensive. .......
251: Vintage Asylum, But Crossposting Not Allowed... (0.00)
Posted by Triode_Kingdom on 2023-05-28, 20:04:30 (24.27.41.140)
And he can't delete it now because there's been a reply. Only solution I know is for him to contact the mods and ask them to move it. .......
252: Tubes Asylum, RE: It was the tube. (0.00)
Posted by Triode_Kingdom on 2023-05-27, 18:32:47 (24.27.41.140)
You said: "only made the noise when I turn up or down the volume, other than that it was dead quiet." How could the VC make noise unless the tube was oscillating? Probably the measurement just missed .......
253: Tube DIY Asylum, RE: Preliminary test... (0.00)
Posted by Triode_Kingdom on 2023-05-27, 10:01:38 (24.27.41.140)
Those numbers are encouraging. Here's a hypothetical: Let's say the transformer has two 120V primaries and two 20V secondaries. The secondaries might have higher DCR than the 9V windings you measured, .......
254: Tubes Asylum, RE: Weird tube noise... (0.00)
Posted by Triode_Kingdom on 2023-05-26, 23:10:35 (24.27.41.140)
I would guess that it was oscillating. Does the preamp use grid stoppers? .......
255: Tube DIY Asylum, RE: Preliminary test... (0.00)
Posted by Triode_Kingdom on 2023-05-26, 22:04:16 (24.27.41.140)
That's a good point about DCR. Do you know the DCR of each 9V winding in the 0209? Maybe it's more appropriate just to use the secondaries as an autoformer and not work with the primary-secondary rati .......
256: Tube DIY Asylum, Preliminary test... (0.00)
Posted by Triode_Kingdom on 2023-05-26, 15:29:17 (24.27.41.140)
I decided to test a small toroid transformer that I found. It's rated 120V (single primary) with 16V output (no CT), and 45VA. Rather than drag my amplifier to the workbench, I used a 50Ω generator to .......
257: Tube DIY Asylum, RE: Who Was Using Toroidal PTs for Outputs? (0.00)
Posted by Triode_Kingdom on 2023-05-26, 13:30:07 (24.27.41.140)
Thanks for your input. This application will involve less than 1/4W of audio, and the first practical use will be a 1:2 turns ratio to match an 8Ω amplifier output to 32Ω headphones. For this, it was .......
258: Tube DIY Asylum, Who Was Using Toroidal PTs for Outputs? (0.00)
Posted by Triode_Kingdom on 2023-05-25, 19:56:57 (24.27.41.140)
I'm thinking about using a small toroidal power transformer to match 8Ω output to higher Z headphones. No DC, just a very small audio voltage. Wondering if anyone has measured the bandwidth in an .......
259: Vintage Asylum, RE: Rebuilding my Accuphase E-202 (0.00)
Posted by Triode_Kingdom on 2023-05-20, 21:06:59 (24.27.41.140)
A better question might be to ask what is your experience? I performed warranty service for most of the major audio brands back in the day, including Teac and Accuphase. Restoration now - more than 40 .......
260: SET Asylum, Photo Uploads (0.00)
Posted by Triode_Kingdom on 2023-05-19, 14:14:14 (24.27.41.140)
You can post multiple picture in one message by preforming a preview and adding another image. Do that as many times as needed to get them all into one post. .......
261: Tubes Asylum, RE: Very interesting! (0.00)
Posted by Triode_Kingdom on 2023-05-19, 08:15:41 (24.27.41.140)
Yes, the amp is very quiet with the ultrasonic supply. The project is essentially complete now, just need to finish a few cosmetic items. Yay! .......
262: Tube DIY Asylum, RMS Measurement (0.00)
Posted by Triode_Kingdom on 2023-05-17, 13:05:03 (24.27.41.140)
"Most non true RMS meters can measure frequencies wider than 60Hz, but you only get an accurate RMS value for sine waves only." I've seen quite a few DVMs that displayed a value closer to average than .......
263: Tube DIY Asylum, RE: How do I SAFELY measure output impedance of a tube preamp? (0.00)
Posted by Triode_Kingdom on 2023-05-16, 09:39:40 (24.27.41.140)
Why go to that trouble? You can calculate it at the link below. .......
264: Tubes Asylum, Have to Disagree (0.00)
Posted by Triode_Kingdom on 2023-05-15, 11:17:16 (24.27.41.140)
"Some people say that only AC heating of direct heated triodes sounds good and that DC heating does not sound good. I think the people that say that have listened to amplifiers where the direct heated .......
265: Vintage Asylum, RE: It took some digging, but I finally found my parts unit (0.00)
Posted by Triode_Kingdom on 2023-05-09, 19:17:48 (24.27.41.140)
Just to interject something you might not know - You will need exactly the right tool to adjust that transformer. The slugs crack very easily if the tool isn't a perfect fit. Once they crack, that's i .......
266: Vintage Asylum, RE: "Seems odd that only Marantz part numbers are listed" (0.00)
Posted by Triode_Kingdom on 2023-05-07, 19:43:50 (24.27.41.140)
All the companies used their own part numbers on non-generic components. Your best bet is to determine the exact function of the coil/transformer and try to find an equivalent in something else. Many .......
267: Tubes Asylum, RE: Melody Sp8/3 or whatever they call it (0.00)
Posted by Triode_Kingdom on 2023-05-07, 08:46:58 (24.27.41.140)
What was the question? .......
268: SET Asylum, RE: SET Amp Sweet Spot (0.00)
Posted by Triode_Kingdom on 2023-05-05, 10:58:36 (24.27.41.140)
It seems to me that defining the audible effect of distortion in each particular case is a tough call. So, I prefer to push it down to levels that I hope won't be audible and go with that. One can alw .......
269: SET Asylum, RE: SET Amp Sweet Spot (0.00)
Posted by Triode_Kingdom on 2023-05-03, 16:12:00 (24.27.41.140)
There's no sweet spot in a Class A SET in terms of signal amplitude. Distortion simply increases as the volume is turned up. .......
270: Tube DIY Asylum, RE: That could work (0.00)
Posted by Triode_Kingdom on 2023-05-02, 14:39:04 (24.27.41.140)
Let me kn ow how that works out. Could be a real revolution in the service industry! .......
271: Tube DIY Asylum, RE: "a bunch of resistors (carbon comp.)" (0.00)
Posted by Triode_Kingdom on 2023-05-02, 10:21:04 (24.27.41.140)
Maybe just put them in the oven every time your wife bakes a cake. :) .......
272: Tube DIY Asylum, RE: Help with Resistors and Capcitors (0.00)
Posted by Triode_Kingdom on 2023-05-01, 15:53:18 (24.27.41.140)
So many questions, so little time... :) I use carbon composition resistors for grid and screen stoppers. They are better at this than any other type, because they are non-inductive. Also, the fact tha .......
273: Vintage Asylum, RE: Caps are new to me also... (0.00)
Posted by Triode_Kingdom on 2023-04-26, 14:21:57 (24.27.41.140)
The caps are claimed to be polyester film, not paper. That's a nice amp! .......
274: Tubes Asylum, RE: symbol (0.00)
Posted by Triode_Kingdom on 2023-04-26, 14:18:31 (24.27.41.140)
Looks like it's supposed to be a 10uF polarized capacitor. No idea what the voltage rating should be. .......
275: Vintage Asylum, AES OIL Caps (0.00)
Posted by Triode_Kingdom on 2023-04-25, 23:39:09 (24.27.41.140)
"surprising that they only carry the 50V version" They also carry 600V. Wish I knew more about this line. .......
276: Vintage Asylum, RE: Who makes this capacitor ? (0.00)
Posted by Triode_Kingdom on 2023-04-24, 23:04:40 (24.27.41.140)
Antique Electronic Supply sells those. Don't know the actual manufacturer or where they're made. PDF Datasheet: https://www.tubesandmore.com/sites/default/files/associated_files/c-mod-x-50.pdf ::: TOP .......
277: Tube DIY Asylum, RE: Instrument harmonics aren't -60 dBC (nt) (0.00)
Posted by Triode_Kingdom on 2023-04-22, 21:46:01 (24.27.41.140)
"The third is almost as loud as the fundamental." That was my point. It was a ridiculous comparison and totally irrelevant (as I said below). .......
278: Vintage Asylum, ASR-110/120 (0.00)
Posted by Triode_Kingdom on 2023-04-21, 10:07:04 (24.27.41.140)
I pulled the push-pull OPTs from an ASR-120 years ago. Still haven't decided what to do with them. The power trans is powering a 2x EL34 guitar amp. Never knew they made an ASR-110 on the same chassis .......
279: Tube DIY Asylum, Only to you (nt) (0.00)
Posted by Triode_Kingdom on 2023-04-20, 19:39:35 (24.27.41.140)
nada aqui .......
280: Tube DIY Asylum, Still not relevant (0.00)
Posted by Triode_Kingdom on 2023-04-19, 22:38:47 (24.27.41.140)
"Switch to square wave and turn up the volume" Just like your mention of instrument timber, this isn't even remotely connected to what I said. My skepticism is directed at the higher order harmonics p .......
281: Tube DIY Asylum, Looks terrific! (0.00)
Posted by Triode_Kingdom on 2023-04-19, 06:07:10 (24.27.41.140)
I've often thought about "outside the box" chassis designs, but it always entails custom metal work I can't produce on my own. Great job on this project! .......
282: Tube DIY Asylum, Nice work! (0.00)
Posted by Triode_Kingdom on 2023-04-19, 06:02:15 (24.27.41.140)
There's something very satisfying about building one's own test gear. Congrats! .......
283: Tube DIY Asylum, No, I simply don't believe it's relevant (0.00)
Posted by Triode_Kingdom on 2023-04-18, 20:07:12 (24.27.41.140)
"do you think that when a distortion component is below a certain dB level, that it does not alter the waveform??" I think any attempt to characterize the sound of an amplifier on the basis of a harmo .......
284: Tube DIY Asylum, Yeah, that must be it (0.00)
Posted by Triode_Kingdom on 2023-04-17, 21:48:35 (24.27.41.140)
It's clear now that you're just making this up as you go along. The tonal qualities of instruments are created by huge harmonics much greater in amplitude than the levels Crowhurst was discussing. Yes .......
285: Tube DIY Asylum, Instrument harmonics aren't -60 dBC (nt) (0.00)
Posted by Triode_Kingdom on 2023-04-17, 10:40:22 (24.27.41.140)
nada aqui .......
286: Tube DIY Asylum, RE: Audio Magazine article PP 300B amp (0.00)
Posted by Triode_Kingdom on 2023-04-15, 19:44:48 (24.27.41.140)
"...there were no high-end audio systems." Well, there was at least one. The amplifier in the article produced "excellent wave form at forty watts output, particularly at the ends of the range we wish .......
287: Tube DIY Asylum, RE: Apples and oranges (0.00)
Posted by Triode_Kingdom on 2023-04-14, 09:00:34 (24.27.41.140)
You may have noticed that the smaller SETs sound better than the bigger ones. Not in my experience. It's a mixed bag, likely because (as you say), execution is everything. Even way back then, Norma .......
288: Tubes Asylum, RE: Once was lost, now is found... (0.00)
Posted by Triode_Kingdom on 2023-04-11, 22:49:52 (24.27.41.140)
Sounds like those speaker drivers and transformers are quite a nuisance. I can help with that, no charge to an Asylum member. :) .......
289: Tube DIY Asylum, RE: Apples and oranges (0.00)
Posted by Triode_Kingdom on 2023-04-11, 15:36:00 (24.27.41.140)
Comparing watt-for-watt doesn't "even the playing field," any more than if one considers high(er) efficiency speakers. Power ratings are not the issue, unless of course one is forced into that corner .......
290: Tube DIY Asylum, RE: Impossible is a stretch (0.00)
Posted by Triode_Kingdom on 2023-04-07, 15:42:19 (24.27.41.140)
"I was able to do it on my first try designing a transformer coupled PP amplifier." Sorry, what exactly did you do? Not all amps that measure better, sound better. There's more to sound quality than T .......
291: Tube DIY Asylum, SETs (0.00)
Posted by Triode_Kingdom on 2023-04-07, 09:37:24 (24.27.41.140)
"That design really convinced me about why SETs went the way decades ago. " SETs were shelved commercially because of horsepower wars, not sound quality. My main amp for many years was a 3W/ch 6V6 SEP .......
292: Tube DIY Asylum, Restored 70's receivers - Pipe Dream (0.00)
Posted by Triode_Kingdom on 2023-04-07, 09:24:30 (24.27.41.140)
Most can't really be restored. The worn-out switches and controls that are so common to those older units are unavailable. The same is true for vintage tube receivers and integrated amps, which is the .......
293: Tube DIY Asylum, RE: Fisher 600 tube transformers (0.00)
Posted by Triode_Kingdom on 2023-04-05, 08:29:59 (24.27.41.140)
I've noticed the same thing regarding my HK receivers and amps in storage. One of them donated its iron to a 6L6-based power amp, but now I'm wondering if it might be smarter to just sell the others. .......
294: Tube DIY Asylum, Do they clip softly? (0.00)
Posted by Triode_Kingdom on 2023-04-03, 18:44:18 (24.27.41.140)
And do they exhibit the same signature while clipping? Don't know anything about them, but these are relevant characteristics for comparison. .......
295: Tubes Asylum, RE: Come on.... (0.00)
Posted by Triode_Kingdom on 2023-04-03, 11:10:18 (24.27.41.140)
Maybe the tubes are developing a higher internal resistance and the damping factor is degrading. Of course, that wouldn't be "better" bass, just more poor quality bass. Whatever you guys are hearing, .......
296: Vintage Asylum, Agree (0.00)
Posted by Triode_Kingdom on 2023-04-02, 17:35:47 (24.27.41.140)
From my experience back in the day, he will need the diagram that's (hopefully) in the service manual. Dial cord stringing can be very confusing, and it's not likely a photograph will be sufficient. .......
297: Tubes Asylum, RE: Follow-up on new build ST-70 with the 6NS7 tube (0.00)
Posted by Triode_Kingdom on 2023-04-01, 18:16:42 (24.27.41.140)
"in what applications does the 12AU7 most impact performance and least impact performance?" Most Impact: When used as a standard gain stage in a circuit with no local or global feedback. Least Impact: .......
298: Tube DIY Asylum, RE: DIY Tube Amps Dying (0.00)
Posted by Triode_Kingdom on 2023-03-30, 22:02:24 (24.27.41.140)
I suspect cheap Chinese amps and preamps - not to mention the ever-increasing cost of good quality chassis and electrical parts from the West - has taken a big bite out of this sector. There may be ot .......
299: Tube DIY Asylum, RE: It's not always so simple (0.00)
Posted by Triode_Kingdom on 2023-03-30, 21:56:54 (24.27.41.140)
That's a pretty good analysis. Still, these caps may not exhibit the value expected in circuits with significant DC voltage. And the mere fact that their use is limited to certain purposes renders the .......
300: Tubes Asylum, RE: Link? (0.00)
Posted by Triode_Kingdom on 2023-03-30, 15:51:46 (24.27.41.140)
You want a link to prove that tubes wear out? .......
301: Tubes Asylum, RE: All I know... (0.00)
Posted by Triode_Kingdom on 2023-03-29, 22:18:39 (24.27.41.140)
There may or may not be an objective reason for the difference you believe you're hearing, but tubes do not produce "better" bass with age. That's a fact. .......
302: Tube DIY Asylum, RE: Sad News : Mike LaFevre / Magnequest has Passed Away (0.00)
Posted by Triode_Kingdom on 2023-03-27, 15:37:18 (24.27.41.140)
Very sorry to hear this. It's such a shame he was never able to find someone he could mentor. His passing is a loss for everyone. .......
303: Vintage Asylum, Nothing you can apply will restore the plasticizers (nt) (0.00)
Posted by Triode_Kingdom on 2023-03-25, 19:42:17 (24.27.41.140)
nada aqui .......
304: Tubes Asylum, Nothing worse than tubes that are breakin (0.00)
Posted by Triode_Kingdom on 2023-03-25, 19:40:17 (24.27.41.140)
"Bass is starting to come in now which at first was very thin/weak." Sorry, but you're hearing what you want to hear. There is not even one documented case of a tube providing more bass as it ages. : .......
305: Tube DIY Asylum, RE: Connecting headphones to SET amp (0.00)
Posted by Triode_Kingdom on 2023-03-25, 10:28:33 (24.27.41.140)
I would never connect headphones directly to the output of a power amp. There's just too much risk of hearing damage. Even my little 6V6 SEPs have a resistive attenuator network for this. ::: TOPIC:: .......
306: Tubes Asylum, eBay Policies Generally Assist Him in Hiding Fraud (0.00)
Posted by Triode_Kingdom on 2023-03-23, 12:20:03 (24.27.41.140)
The upside to eBay is that items that are "not as described" can usually be returned at the seller's expense. However, if a transaction is cancelled for almost any reason, including this, the buyer is .......
307: Tube DIY Asylum, Disc Ceramic (0.00)
Posted by Triode_Kingdom on 2023-03-19, 11:37:43 (24.27.41.140)
There is an issue with ceramic caps, although I'm not sure the extent to which this applies to the older discs. When voltage is applied to a modern multilayer ceramic cap, its capacitance changes. The .......
308: Tube DIY Asylum, RE: And the caution goes for resistors sometimes too (0.00)
Posted by Triode_Kingdom on 2023-03-19, 11:25:20 (24.27.41.140)
Your philosophy for the use of carbon comps is valid, but I'm not sure that article is credible. For one thing, all the old carbon composition resistors in my stock that are out of tolerance have drif .......
309: Tube DIY Asylum, RE: Q: Citation2 Build-Huge Phase Inverter DC Balance Runaway (0.00)
Posted by Triode_Kingdom on 2023-03-18, 09:16:23 (24.27.41.140)
You're correct, the grids are elevated. However, they're connected together for DC, and the same is true for the cathodes. If anode voltages are significantly different, either the circuit is wired in .......
310: Tubes Asylum, RE: PSA Bad ebay seller anthonybrian23 AVOID! (0.00)
Posted by Triode_Kingdom on 2023-03-17, 20:49:30 (24.27.41.140)
Well, don't think you're the only one. I was taken for the cost of a group of 211 tubes in the early days. It was before eBay had their current policy protecting buyers, and in fact, PayPal told me at .......
311: Tubes Asylum, RE: PSA Bad ebay seller anthonybrian23 AVOID! (0.00)
Posted by Triode_Kingdom on 2023-03-17, 18:04:38 (24.27.41.140)
"anyone taking the BIN and paying through ebay would have received the same outcome" No, a BIN is protected and can be returned for a refund if it's not as described. I think you already know this. Ho .......
312: Tubes Asylum, RE: PSA Bad ebay seller anthonybrian23 AVOID! (0.00)
Posted by Triode_Kingdom on 2023-03-17, 09:03:51 (24.27.41.140)
"he refused to do the right thing and make it right and ultimately made off with my money" Why didn't you return it? You don't need the seller's permission to do that. .......
313: Tube DIY Asylum, RE: Q: Citation2 Build-Huge Phase Inverter DC Balance Runaway (0.00)
Posted by Triode_Kingdom on 2023-03-17, 08:55:33 (24.27.41.140)
The long tailed pair inverter connects both cathodes together, and both grids are at DC ground through the 1M resistors. This means the tubes are biased identically and should draw more or less the sa .......
314: Tubes Asylum, RE: AT 7 help (0.00)
Posted by Triode_Kingdom on 2023-03-08, 12:38:27 (24.27.41.140)
Tubes have scientific characteristics. "Musical" and "three-dimensional" aren't on the list. Have you made any measurements, such as distortion? Maybe the original tubes were simply worn out, and perf .......
315: Tubes Asylum, RE: Genelex KT66 price (0.00)
Posted by Triode_Kingdom on 2023-03-05, 17:53:44 (24.27.41.140)
What I said is that 807s and 1625s were 50¢ on the surplus market in the '60s. I know, because I was buying them for my ham radio hobby with money I earned working after school. .......
316: Tubes Asylum, RE: I do too (0.00)
Posted by Triode_Kingdom on 2023-03-04, 14:20:38 (24.27.41.140)
I'm not buying them now either, but I do occasionally think about Russian tubes being sold out of Ukraine. Wish I knew more about that situation. .......
317: Tube DIY Asylum, RE: Yes Indeed! (0.00)
Posted by Triode_Kingdom on 2023-03-03, 16:00:22 (24.27.41.140)
Well, I personally find the UP concept to be flawed and of no value. If I were forced to use it, perhaps in order to market a product, I would probably do the same as John. Cancellation is bound to be .......
318: Vintage Asylum, Doesn't look like it (0.00)
Posted by Triode_Kingdom on 2023-03-03, 08:10:26 (24.27.41.140)
Nothing in the documentation or the description of the AJ-41 indicates that it's capable of simulcast. The Stereo position on the Mode selector is FM MPX only. .......
319: Vintage Asylum, RE: True, but some of the separate AM and FM tuner, umm, tuners had MPX stereo, too (0.00)
Posted by Triode_Kingdom on 2023-03-02, 16:20:47 (24.27.41.140)
A number of companies offered receivers with separate tuners. I don't recall any offering simulcast output plus FM MPX, unless it was a model with the MPX offered as an option. HK did that for a short .......
320: Tubes Asylum, RE: Genelex KT66 price (0.00)
Posted by Triode_Kingdom on 2023-03-02, 11:06:24 (24.27.41.140)
I started playing with vacuum tubes in the '60s. If only I had known then what I know now. I still remember being given a frequency meter the size of a small refrigerator that was loaded with 45s. Bac .......
321: Tubes Asylum, RE: tube sales (0.00)
Posted by Triode_Kingdom on 2023-03-02, 11:00:22 (24.27.41.140)
Sorry to hear this, can't imagine what you've been through. My suggestion is to list the tubes in the AudioAsylum Trader and either state an asking price or take offers. Just make it clear you don't w .......
322: Vintage Asylum, RE: AM/FM simulcast stereo radio (0.00)
Posted by Triode_Kingdom on 2023-03-02, 10:53:36 (24.27.41.140)
Harman Kardon also made a number of stereo receivers based on this format. AM in one channel - FM in the other. I wonder how many eBay buyers have been fooled into thinking they were bidding on a ster .......
323: Tube DIY Asylum, Yes Indeed! (0.00)
Posted by Triode_Kingdom on 2023-03-02, 10:47:47 (24.27.41.140)
That's a masterpiece, thanks for the link! John Broskie may be the only online resource I have never had reason to doubt (and there are a large number of well-respected authors and engineers on the ot .......
324: Vintage Asylum, RE: Altec 886A Rehab (0.00)
Posted by Triode_Kingdom on 2023-02-28, 14:32:31 (24.27.41.140)
Using an amplifier that's too small can damage that cone tweeter when the amplifier clips. I would clean the switch like the other poster said, but if that doesn't fix it, you might need to replace th .......
325: Vintage Asylum, RE: HK Citation II capacitor life. (0.00)
Posted by Triode_Kingdom on 2023-02-28, 08:51:32 (24.27.41.140)
Just my opinion - When they hit the 20 year mark, it's probably a good idea to test for ESR, capacitance and leakage. I would replace them at 30 years to ensure good performance and to avoid any nasty .......
326: Tube DIY Asylum, RE: Are the magnetics chinese or Canadian? (nt) (0.00)
Posted by Triode_Kingdom on 2023-02-21, 12:42:03 (24.27.41.140)
The last transformer I needed was for a small bias supply. Hammond was Chinese, so was Triad. I ended up buying Signal. It's not US made, but at least not Chinese. .......
327: SET Asylum, RE: Sorry, no (0.00)
Posted by Triode_Kingdom on 2023-02-18, 19:28:52 (24.27.41.140)
OK, thanks just the same. I've been trying to compile some typical numbers, but it's not easy. Many of the manufacturers are less than totally transparent on this issue. :) .......
328: SET Asylum, RE: What's your favorite 845 tube? (0.00)
Posted by Triode_Kingdom on 2023-02-16, 20:26:36 (24.27.41.140)
Have you ever measured the distortion of your amps with any of the various 845s? My 211 SETs are almost complete, and I'm curious what others see with large triodes like this. .......
329: Tube DIY Asylum, RE: New tax laws are NOT helping tube sales... (0.00)
Posted by Triode_Kingdom on 2023-02-14, 12:47:13 (24.27.41.140)
Western economies are in a downward spiral. I'm sure the new theft rules you're referring to are just the tip of the iceberg. Buckle up! .......
330: Vintage Asylum, RE: Anode Follower VS Cathode Follower Hiss Madness (0.00)
Posted by Triode_Kingdom on 2023-02-13, 21:54:16 (24.27.41.140)
Jim McShane has posted good advice above for lowering the noise floor of the Citation I. Still, an amplifier capable of 60W output with 1.5V input has grater gain than a 10W amplifier with the same se .......
331: Vintage Asylum, RE: Anode Follower VS Cathode Follower Hiss Madness (0.00)
Posted by Triode_Kingdom on 2023-02-13, 15:07:02 (24.27.41.140)
"I am using a very high sensitivity speaker," This, plus the lack of amplifier level controls, is likely the problem. The anode follower is probably contributing, because it will output more "last sta .......
332: SET Asylum, RE: Because.... (0.00)
Posted by Triode_Kingdom on 2023-02-13, 08:23:33 (24.27.41.140)
If a member of the Asylum was local to me, I might be willing to take on a small project for free. That's especially likely if my part of the job would only involve troubleshooting. OTOH, I'm not inte .......
333: Tubes Asylum, RE: Amperex BB EL84 - Circular mica slice purpose? (0.00)
Posted by Triode_Kingdom on 2023-02-13, 08:15:36 (24.27.41.140)
Not that I have an answer, but which pins are those? .......
334: Tube DIY Asylum, RE: Build a Power Supply for a McIntosh C8 pre-amp? (0.00)
Posted by Triode_Kingdom on 2023-02-11, 23:41:27 (24.27.41.140)
Interesting that they used a half-wave doubler. In any event, DC will certainly provide a lower noise floor, especially in the phono section. Copying the Dynaco PS appears to be the most straightforwa .......
335: Tube DIY Asylum, RE: Build a Power Supply for a McIntosh C8 pre-amp? (0.00)
Posted by Triode_Kingdom on 2023-02-11, 09:35:17 (24.27.41.140)
The original power supply design leaves something to be desired. It was OK when tubes were cheap and could be hand-selected for acceptable performance, but you can do better. It would be beneficial to .......
336: Tube DIY Asylum, RE: In a conventional tradition tube amp this would be easy to do. (0.00)
Posted by Triode_Kingdom on 2023-02-09, 12:36:03 (24.27.41.140)
I currently have an opamp-based distortion test adapter breadboarded on my bench pending final construction. It will allow me to measure distortion in high-Z stages with large pk-pk voltage swings. Af .......
337: Tube DIY Asylum, RE: You should try it (0.00)
Posted by Triode_Kingdom on 2023-02-08, 16:20:18 (24.27.41.140)
The key word was "significant." It's just not clear to me where this falls in the big picture. It might be night and day, or it might be something none of us can hear. Point noted that your amps requi .......
338: Tube DIY Asylum, RE: Norman Crowhurst (0.00)
Posted by Triode_Kingdom on 2023-02-07, 22:51:48 (24.27.41.140)
"if you linearize the feedback node you'll get less of these effects." I don't disagree with that, but it's not clear to me that this statement is sufficient to validate a claim to a significant benef .......
339: Tube DIY Asylum, RE: Build a Power Supply for a McIntosh C8 pre-amp? (0.00)
Posted by Triode_Kingdom on 2023-02-06, 20:55:24 (24.27.41.140)
The D8 is included in the schematic you linked (for SN 10600 and up): .......
340: Tube DIY Asylum, RE: Why would the input tube appear to be more linear (0.00)
Posted by Triode_Kingdom on 2023-02-06, 20:35:51 (24.27.41.140)
Just to be clear, you're saying that for a given amount of NFB (dB), the resistive mixing ahead of the grid produces improved IM and less upper harmonic energy compared to injection at the cathode. Is .......
341: Tube DIY Asylum, RE: Speed and Clarity (0.00)
Posted by Triode_Kingdom on 2023-02-06, 20:28:28 (24.27.41.140)
"Amp without NFB is fastest response and highest clarify" Western Electric didn't think so. But like anything else, it has to be done "right." .......
342: Tube DIY Asylum, RE: Speed and Clarity (0.00)
Posted by Triode_Kingdom on 2023-02-04, 23:24:30 (24.27.41.140)
"But SET amps are asymmetrical" How does that relate to the claim that NFB degrades speed and clarity? .......
343: Tube DIY Asylum, RE: Feedback is usually misapplied. You might want to try this (0.00)
Posted by Triode_Kingdom on 2023-02-03, 16:47:56 (24.27.41.140)
"Usually feedback in a tube amp is connected to the cathode of the input tube. The tube isn't linear although it might be 'fairly linear'. As a result the feedback signal gets distorted before it can .......
344: SET Asylum, RE: Fi X4 Repair (0.00)
Posted by Triode_Kingdom on 2023-02-02, 11:51:40 (24.27.41.140)
If you add the city/state to your profile, someone nearby might chime in. Maybe a long shot, but you never know. Many of us here have well-equipped tech benches and are competent in what we do. I'd of .......
345: Tube DIY Asylum, Speed and Clarity (0.00)
Posted by Triode_Kingdom on 2023-02-02, 09:30:24 (24.27.41.140)
"the zero NFB amp has mush faster speed and clarity" My 211 SETs include about 5dB NFB. Frequency response at -1dB extends to 40kHz. How much faster do they need to be? .......
346: SET Asylum, RE: Fi X4 Repair (0.00)
Posted by Triode_Kingdom on 2023-02-01, 21:29:43 (24.27.41.140)
I hate to sound grouchy, but why do people post things like this without telling anyone where they're located? It just doesn't make sense. .......
347: Tube DIY Asylum, RE: NFB in a PP DHT amp? (0.00)
Posted by Triode_Kingdom on 2023-01-30, 07:04:31 (24.27.41.140)
"I have found the output Z reduction the most important benefit about NFB." ^^^^ This! NFB will also increase output power at the onset of distortion at low frequencies. The increase can be significan .......
348: Tube DIY Asylum, RE: It's nice to be alive and 75 but it comes at a cost (0.00)
Posted by Triode_Kingdom on 2023-01-17, 15:23:05 (24.27.41.140)
You could have a rectangular bezel cut and engraved. The bezel could hold the power switch and a pilot lamp or LED. FWIW, my Citation V has no power switch. Didn't want to modify the amp, so I use a s .......
349: Tube DIY Asylum, 12AU7 (0.00)
Posted by Triode_Kingdom on 2023-01-16, 10:01:58 (24.27.41.140)
The best subs for this in the ST-70 are the 6SN7 and 6CG7. Some of the aftermarket boards are made for these, but you can also buy adapters. .......
350: Tube DIY Asylum, RE: I know the feeling! (0.00)
Posted by Triode_Kingdom on 2023-01-10, 11:15:14 (24.27.41.140)
It is possible to design an amplifier with SS components that sounds good. The problem is, it's easier to design one that doesn't, and that represents the majority of products on the market, even goin .......
351: Tube DIY Asylum, Ping: Paul Joppa (0.00)
Posted by Triode_Kingdom on 2023-01-06, 22:48:31 (24.27.41.140)
Paul, we spoke briefly some time back about the Magnequest FS-100 transformers I'm using. The amplifiers are finished now, and I would appreciate a chance to briefly discuss a problem I'm seeing. Woul .......
352: Tubes Asylum, One of the best, and he'll be missed! (0.00)
Posted by Triode_Kingdom on 2023-01-04, 13:56:21 (24.27.41.140)
I'm glad to see Jim will continue to support vintage restorations, such as the HK Citation series. Between Covid, the Ukraine invasion, super inflation and Made in China, this hobby and the tube indus .......
353: Tube DIY Asylum, RE: New amp (0.00)
Posted by Triode_Kingdom on 2023-01-02, 13:06:59 (24.27.41.140)
Sure. I think about front ends sometimes. .......
354: Tube DIY Asylum, RE: squeaky tube (0.00)
Posted by Triode_Kingdom on 2023-01-02, 13:05:45 (24.27.41.140)
You could try cleaning the tube socket with a bit of DeOxit. To avoid making a mess inside the unit, I would spray the pins of the tube and insert it two or three times. You might also try to re-tensi .......
355: Tube DIY Asylum, RE: minimum load current (0.00)
Posted by Triode_Kingdom on 2023-01-02, 10:50:18 (24.27.41.140)
In that case, I would replace the LM317. The output noise spec is well under 1mV, and ripple rejection should be at least 66dB (0.0005 X input ripple). If the replacement does the same, I would suspec .......
356: Tube DIY Asylum, RE: LM317 Regulator (0.00)
Posted by Triode_Kingdom on 2023-01-01, 23:24:16 (24.27.41.140)
The data sheet states that the minimum load current to maintain regulation is 3.5mA typical and 10mA maximum. Maybe adding a 390Ω resistor across the output will help. .......
357: Vintage Asylum, Classic Mis-communication (0.00)
Posted by Triode_Kingdom on 2022-12-31, 20:50:35 (24.27.41.140)
"If you only get one channel with the mono button pressed in..." Pretty sure he meant the opposite of that. It was an entirely ambiguous description: " I only get sound from the right channel when I .......
358: Tube DIY Asylum, Followup (Solution) (0.00)
Posted by Triode_Kingdom on 2022-12-30, 14:10:54 (24.27.41.140)
" I ordered the Eclipse extractor with an ID of 0.122" today. If it works, I'll follow up here. " The Eclipse tool never arrived. The seller gave me a BS explanation that could have kept me waiting mo .......
359: Tube DIY Asylum, RE: a patentable concept is (0.00)
Posted by Triode_Kingdom on 2022-12-27, 07:40:45 (24.27.41.140)
Even if I were to concede the point about the impracticality of defining "maximum linearity" for legal purposes, it wouldn't explain why a KT-88 manufacturer would post curves indicating poor tube per .......
360: Tube DIY Asylum, RE: UL Distortion (0.00)
Posted by Triode_Kingdom on 2022-12-25, 07:30:51 (24.27.41.140)
Are you referring to "An Ultra-Linear Amplifier," by Hafler and Keroes? I can appreciate the technical aspects presented in that article. However, the testing (and particularly the authors' conclusion .......
361: Tube DIY Asylum, RE: Right. (0.00)
Posted by Triode_Kingdom on 2022-12-24, 11:16:10 (24.27.41.140)
I don't see how "positioning the tap to maximize linearity" is a patentable concept. "Maximum" is an infinitely small point, and the tiniest difference in linearity (perhaps so small a difference it c .......
362: Tubes Asylum, RE: MC240 125V switch question (0.00)
Posted by Triode_Kingdom on 2022-12-23, 19:18:38 (24.27.41.140)
I would just try to match the nominal input voltage setting to what you have available to power the amplifier. I would not attempt to intentionally power the amplifier with significantly less. ::: TO .......
363: Tube DIY Asylum, RE: No. UL was patented. So (0.00)
Posted by Triode_Kingdom on 2022-12-23, 19:06:59 (24.27.41.140)
Are you saying the UL patent only covers the use of a single, specific tap point? I don't see that referenced in the link you provided. .......
364: Tube DIY Asylum, UL Distortion (0.00)
Posted by Triode_Kingdom on 2022-12-23, 10:26:33 (24.27.41.140)
A gentleman on another forum recently posted this graph showing these terrible-looking UL curves for the KT-88. Is this typical of UL operation for other tubes as well, such as the EL34? Maybe this is .......
365: Tubes Asylum, RE: MC240 125V switch question (0.00)
Posted by Triode_Kingdom on 2022-12-21, 21:30:12 (24.27.41.140)
The schematic shows a center-tapped winding on the power transformer that is connected to the "Preamp power" plug. I assume this winding is filament power, however, it's not connected to any of the tu .......
366: Tubes Asylum, RE: Japanese tubes, especially the EL34 made with Mullard tooling. IS there. . (0.00)
Posted by Triode_Kingdom on 2022-12-17, 06:38:53 (24.27.41.140)
"Japanese EL34s NOS that look a lot like Mallards," You know what they say - If it looks like a duck, walks like a duck and quacks like a duck... Sorry, couldn't resist. .......
367: Tube DIY Asylum, It's been done (0.00)
Posted by Triode_Kingdom on 2022-12-13, 14:27:28 (24.27.41.140)
Audiovox made a car audio amplifier like that many years ago. Instead of a DC-DC power supply to increase output power, it relied on the output transformer ratio. .......
368: Tubes Asylum, RE: Tube for a Mac 1500 (0.00)
Posted by Triode_Kingdom on 2022-12-10, 21:06:44 (24.27.41.140)
Characteristics of the 12AX7 will be audible, but bear in mind it's inside the global loop. Its contribution will be diminished because of that. The 12AU7 will have almost no effect. It's inside the l .......
369: Vintage Asylum, RE: Interesting. Have you used it yet? (0.00)
Posted by Triode_Kingdom on 2022-12-09, 21:02:38 (24.27.41.140)
It's only zero distortion if it A) doesn't have the optional cathode follower output stage and B) you don't use the phono input. All the control circuitry is passive. .......
370: Tube DIY Asylum, Maybe ask the mods to delete this thread. (nt) (0.00)
Posted by Triode_Kingdom on 2022-12-08, 19:26:02 (24.27.41.140)
nada aqui .......
371: Tubes Asylum, RE: and here is (0.00)
Posted by Triode_Kingdom on 2022-12-08, 13:02:55 (24.27.41.140)
The reissues are all beam power, as far as I know. That would mean they draw less screen current than a pentode. If the circuit in your amplifier relies on the exact screen current to determine screen .......
372: Tube DIY Asylum, RE: Hi B+ on Morrison Micro (0.00)
Posted by Triode_Kingdom on 2022-12-08, 12:55:25 (24.27.41.140)
I would suggest that you delete this and post it on the SET forum (but don't cross post). There are also a lot of SET enthusiasts (including a Bottlehead employee) on the tube gear forum at HiFi Haven .......
373: Tube DIY Asylum, RE: output transformers (0.00)
Posted by Triode_Kingdom on 2022-12-06, 21:11:01 (24.27.41.140)
That's the appropriate impedance for two EL34s per channel. .......
374: Vintage Asylum, RE: Did you mean CDP-CX355? (I have one) (0.00)
Posted by Triode_Kingdom on 2022-12-06, 14:19:30 (24.27.41.140)
I have no idea how the Sony SACD players perform with standard discs. They might be better or worse than a deck designed solely for that. The primary disadvantage to this machine is its size. It reall .......
375: Vintage Asylum, Did you mean CDP-CX355? (I have one) (0.00)
Posted by Triode_Kingdom on 2022-12-04, 23:23:16 (24.27.41.140)
I bought it new at Fry's years ago, just before it was discontinued. Pretty sure it was the last Sony carousel model that wasn't made in China. This one needed new belts about four years ago. The belt .......
376: Tube DIY Asylum, Agree (0.00)
Posted by Triode_Kingdom on 2022-12-04, 18:47:35 (24.27.41.140)
SendCutSend made the large bottom plates for my SETs. Excellent quality. .......
377: Tube DIY Asylum, RE: Output transformers (0.00)
Posted by Triode_Kingdom on 2022-12-04, 18:46:08 (24.27.41.140)
He needs about 2K plate-to-plate for four EL34s. .......
378: Tubes Asylum, Thank you!! (0.00)
Posted by Triode_Kingdom on 2022-12-04, 06:52:17 (24.27.41.140)
Vey nice of you to take the time to do this! .......
379: Tube DIY Asylum, RE: Sylvania application notes (0.00)
Posted by Triode_Kingdom on 2022-12-04, 06:49:44 (24.27.41.140)
There are a few interesting tidbits in the section on hum that starts on page 11. One is the recommendation of the use of non-magnetic materials for the chassis. Another point is that a tube with high .......
380: Tube DIY Asylum, RE: Output transformers (0.00)
Posted by Triode_Kingdom on 2022-12-04, 06:25:16 (24.27.41.140)
The Hammond 1650T and 1650W would work. .......
381: Tube DIY Asylum, RE: Clarification (0.00)
Posted by Triode_Kingdom on 2022-12-03, 20:18:20 (24.27.41.140)
"I sometimes need to use a dental pick or jeweler's screwdriver to squeeze the fem contact down smaller" In my experiments, it was necessary to actually curl the flare over itself slightly for the too .......
382: Tubes Asylum, RE: does this quilify as a data sheet (0.00)
Posted by Triode_Kingdom on 2022-12-03, 07:14:02 (24.27.41.140)
I read the Sylvania sheet for the early metal version 6CA7 online, and I also have the printed technical manual. Both claim this is a beam power tube, and the manual goes so far as to say "identical" .......
383: Tube DIY Asylum, Clarification (0.00)
Posted by Triode_Kingdom on 2022-12-02, 21:35:27 (24.27.41.140)
Just to clarify, is this the exact same tool you have? It's clearly the wrong size for female pins in the .093" series. It appears to have been designed solely for the male pins, which have a smaller .......
384: Tube DIY Asylum, RE: Help with Molex Pin Extractor (0.00)
Posted by Triode_Kingdom on 2022-12-02, 20:09:59 (24.27.41.140)
This tool can't be forced over the flange. The OD of the hollow tube is exactly the same as the OD of the flange. If I even went so far as to put it in a vise, it would only crush the pin. ::: TOPIC .......
385: Tube DIY Asylum, RE: Buy a better one! (0.00)
Posted by Triode_Kingdom on 2022-12-02, 20:08:16 (24.27.41.140)
Molex sells at least two tools for this. One is spring loaded, the other isn't. That doesn't look as though it has anything to do with the actual mechanics of fitment or compression of the locking tab .......
386: Tube DIY Asylum, Help with Molex Pin Extractor (0.00)
Posted by Triode_Kingdom on 2022-12-02, 16:07:12 (24.27.41.140)
Does anyone know how this tool is supposed to remove female Molex pins? It works great for male pins, but the female pins are flared at the open end. Not only will the hollow tube not fit over the fla .......
387: Tube DIY Asylum, RE: Place to get a metal plate (0.00)
Posted by Triode_Kingdom on 2022-12-02, 06:33:19 (24.27.41.140)
"Does FPE anodize?" No, and that's one of the problems with their product. The panels are pre-anodized, so everywhere FPE makes a cut - including the outer edges - it's raw aluminum. .......
388: Tubes Asylum, RE: Third Party Sources (0.00)
Posted by Triode_Kingdom on 2022-12-01, 23:01:41 (24.27.41.140)
Tre, how do we know that Sylvania adopted the same beam forming technology as the 6L6? You're correct that the metal-shell Sylvania is referred to as a beam pentode. However, in both class A and class .......
389: Tubes Asylum, Third Party Sources (0.00)
Posted by Triode_Kingdom on 2022-12-01, 12:23:21 (24.27.41.140)
Tre, those aren't data sheets, nor do they include the information necessary to determine how they were derived. Like I said elsewhere in this thread, pentodes draw more screen current than beam powe .......
390: Tubes Asylum, RE: There is truth that "fat bottle" 6CA7s are beam tetrodes not true pentodes (0.00)
Posted by Triode_Kingdom on 2022-11-30, 22:06:39 (24.27.41.140)
Do you know if there's a data sheet for this tube online? .......
391: Tubes Asylum, RE: Can someone remind me... (0.00)
Posted by Triode_Kingdom on 2022-11-30, 16:15:51 (24.27.41.140)
So, is there any truth to the claim that the 6CA7 is (or ever was) a beam power pentode? This would certainly create a problem in circuits where the screens aren't fed from a UL tap, but instead are d .......
392: Tubes Asylum, RE: Can someone remind me... (0.00)
Posted by Triode_Kingdom on 2022-11-30, 09:33:42 (24.27.41.140)
"the el34 is a pentode, 6ca7 is a beam power pentode" I've read this many times in numerous places online. However, the data sheets don't seem to support it. All the specifications I've found refer to .......
393: SET Asylum, RE: Line Magnetic LM-5081A Owners (0.00)
Posted by Triode_Kingdom on 2022-11-29, 11:00:40 (24.27.41.140)
Well, you're really shooting in the dark without a valid technical review. You can't trust people's ears for things like distortion, frequency response or output transformer performance. Audio Science .......
394: SET Asylum, RE: Line Magnetic LM-5081A Owners (0.00)
Posted by Triode_Kingdom on 2022-11-27, 14:55:54 (24.27.41.140)
Has anyone in the West published a technical review with measurements? That would be the place to start. .......
395: Tubes Asylum, RE: Vintage 7591 tubes vs Russian 6P3S or SE (0.00)
Posted by Triode_Kingdom on 2022-11-26, 08:58:28 (24.27.41.140)
"No, they have a different pin arrangement." Other issues... The 6P3S isn't suitable from a dissipation standpoint. The 6P3S-E has more than enough dissipation, but the gain is substantially lower tha .......
396: Tube DIY Asylum, RE: What is your experience in CCS load VS resistor load (0.00)
Posted by Triode_Kingdom on 2022-11-26, 07:39:14 (24.27.41.140)
CCS - tube, transistor? My 211 SETs use a 6SN7 in a totem pole arrangement with about +500V on the anode of the upper section. The filament winding is elevated to stay within specification. This can s .......
397: Tube DIY Asylum, Free Shipping (0.00)
Posted by Triode_Kingdom on 2022-11-26, 07:27:48 (24.27.41.140)
My last order to Digikey was only about $10, so I mailed the order and included a check. This only added a couple days to the turnaround time, and they shipped for free by Fedex ground. This is an exc .......
398: Tube DIY Asylum, RE: You get what you pay for (0.00)
Posted by Triode_Kingdom on 2022-11-22, 15:23:43 (24.27.41.140)
"I'm upping the impedance in the load, which will, effectively, make the 8 ohm tap look like a lower impedance, higher damping factor source" Operating the transformer at a higher impedance will cause .......
399: Tube DIY Asylum, RE: You get what you pay for (0.00)
Posted by Triode_Kingdom on 2022-11-22, 07:53:57 (24.27.41.140)
I don't know what you can expect. I don't buy Chinese audio gear. I'll just add that sparkling highs don't come from poor quality transformers. .......
400: Tube DIY Asylum, You get what you pay for (0.00)
Posted by Triode_Kingdom on 2022-11-21, 11:17:04 (24.27.41.140)
Those are useless specifications, and none of it says anything about the quality of the transformers. The latter in particular is what separates the men from the boys. .......
401: Vintage Asylum, RE: Poor opinion of Sony (0.00)
Posted by Triode_Kingdom on 2022-11-20, 11:25:13 (24.27.41.140)
Sony's claim to fame was the Trinitron, and later the Betamax. I never thought their audio gear was top notch, and that includes the reel-to-reels and receivers from the '70s. On the other hand, I pur .......
402: Tube DIY Asylum, RE: particularly in small signal applications (0.00)
Posted by Triode_Kingdom on 2022-11-20, 11:09:17 (24.27.41.140)
I would assume that the reason for this is that small signal applications generally involve higher impedances than power circuits. Higher circuit impedance renders the signals more susceptible to stra .......
403: Tube DIY Asylum, RE: Loesch circuit preamp (0.00)
Posted by Triode_Kingdom on 2022-11-18, 06:22:56 (24.27.41.140)
Interesting, there was a recent discussion on another site about low-level hum in a Tubes4hifi PH16. The owner wasn't tech savvy though, so there wasn't any real progress despite much advice. Do you w .......
404: Tube DIY Asylum, RE: Engineering is always a tradeoff. (0.00)
Posted by Triode_Kingdom on 2022-11-18, 06:08:59 (24.27.41.140)
Interesting that this insulation went from organic to inorganic. Motor vehicle wiring had done just the opposite. Now the tree rats eat it. .......
405: SET Asylum, RE: Frequency Response (0.00)
Posted by Triode_Kingdom on 2022-11-15, 06:48:24 (24.27.41.140)
That's rather insightful, Paul: "an unacknowledged motive to show how awful the frequency response and distortion was..." LOL, you're probably right, especially considering even the best tube amps wer .......
406: Tubes Asylum, I also agree (0.00)
Posted by Triode_Kingdom on 2022-11-13, 22:24:47 (24.27.41.140)
It's highly deceptive. These tubes use none of the original machinery or brand-specific engineering. .......
407: SET Asylum, RE: Frequency Response (0.00)
Posted by Triode_Kingdom on 2022-11-13, 18:22:09 (24.27.41.140)
Well, no wonder the graphs look like that. The output Z of the SET is no match for the vagaries of a LCR load. And although I realize a resistive load won't produce the same curve as a real-world spea .......
408: SET Asylum, Frequency Response (0.00)
Posted by Triode_Kingdom on 2022-11-12, 23:46:50 (24.27.41.140)
"FR graphs in the article are surprising. I'd never have thought a plot like that could come from such a good sounding amp." Those graphs don't appear to be legitimate frequency response measurements. .......
409: Tubes Asylum, RE: I hope you reported this scammer to EBay (0.00)
Posted by Triode_Kingdom on 2022-11-12, 22:31:28 (24.27.41.140)
What's really needed is an independent "eBay Counterfeits" Website. You should be able to enter an auction number and pull up any reports that have been logged against it. .......
410: Tubes Asylum, RE: Looks like it was made yesterday ~pic~ (0.00)
Posted by Triode_Kingdom on 2022-11-12, 22:28:38 (24.27.41.140)
I don't think the color of the silkscreen is one of the giveaways. I have hundreds of NOS tubes from the '40s through '60s. This includes tubes made in the US, Britain and japan. They all have white l .......
411: Tube DIY Asylum, RE: Tube bias adjustment pots upgrade or replacements... (0.00)
Posted by Triode_Kingdom on 2022-11-10, 09:00:27 (24.27.41.140)
At some point, you will need to reverse engineer a schematic for this amplifier. It's very difficult for anyone to provide meaningful advice without that. .......
412: Tube DIY Asylum, RE: What SS rectifier would you use for HT in tube amp? (0.00)
Posted by Triode_Kingdom on 2022-11-09, 21:50:52 (24.27.41.140)
My SETs use standard 1N4007 everywhere. I add a .01uF bypass across each diode in configurations where switching noise might be problematic. There's no downside to this, other than the cost of the cap .......
413: Tube DIY Asylum, And yet... (0.00)
Posted by Triode_Kingdom on 2022-11-09, 21:47:57 (24.27.41.140)
That what Jim McShane recommends for the Citation series, and that's what I use in all my doubler designs. If there's any ill effect, I can't see it, hear it or measure it. .......
414: Tube DIY Asylum, RE: Tube bias adjustment pots upgrade or replacements... (0.00)
Posted by Triode_Kingdom on 2022-11-09, 21:45:28 (24.27.41.140)
Have you tried cleaning the pots with Deoxit? If you do that, but they're still sensitive, it might be a circuit design issue. In any event, I sure wouldn't want to replace those pots without first co .......
415: Tube DIY Asylum, Beautiful work! nt (0.00)
Posted by Triode_Kingdom on 2022-11-06, 01:52:50 (24.27.41.140)
nada aqui .......
416: Tube DIY Asylum, RE: 6SN7s can drive 6AS7s quite well IME. (0.00)
Posted by Triode_Kingdom on 2022-11-01, 17:02:33 (24.27.41.140)
I would expect that. If the 6AS7 is configured as a follower, input impedance is very high due to the inherent bootstrapping of this topology. Even if it's a grounded cathode stage, gain is very low, .......
417: Tube DIY Asylum, RE: Perhaps Not the Best Approach (0.00)
Posted by Triode_Kingdom on 2022-11-01, 16:56:12 (24.27.41.140)
Well, one issue that has to be considered is the H-K limit. This isn't generally a problem if you're driving high gain pentodes in push pull. However, extreme cathode voltage swings can be needed to d .......
418: Tube DIY Asylum, RE: Perhaps Not the Best Approach (0.00)
Posted by Triode_Kingdom on 2022-10-30, 10:42:27 (24.27.41.140)
Yes, the cathode follower will help with this, but the voltage swing needed for driving an output stage presents its own set of problems. John Broskie (Tube CAD) has published a number of articles on .......
419: Tube DIY Asylum, RE: Perhaps Not the Best Approach (0.00)
Posted by Triode_Kingdom on 2022-10-29, 16:04:42 (24.27.41.140)
"So the "ideal load impedance" doesn't change even though the output impedance changed?" That's correct. Here's the important statement from the Tube CAD blog linked below: "Cathode-follower operation .......
420: Vintage Asylum, RE: Vintage 70's Japanese Receivers (0.00)
Posted by Triode_Kingdom on 2022-10-28, 09:40:14 (24.27.41.140)
I was very active in hi-fi during that era. The build and sound quality of receivers peaked in the mid- to late-'70s. The '80s saw the introduction of cheaper metal work, and integrated circuit output .......
421: Tube DIY Asylum, Perhaps Not the Best Approach (0.00)
Posted by Triode_Kingdom on 2022-10-28, 09:16:51 (24.27.41.140)
What would be the ideal load impedance for the 6080 in the usual grounded cathode mode? Whatever it is, this doesn't change just because the load is moved to the cathode. I think this project will pro .......
422: Vintage Asylum, RE: Anyone heard from Mike Samra lately? (0.00)
Posted by Triode_Kingdom on 2022-10-22, 12:45:28 (24.27.41.140)
Sorry to hear this, sounds like things have been pretty rough for you the last few years. The only thing worse than getting old is getting sick. Hope it all improves so you can get back to enjoying li .......
423: Vintage Asylum, RE: What a long, strange trip it's been (0.00)
Posted by Triode_Kingdom on 2022-10-22, 12:42:59 (24.27.41.140)
I'm sure the person I mentioned wouldn't find this to be a cost-effective solution. Glad to hear you got a refund. .......
424: Vintage Asylum, RE: What a long, strange trip it's been (0.00)
Posted by Triode_Kingdom on 2022-10-22, 09:42:38 (24.27.41.140)
Back before prices jumped, I bought a number of Harman Kardon receivers on the big auction site. Nearly all suffered shipping damage, and in particular, none of the wood cases survived. It is discoura .......
425: Tube DIY Asylum, Same here (0.00)
Posted by Triode_Kingdom on 2022-10-20, 09:53:34 (24.27.41.140)
In fact, 10 minutes would be at the outside edge of my patience. .......
426: Tube DIY Asylum, RE: Memory failure... (0.00)
Posted by Triode_Kingdom on 2022-10-19, 10:06:37 (24.27.41.140)
The power company's wording is clearly the result of careful scrutiny by lawyers. The situation is not too different here, although reimbursement is occasionally made for damaged equipment. In any eve .......
427: Tube DIY Asylum, RE: Memory failure... (0.00)
Posted by Triode_Kingdom on 2022-10-18, 23:52:04 (24.27.41.140)
That's awful. Not sure how I would deal with that, other than a bank of high-power TVS or a constant voltage transformer. I'll stop complaining about the 127V here now. .......
428: Tubes Asylum, RE: Solid State B+ (0.00)
Posted by Triode_Kingdom on 2022-10-18, 19:38:04 (24.27.41.140)
Don't forget that the voltage drop across all the resistors in the B+ line feeding driver and pre-driver tubes relies on current draw from those downstream tubes. Applying B+ when the smaller tubes ar .......
429: Tube DIY Asylum, -10% +15% (0.00)
Posted by Triode_Kingdom on 2022-10-18, 19:32:45 (24.27.41.140)
"In my area the mains is spec'd at 120V -10% +15%." Holy cow, are you sure that's correct?? 138VAC on the high end is probably a death sentence to most older tube gear. .......
430: Tubes Asylum, Solid State B+ (0.00)
Posted by Triode_Kingdom on 2022-10-16, 10:08:21 (24.27.41.140)
Quite a few manufacturers from that era used solid state supplies without issues and without a delay. You probably know this, but the reason for the delay is to prevent the application of unloaded B+ .......
431: SET Asylum, No one still alive was the first (0.00)
Posted by Triode_Kingdom on 2022-10-15, 13:47:59 (24.27.41.140)
OK, you got me, but it wasn't intended to be all that serious. None of those things I mentioned were hi-fi. Technically speaking though, no one still alive was the first to build a SET. SE triode amps .......
432: SET Asylum, What??! (0.00)
Posted by Triode_Kingdom on 2022-10-14, 21:28:29 (24.27.41.140)
Many thousands of people had SETs in the'50s and '60s. Most portable turntables were equipped with amps using a single ended 6AQ5, 50C5 or similar in each channel. .......
433: Tubes Asylum, RE: VTA Kit Amps (0.00)
Posted by Triode_Kingdom on 2022-10-14, 21:22:55 (24.27.41.140)
The thermistor is a good idea. Also, if this is a full wave center tap supply, the PIV will be about 2.8 times the DC output voltage. That means you would need at least two 1N4007 in series at each an .......
434: Tube DIY Asylum, RE: Hammond 374BX (0.00)
Posted by Triode_Kingdom on 2022-10-14, 21:15:11 (24.27.41.140)
Have you asked Hammond? No one else is really in a position to know. .......
435: Tubes Asylum, RE: VTA Kit Amps (0.00)
Posted by Triode_Kingdom on 2022-10-14, 07:06:31 (24.27.41.140)
I don't know anything about those "tube replacement" rectifiers. My choice would be to buy a couple 3A fast recovery diodes and wire them into an empty octal tube base. You don't need anything more th .......
436: Tubes Asylum, RE: VTA Kit Amps (0.00)
Posted by Triode_Kingdom on 2022-10-13, 21:14:22 (24.27.41.140)
Sell the rectifier. :) .......
437: Tubes Asylum, RE: VTA Kit Amps (0.00)
Posted by Triode_Kingdom on 2022-10-12, 23:30:21 (24.27.41.140)
"the ST120 price difference is about 280$ and includes Sovtek 6550 output tubes and 3@ 12ax7 ? Along with a rectifier tube which I'd replace with a SS recififier and TD relay....." I would grab those .......
438: Tube DIY Asylum, RE: Manley Snapper mod (0.00)
Posted by Triode_Kingdom on 2022-10-09, 18:07:15 (24.27.41.140)
I have always liked the styling of those amps. .......
439: Tubes Asylum, RE: Conrad Johnson CAV 50 tubes (0.00)
Posted by Triode_Kingdom on 2022-10-09, 14:27:40 (24.27.41.140)
For most tube types, there's no "best." There's just "different." .......
440: Vintage Asylum, RE: Yep (0.00)
Posted by Triode_Kingdom on 2022-10-06, 14:20:51 (24.27.41.140)
The impact of audio on my life has always been nothing but good. The other is a fool's errand. .......
441: Tube DIY Asylum, RE: Setting "old school" bias (0.00)
Posted by Triode_Kingdom on 2022-09-29, 12:48:14 (24.27.41.140)
You can measure the voltage from each cathode to ground, then calculate the current based on the setting of the pot. I = E ÷ R. If you're using actual 7189 tubes (not 6BQ5), the following chart shows .......
442: Tube DIY Asylum, RE: Help! I'm stumped. (0.00)
Posted by Triode_Kingdom on 2022-09-29, 01:22:52 (24.27.41.140)
Maybe it's an erroneous reading due to signal coming from the input stage. Is the grid of the output tube at ground for DC? .......
443: Tube DIY Asylum, RE: Setting "old school" bias (0.00)
Posted by Triode_Kingdom on 2022-09-29, 01:18:12 (24.27.41.140)
I just looked at the schematic. It's DC balance performed at the cathodes of the output tubes. Yes, you can replace the pot with two fixed resistors. Incidentally, that unit has a selenium rectifier f .......
444: Tube DIY Asylum, RE: Setting "old school" bias (0.00)
Posted by Triode_Kingdom on 2022-09-28, 11:30:10 (24.27.41.140)
You didn't say whether the pots for the output tubes are AC balance or DC balance. The hum pots can be replaced with fixed resistors, or maybe you could install the pots at the link below. ::: TOPIC: .......
445: Tubes Asylum, RE: scott 340 hum (0.00)
Posted by Triode_Kingdom on 2022-09-27, 21:44:51 (24.27.41.140)
The power supply outputs mostly 120 Hz. If you're seeing 60 Hz on the plates, that sounds like a different problem, something being amplified through the audio chain. Do you see this signal on the gri .......
446: Tubes Asylum, RE: scott 340 hum (0.00)
Posted by Triode_Kingdom on 2022-09-27, 16:32:43 (24.27.41.140)
Is is hum or ripple? What's the frequency? .......
447: Tube DIY Asylum, That's no reason to abuse your ears (0.00)
Posted by Triode_Kingdom on 2022-09-27, 14:28:52 (24.27.41.140)
Power is still affordable here, and I'm nearly done building a pair of monoblocks that will use a lot of it. When and if the situation changes, I'll switch to headphones and smaller tube amps. No way .......
448: Vintage Asylum, +1 nt (0.00)
Posted by Triode_Kingdom on 2022-09-26, 16:19:54 (24.27.41.140)
nada aqui .......
449: Vintage Asylum, RE: Yamaha CA-1000, CA-800, CA-2010, etc. (0.00)
Posted by Triode_Kingdom on 2022-09-26, 08:28:35 (24.27.41.140)
It's probably due to aged components, maybe capacitors that have lost value and are no longer able to "buffer" the switching transients. It's also possible the units you're seeing were already defecti .......
450: Tube DIY Asylum, RE: The wire usually connects to a ribbon of copper (0.00)
Posted by Triode_Kingdom on 2022-09-24, 09:10:09 (24.27.41.140)
An unshielded transformer will require additional consideration for noise reduction. At the very least, a small choke will be needed directly after the rectifiers as a safeguard against high frequency .......
451: Tubes Asylum, RE: What is it that makes it such a difference in tone? (0.00)
Posted by Triode_Kingdom on 2022-09-23, 09:11:33 (24.27.41.140)
Much of this is nonsense. Note the absence of objective A-B listening tests in all such discussions. .......
452: Tube DIY Asylum, RE: Where is this isolation wire connected to power transfomers? Lamination ? (0.00)
Posted by Triode_Kingdom on 2022-09-23, 06:42:46 (24.27.41.140)
I'm not an expert at transformer construction, but isn't that an electrostatic shield between the windings? If so, it's more than just a ground wire attached to the framework of the transformer. ::: .......
453: Tube DIY Asylum, It's not just the tube, it's how you use it. (0.00)
Posted by Triode_Kingdom on 2022-09-22, 23:51:34 (24.27.41.140)
Vintage designers knew how to do this. The industry now is crammed with talentless Johnny-come-lately types who don't get it. .......
454: Tube DIY Asylum, RE: Ultrasonic Filament Supplies (0.00)
Posted by Triode_Kingdom on 2022-09-22, 13:46:47 (24.27.41.140)
Looks like you need a filter cap on that line, and maybe a small choke ahead of it. .......
455: Tube DIY Asylum, RE: I'm sorry. I just had to. :-) (0.00)
Posted by Triode_Kingdom on 2022-09-22, 12:09:24 (24.27.41.140)
Yeah? Well just wait until you need solder wick. I'll show you. .......
456: Tube DIY Asylum, RE: Ultrasonic Filament Supplies (0.00)
Posted by Triode_Kingdom on 2022-09-22, 10:04:28 (24.27.41.140)
At one time, I considered designing a filter to remove all the harmonics. This would result in powering the filament with a relatively pure sine wave at the fundamental, 80 kHz or whatever. Back then, .......
457: Tube DIY Asylum, RE: Ultrasonic Filament Supplies (0.00)
Posted by Triode_Kingdom on 2022-09-22, 07:31:03 (24.27.41.140)
I hope this works for you, but I do become concerned about residual square wave energy being amplified by the low-level stages. When this signal is used only to heat the SE output tube, harmonics and .......
458: Tube DIY Asylum, Hey, that was just mean! (nt) (0.00)
Posted by Triode_Kingdom on 2022-09-22, 07:13:18 (24.27.41.140)
nada aqui .......
459: Tube DIY Asylum, RE: Converting a 12AU7 to a 6CG7 recommendations (0.00)
Posted by Triode_Kingdom on 2022-09-21, 20:43:21 (24.27.41.140)
I'm just planning ahead. 6CG7s have gone up quite a bit in price recently. If the 6AU7 works as well, and it continues to be half the price or less, then why not? Incidentally, my last amp used a 6J6 .......
460: Vintage Asylum, RE: Trouble with Fisher 400 tuner section (0.00)
Posted by Triode_Kingdom on 2022-09-21, 12:14:13 (24.27.41.140)
"Let's hold on here BEFORE you start adjusting ANY coils or variable capacitors. The problem could be purely mechanical. " This is very good advice. However, the tech did say that he attempted an elec .......
461: Tube DIY Asylum, RE: Ultrasonic Filament Supplies (0.00)
Posted by Triode_Kingdom on 2022-09-21, 11:52:06 (24.27.41.140)
I've never attempted to use these for B+. The idea does have a certain appeal, but my philosophy is generally to use as few semiconductors as possible. I make exceptions for necessity, and that was th .......
462: Tube DIY Asylum, RE: Ultrasonic Filament Supplies (0.00)
Posted by Triode_Kingdom on 2022-09-20, 19:44:54 (24.27.41.140)
My initial work with this goes back at least 15 years. I built a pair of 211 monoblocks, and I used modified "electronic transformers" to power the filaments. The use of these devices followed many un .......
463: Tube DIY Asylum, RE: Converting a 12AU7 to a 6CG7 recommendations (0.00)
Posted by Triode_Kingdom on 2022-09-20, 11:55:11 (24.27.41.140)
"Those two tubes are very similar (except the 6cg7 is a lot more linear) that I wouldn't do anything to the circuit. " Ironically, I'm about to try the exact opposite in the long tailed pair in my Cit .......
464: Vintage Asylum, RE: Trouble with Fisher 400 tuner section (0.00)
Posted by Triode_Kingdom on 2022-09-20, 10:36:28 (24.27.41.140)
There are several versions of this receiver, and I'm not sure how the various tuners compare. The schematic below is one I found. If it was me, I would start by cleaning the tuning capacitor with a pl .......
465: Tube DIY Asylum, RE: Ultrasonic Filament Supplies (0.00)
Posted by Triode_Kingdom on 2022-09-20, 09:52:54 (24.27.41.140)
This is similar in some ways, but there are distinct improvements over the previous versions. For one thing, the frequency is higher. That's due to a different oscillator transformer core in the later .......
466: Tube DIY Asylum, RE: Converting a 12AU7 to a 6CG7 recommendations (0.00)
Posted by Triode_Kingdom on 2022-09-19, 19:36:30 (24.27.41.140)
The problem changing resistors to dial in the 6CG7 is that you will also need to tune the feedback network. That requires a scope, which you previously said you don't have. V2 is cap-coupled to V1, so .......
467: Tube DIY Asylum, Ultrasonic Filament Supplies (0.00)
Posted by Triode_Kingdom on 2022-09-19, 14:57:31 (24.27.41.140)
Just finished the pair of filament supplies for my 211 SETs. These run at >80 kHz, and all the parts are commonly available and inexpensive. Need to mount them in the amps now and work up the final de .......
468: Tube DIY Asylum, RE: Who knew there was a Mouser Canada? (0.00)
Posted by Triode_Kingdom on 2022-09-19, 10:00:17 (24.27.41.140)
Does Warren own Mouser? Or just Canada? .......
469: Tubes Asylum, RE: Toobs... (0.00)
Posted by Triode_Kingdom on 2022-09-18, 14:53:45 (24.27.41.140)
Dozens of tube types can be used as followers without penalty. It's more important to set up the follower correctly than to select the perfect tube. A standard gain stage relies on the linearity of th .......
470: Tubes Asylum, RE: 6SH7 to 6J3 Questions (0.00)
Posted by Triode_Kingdom on 2022-09-16, 00:06:42 (24.27.41.140)
According to this short-form Russian data, the 6J3 is octal, and the 6J3P is a 7-pin miniature. If the Chinese versions are reversed, it would explain why the (apparently Chinese) 6J3 in the OP's unit .......
471: Tube DIY Asylum, Good to know (nt) (0.00)
Posted by Triode_Kingdom on 2022-09-13, 13:44:49 (24.27.41.140)
nada aqui .......
472: Tube DIY Asylum, "I never heard a damn bit of difference" (0.00)
Posted by Triode_Kingdom on 2022-09-13, 06:58:47 (24.27.41.140)
That's why I don't have one. The only type of conditioner I'd like to have would be a Sola CV transformer. They don't make an audible difference either, but at least the line voltage doesn't vary. :: .......
473: Tube DIY Asylum, RE: Not much (0.00)
Posted by Triode_Kingdom on 2022-09-12, 10:24:38 (24.27.41.140)
So it's basically just a power strip with an over-voltage device and RF filter? Pretty pricey for that minimum functionality. .......
474: Tube DIY Asylum, What's in it? (0.00)
Posted by Triode_Kingdom on 2022-09-11, 15:06:27 (24.27.41.140)
A "linear power conditioner" - what does that mean? Is it essentially an RF filter? .......
475: Tube DIY Asylum, RE: Measuring Arbitrary Waveforms (0.00)
Posted by Triode_Kingdom on 2022-09-09, 21:56:33 (24.27.41.140)
"Disappearing Filament Pyrometer" - LOL, I had to look that up. That would be an excellent way to do this, once correct color is determined. The simple light meter has to be physically secured so it c .......
476: Vintage Asylum, RE: Sony STR-V4 Hotrodding and now problems... (0.00)
Posted by Triode_Kingdom on 2022-09-09, 12:05:45 (24.27.41.140)
I have one of those in nearly perfect condition, although I'm not sure it still works. It's been in the closet ever since I went to tubes almost 20 years ago. Sorry I don't have any useful advice for .......
477: Tube DIY Asylum, RE: Measuring Arbitrary Waveforms (0.00)
Posted by Triode_Kingdom on 2022-09-09, 12:00:09 (24.27.41.140)
Yes, I did estimate the voltage visually before connecting it to the tube. Turns out it's difficult to be within 5% this way unless the wave is very square or very sinusoidal. It's tricky to do this w .......
478: Tube DIY Asylum, RE: Have you played with the distortion product? (0.00)
Posted by Triode_Kingdom on 2022-09-07, 16:34:51 (24.27.41.140)
My goal overall is to build circuits that perform well for their intended purpose. My time for experimentation is limited, so when an AB1 pentode amp comes in at 0.03% or 0.05% distortion, I call it g .......
479: Tube DIY Asylum, Success! (0.00)
Posted by Triode_Kingdom on 2022-09-07, 15:35:43 (24.27.41.140)
I pulled a self-powered, silicon light meter out of the closet, positioned it above the tube, and it worked perfectly. The resolution for comparison is so good, I can see a marked difference over a ra .......
480: Tubes Asylum, RE: Can I use a different uf coupling cap (0.00)
Posted by Triode_Kingdom on 2022-09-07, 07:21:22 (24.27.41.140)
"What happens if you make R21 a rheostat?" A potentiometer in that position will only make changes to the total AC current. Equal AC current will still flow through both tubes. Bench testing amplifier .......
481: Tube DIY Asylum, RE: Measuring Arbitrary Waveforms (0.00)
Posted by Triode_Kingdom on 2022-09-06, 18:48:20 (24.27.41.140)
Thanks, I need to find an economical way to accomplish this. I don't have a RMS meter, and don't really have much need for one other than this. Good point about common mode, but it won't be an issue i .......
482: Tube DIY Asylum, Measuring Arbitrary Waveforms (0.00)
Posted by Triode_Kingdom on 2022-09-06, 16:08:08 (24.27.41.140)
The waveform below is the output waveform of an ultrasonic filament supply that I modified to operate tubes like the 211 and 845. The fundamental is approximately 85 kHz. Given that it's almost square .......
483: Tubes Asylum, RE: Can I use a different uf coupling cap (0.00)
Posted by Triode_Kingdom on 2022-09-06, 14:47:13 (24.27.41.140)
I know it's not what you asked about, but I really dislike the use of an integrated circuit CCS in these amps. First, it's an IC attached to the signal path. Second, omitting a balance control at the .......
484: Tube DIY Asylum, I measure it if necessary (0.00)
Posted by Triode_Kingdom on 2022-09-06, 14:39:24 (24.27.41.140)
What I mean by this is that I might measure the driver circuit if the final numbers aren't acceptable. I use a 10:1 probe to avoid loading the circuit, and I input that to a sound card measurement sys .......
485: Tubes Asylum, RE: Mystere owners. El34 - 6ca7 advise please (0.00)
Posted by Triode_Kingdom on 2022-09-03, 13:52:36 (24.27.41.140)
I think this describes one of the significant differences between Dynaco's ST-70 and the ST-35. The EL84 is simply one of the world's finest tubes. .......
486: Tubes Asylum, RE: Mystere owners. El34 - 6ca7 advise please (0.00)
Posted by Triode_Kingdom on 2022-09-02, 17:04:02 (24.27.41.140)
A pentode power tube should draw much more screen current over a wider range than a beam power tube. That's one of the problems using the EL34 in pentode mode - providing a stiff screen supply that wo .......
487: Tube DIY Asylum, RE: But the distortion of the voltage amp and driver gets amplified, right? nt (0.00)
Posted by Triode_Kingdom on 2022-09-02, 16:40:55 (24.27.41.140)
"How can distortion not be amplified?" It's the percentage of distortion that isn't amplified. The percentage doesn't change merely because the signal becomes larger (or smaller). What if we send the .......
488: Tube DIY Asylum, RE: But the distortion of the voltage amp and driver gets amplified, right? nt (0.00)
Posted by Triode_Kingdom on 2022-09-01, 13:02:01 (24.27.41.140)
The signal is amplified, not the percentage of distortion. Any additional distortion at the output comes from the power stage itself. In addition, distortion adds as the square root of the sum of the .......
489: Tube DIY Asylum, RE: Output stage distortion always overrides driver characteristics. (0.00)
Posted by Triode_Kingdom on 2022-08-31, 20:45:08 (24.27.41.140)
I assume it's due to the much larger swing required from the power tubes, plus non-linearities in the iron. Percent distortion from a driver pushing a few volts with good headroom should be less than .......
490: Tube DIY Asylum, That's what I said (0.00)
Posted by Triode_Kingdom on 2022-08-31, 08:48:57 (24.27.41.140)
"the final and only important arbiter of sound quality is our ears" "Final" being the key word here. :) .......
491: Tube DIY Asylum, RE: 2nd harmonic (0.00)
Posted by Triode_Kingdom on 2022-08-31, 08:46:15 (24.27.41.140)
"likely because its coming from the single-ended circuitry" I'm sure you're correct, but it's not typical of the amps I design and build. Output stage distortion always overrides driver characteristic .......
492: Tube DIY Asylum, RE: Little Things... (0.00)
Posted by Triode_Kingdom on 2022-08-31, 08:30:44 (24.27.41.140)
Are you testing distortion and response with each of these changes? If you're seeking accuracy and resolution, maintaining good numbers is a prerequisite to testing by ear. .......
493: Vintage Asylum, RE: Magnatone?!? (0.00)
Posted by Triode_Kingdom on 2022-08-29, 18:42:35 (24.27.41.140)
Magnatone is known for its implementation of frequency-shifting vibrato using varistors. They did this at a time when other manufacturers were using the term to describe simple volume modulation. :: .......
494: Tube DIY Asylum, RE: Someone over there take your lunch money? * (0.00)
Posted by Triode_Kingdom on 2022-08-29, 18:30:29 (24.27.41.140)
Let's see, how can I say this kindly? The mods are untenable dictators, and they've created an environment I despise. I begged them to retract my membership, and I won't go near there ever again. :: .......
495: Tube DIY Asylum, RE: Mullard circuit done right I say (0.00)
Posted by Triode_Kingdom on 2022-08-29, 07:02:46 (24.27.41.140)
"done better than right by a cast of dozens at Diyaudio.com" Yes, I can see how it might take quite a few people over there to create an amp that sounds good. .......
496: Tubes Asylum, RE: Not likely to help (0.00)
Posted by Triode_Kingdom on 2022-08-27, 20:23:16 (24.27.41.140)
Cooling the glass does draw heat away from the internal elements. But unless they're running at temps beyond those intended by the manufacturer, it doesn't make a difference. Some glass transmitting t .......
497: Tubes Asylum, Not likely to help (0.00)
Posted by Triode_Kingdom on 2022-08-27, 15:43:05 (24.27.41.140)
The dissipation ratings of output tubes are established in a convection-cooled environment at room temperature. A fan won't help unless the tubes are being pushed above their ratings for some reason. .......
498: Tube DIY Asylum, Citation V Rebuild Complete (0.00)
Posted by Triode_Kingdom on 2022-08-27, 15:39:15 (24.27.41.140)
I'll start this by apologizing for not taking pictures. I had the choice of shooting and editing photos or installing the bottom cover and listening to my "new" amp. I just couldn't wait. I did take t .......
499: Tube DIY Asylum, RE: Magnavox SE84 Amp: Circuit to Pre Amp Outputs? (0.00)
Posted by Triode_Kingdom on 2022-08-27, 14:52:23 (24.27.41.140)
There are lots of discussions about the Magnavox amps online. They definitely have a cult following. You'll need a follower of some type to drive preamp output jacks. If this is for casual listening, .......
500: Tube DIY Asylum, RE: Citation V Progress (0.00)
Posted by Triode_Kingdom on 2022-08-25, 16:41:00 (24.27.41.140)
The turret boards are in good condition, so no need to replace them. I put them back into the amp this afternoon after replacing the back-side jumper wires and cleaning off tons of dirt. Most of the o .......
Found total of 500 records, Query: , Author: Triode_Kingdom in All Forums, Time: 3 sec.