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1: SET Asylum, RE: Audio Note UK Ongaku (0.00)
Posted by Paul Barker on 2023-01-29, 04:18:19 (81.159.194.62)
Wish I hadnt clicked that link, jibberish. Waste of time Ill never get back. .......
2: Tube DIY Asylum, RE: Can choke be used for power voltage regulation ? (0.00)
Posted by Paul Barker on 2022-05-13, 22:05:05 (81.159.196.60)
You're talking about a "swinging choke". In the 1980's they were available in electronics shops for stabilising the mains voltage for such things as enlargers for wet process photograph printing, sinc .......
3: SET Asylum, RE: cost of SET (0.00)
Posted by Paul Barker on 2022-05-09, 00:11:40 (81.159.195.189)
I like my pse 801@ amp. About 10 years ago I liked my push pull 1619 as triode amp, transformer phase splitter right before the output valves, small feedback winding on primary like the quad II OPT's .......
4: Tube DIY Asylum, RE: "Hazen Grid Mod"question (0.00)
Posted by Paul Barker on 2022-05-06, 03:08:42 (81.159.195.172)
when youre wife says 'thought someone was actually playing our piano' is a good moment. .......
5: Tube DIY Asylum, RE: "Hazen Grid Mod"question (0.00)
Posted by Paul Barker on 2022-05-04, 00:15:15 (81.159.195.172)
You learn a lot about yourself when you get a friend to blind test for you. Find someone you are confident in and you'll be surprised how much proud Papa syndrome, vested interest syndrome, and how mu .......
6: Tube DIY Asylum, RE: "Hazen Grid Mod"question (0.00)
Posted by Paul Barker on 2022-05-02, 00:56:28 (109.249.189.177)
Thanks for clearing that up. OP had a remarcable nack of making a completely simple mod confusing. .......
7: Tube DIY Asylum, RE: Thermal runaway? (0.00)
Posted by Paul Barker on 2022-05-01, 03:13:00 (81.159.195.172)
Does the amp have cathode bias? when you get the amp upside down, check the bypass cap for that valve isnt drawing current. Aged 64 here, where did the time go since vsac? Working as a heating enginee .......
8: Tweakers' Asylum, RE: External Trimmer Pots (0.00)
Posted by Paul Barker on 2022-04-29, 01:26:11 (81.159.195.172)
re is an idea from the world of furnaces (central heating boilers to me). Access to adjustments, such as forcing full power and then minimum power for analysis and subsequent as required adjustments o .......
9: Tweakers' Asylum, RE: electrolitics (0.00)
Posted by Paul Barker on 2022-04-29, 01:12:27 (81.159.195.172)
Oh and if Sonicraft has that bad customer service shake off the dust from youre feet. .......
10: Tweakers' Asylum, RE: electrolitics (0.00)
Posted by Paul Barker on 2022-04-29, 01:09:57 (81.159.195.172)
I dont know Sonicraft and it never came up when I hit the link. Also though if at all possible I dont accept cookies. Dont just answer yes. Youre being fed websites related to youre history and youre .......
11: Tube DIY Asylum, RE: Hum balance new idea (0.00)
Posted by Paul Barker on 2022-04-22, 19:23:50 (109.249.189.189)
No, it's out of phase due to the topology. 300b and 845's are common cathode so each stage is out of phase with next stage. A cathode follower is in phase with the next. Regardless of the why's and wh .......
12: Tubes Asylum, RE: Anyone tried the PSVANE WR50 (0.00)
Posted by Paul Barker on 2022-04-22, 00:09:36 (81.159.194.226)
You might get youre resistors, I'd ordered gm70 special silver collet bases before the invasion, lost all hope seeing the tracking always showed them at a Russian port. But they actually arrived here .......
13: Tubes Asylum, RE: Anyone tried the PSVANE WR50 (0.00)
Posted by Paul Barker on 2022-04-17, 06:34:26 (81.159.194.226)
Well going forward were never going to get newly made valves that are well enough made if the makers cant get rewarded for their efforts. There is still time to gather nos valves which are the better .......
14: Tweakers' Asylum, RE: op amp oscillation and oscilliscope (0.00)
Posted by Paul Barker on 2022-04-16, 07:24:36 (81.159.194.226)
True but if it sounds better why fret! If it doesnt sound better go back. .......
15: Tubes Asylum, RE: Anyone tried the PSVANE WR50 (0.00)
Posted by Paul Barker on 2022-04-16, 04:47:05 (81.159.194.226)
This picture from my collection shows it better. .......
16: Tubes Asylum, RE: Anyone tried the PSVANE WR50 (0.00)
Posted by Paul Barker on 2022-04-16, 00:49:07 (81.159.194.226)
Much longer plate than 801a though some 10's have bigger plates than others, mostly theyre about the size of a 45 plate . Filament is indeed TT from the text in youre link. Beatiful to the eye, and lo .......
17: Tubes Asylum, RE: Pardon me, Sir (0.00)
Posted by Paul Barker on 2022-03-28, 00:51:22 (81.159.196.118)
I think if you copy one line and put it in a browser it will pop up. Stephies spread sheet for the 801a was used as one valve into 10k. So double the power and distortion because there are two valve a .......
18: Tubes Asylum, RE: Pardon me, Sir (0.00)
Posted by Paul Barker on 2022-03-28, 00:40:30 (81.159.196.118)
I dont know if this link will work here. https://i.postimg.cc/ncvX0m4L/03900-D5-A-BB35-485-C-BAFD-A8-D495-AAB13-E.png https://i.postimg.cc/59ryx33y/1-B9-D0892-9968-4-E24-98-DC-824-C5-EFBFB3-D.png http .......
19: Tubes Asylum, RE: Pardon me, Sir (0.00)
Posted by Paul Barker on 2022-03-28, 00:24:20 (81.159.196.118)
You missed that I said it's pse? 6 watts per valve. .......
20: Tubes Asylum, RE: 6HV5A vs. D3a (0.00)
Posted by Paul Barker on 2022-03-26, 07:53:28 (81.159.196.118)
I don't have the first tube, but enjoying d3a triode on hammond bifilar interstage driving 801a pse at 10k load for 801a's. 12 watts in class A deliberately avoiding A2 as distortion heads for the sky .......
21: Tube DIY Asylum, RE: Norman Crowhurst feedback article (0.00)
Posted by Paul Barker on 2022-03-25, 02:05:19 (109.249.181.118)
I wasn't born until 1957, I think my first electronics project was a Sinclair ZX81 in 1981. But I had already built an 11ft from scratch sailing dinghy in my single mum's garage by the time I was 16. .......
22: Tube DIY Asylum, RE: Silver Collet GM70 Bases. (0.00)
Posted by Paul Barker on 2022-03-21, 00:09:42 (81.159.196.118)
Thank you .......
23: Tube DIY Asylum, RE: Don't think there is any compound that will (0.00)
Posted by Paul Barker on 2022-03-20, 07:29:00 (81.159.196.118)
Thank you. Seller left some construction glue filler on. I was planning to turn a ring on the laithe (sorry can't imagine correct spelling Apple no help). But when I cut my first base I'll make the c .......
24: Tube DIY Asylum, lets try "direct link" (0.00)
Posted by Paul Barker on 2022-03-20, 02:55:31 (81.159.196.118)
picture I hope! .......
25: Tube DIY Asylum, Still having no luck posting images here in the way it works on less archaic forums nt. (0.00)
Posted by Paul Barker on 2022-03-20, 02:45:39 (81.159.196.118)
Still no luck posting images here .......
26: Tube DIY Asylum, Silver Collet GM70 Bases. (0.00)
Posted by Paul Barker on 2022-03-20, 02:42:00 (81.159.196.118)
I ordered these from Russia before the invasion, and thought theyd never arrive, but to my surprise yesterday they came. I live in England. I hadn't read the ebay advert properly, I must have had blin .......
27: Tube DIY Asylum, RE: Can I build an amp with any of these? (0.00)
Posted by Paul Barker on 2022-03-18, 22:51:47 (81.159.196.118)
It's too steep a learning curve to understand enough to even build an existing circuit and parts costs high. The long answer is to big: I'm really sorry. But class A2 operation is like planning to cli .......
28: Tube DIY Asylum, RE: Can I build an amp with any of these? (0.00)
Posted by Paul Barker on 2022-03-17, 22:40:57 (81.159.196.118)
oddly the 811 data sheet shows higher plate dissipation than the 811a. the only way to use it in audio is positive grid bias so you would need low impedance reasonable power driver direct coupled. No .......
29: Tube DIY Asylum, RE: Can I build an amp with any of these? (0.00)
Posted by Paul Barker on 2022-03-17, 11:50:25 (81.159.196.118)
oddly the 811 data sheet shows higher plate dissipation than the 811a. the only way to use it in audio is positive grid bias so you would need low impedance reasonable power driver direct coupled. No .......
30: Tube DIY Asylum, RE: 2a3 amp (0.00)
Posted by Paul Barker on 2022-03-17, 01:10:07 (81.159.196.118)
Bang on .......
31: Tube DIY Asylum, RE: 2a3 amp (0.00)
Posted by Paul Barker on 2022-03-16, 01:58:34 (81.159.196.118)
Yes Hammond do a 150h @ 8mA plate choke, pretty reasonable, so reasonable you can series two and half the capacitance double the inductance. In plate choke scenario its ideal to put a grid choke in as .......
32: Tubes Asylum, RE: Tube making countries (0.00)
Posted by Paul Barker on 2022-03-05, 01:18:36 (81.159.196.101)
Can I just say a word to the wise. Dont order from Russia ATM, there is a blockade, whether USA still trades with them I dont know. But I ordered two gm70's with silver collet basses which have been i .......
33: Tube DIY Asylum, RE: Can you post the schematics? (0.00)
Posted by Paul Barker on 2022-02-27, 23:44:51 (81.159.196.6)
great spot! .......
34: Tube DIY Asylum, RE: Can you post the schematics? (0.00)
Posted by Paul Barker on 2022-02-27, 23:41:04 (81.159.196.6)
Good spot! meant for Tray somehow it slotted in at wrong level. Honest to God that was not me! .......
35: Tweakers' Asylum, RE: AliExpress (0.00)
Posted by Paul Barker on 2022-02-25, 06:15:34 (81.159.195.66)
I pay hificollective without problems, havent ordered from allied express for many years but had no issues there either. .......
36: Tweakers' Asylum, RE: Safe To Buy From HIFICOLLECTIVE, UK? (0.00)
Posted by Paul Barker on 2022-02-25, 06:02:28 (81.159.195.66)
Bought loads of components from Nick Lucas, no issues whatsoever, recommend him to anyone. .......
37: Tubes Asylum, RE: 211-D Northern Electric from the 20-ties. (0.00)
Posted by Paul Barker on 2022-02-19, 22:55:41 (81.159.194.34)
I have one, same era, oxide filament. Blows Tungsten fillament tubes out the park. I always have a wry smile when the herd are all saying Tungsten filaments sound good. Yes valves with tungsten filame .......
38: Tubes Asylum, RE: 211-D Northern Electric from the 20-ties. (0.00)
Posted by Paul Barker on 2022-02-18, 22:31:46 (81.159.194.35)
I have one, same era, oxide filament. Blows Tungsten fillament tubes out the park. I always have a wry smile when the herd are all saying Tungsten filaments sound good. Yes valves with tungsten filame .......
39: Tube DIY Asylum, RE: Hammond Interstage Transformers (0.00)
Posted by Paul Barker on 2022-02-17, 07:32:08 (81.159.195.204)
yes core size very suitable for 15mA dc plenty of inductance (ive forgotten what I measured but 70h comes to mind) kick ass bass and lovely refined trebble, cant fault them at 15mA, once youve found t .......
40: Tube DIY Asylum, RE: Hammond Interstage Transformers (0.00)
Posted by Paul Barker on 2022-02-17, 07:13:12 (81.159.195.204)
I use the 126 bifilar to connect a triode connected d3a @15mA quiescent to an 801a. Note 15mA is the max current Hammond allow. Ive biased the 801a in A1 not into grid current. Also be aware there is .......
41: Tube DIY Asylum, RE: Can a Voltage Doubler Work Right Off Of Line Voltage? (0.00)
Posted by Paul Barker on 2022-02-17, 06:54:54 (81.159.195.204)
youve already been told the answer. Bang goes the power supply overcurrent protection device. Thats the UK electrical regs name for the distributer box fuse or breaker. I cant speak usa electrical reg .......
42: Tube DIY Asylum, RE: DrLowMu, a suggestion: (0.00)
Posted by Paul Barker on 2022-02-13, 00:21:02 (81.159.196.210)
Welcome back .......
43: SET Asylum, RE: cost of SET (0.00)
Posted by Paul Barker on 2022-02-03, 07:25:09 (109.249.189.242)
The service man is riht, its a principle most businesses would do well to learn. My accountant gave it a name but I forgot the name. This principle belongs in good business, but I cant remember the ac .......
44: SET Asylum, RE: Short Answer (0.00)
Posted by Paul Barker on 2022-02-03, 01:30:21 (81.159.196.210)
Yes I wasnt cuting into the thread at the right place. Not yet able to get my head back in time to when I only had to use my autonomic nervous system to answer a thread. Now that Im fresh in here agai .......
45: Tube DIY Asylum, RE: So you're saying 2 resistors? (0.00)
Posted by Paul Barker on 2022-01-21, 08:25:06 (81.159.196.210)
Sorry can't get post image to behave! Might be the forum rejecting it. Might not! .......
46: Tube DIY Asylum, RE: So you're saying 2 resistors? (0.00)
Posted by Paul Barker on 2022-01-21, 07:12:09 (81.159.196.210)
These days most of not all transformers sold into uk market at rated at 230 v. Most of actual uk voltage is 240. in the good old days there were 2 or 3 primary taps say 5v 10v for instance. So you cou .......
47: Tube DIY Asylum, RE: Agree - "grid resistor" - but then again... (0.00)
Posted by Paul Barker on 2022-01-16, 23:14:30 (81.159.195.118)
The problem is newbies arent about nuances of expression juggling by experts. They see a resistor going directly to the grid so think people are talking about this when they refer to "grid resistor". .......
48: Tube DIY Asylum, RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion (0.00)
Posted by Paul Barker on 2022-01-16, 03:34:33 (81.159.195.118)
Just so OP knows grid "resistor" full name is "grid leak resistor" most common newby mistake is not understanding this and not connect it right so no output. O p definitely needs to swat up on some be .......
49: Tube DIY Asylum, RE: Wow! +100000 (0.00)
Posted by Paul Barker on 2022-01-14, 04:59:11 (81.159.195.118)
Nice .......
50: Tube DIY Asylum, RE: Stephies Power Supply??? (0.00)
Posted by Paul Barker on 2022-01-11, 23:17:53 (81.159.195.118)
Thanks for the feedback. .......
51: Tube DIY Asylum, RE: Stephies Power Supply??? (0.00)
Posted by Paul Barker on 2022-01-10, 22:22:34 (81.159.195.118)
Its an LR power supply, using choke input and class A2 triodes to shunt regulator controlled by a string of vr tubes which run from b+ to grid of class A2 tube. Usually 572b or for lower power consump .......
52: Tube DIY Asylum, RE: How do you like the bass produced by SET but not PP amp (0.00)
Posted by Paul Barker on 2022-01-10, 22:11:10 (81.159.195.118)
For SE to hold a candle to PP bass you have to have very tight power supply. Ive liked Stephie's resistorless capacitorless power supply most of every power supply Ive built for SE amps, and I dont ge .......
53: Tube DIY Asylum, RE: How do you like the bass produced by SET but not PP amp (0.00)
Posted by Paul Barker on 2022-01-10, 00:45:06 (81.159.195.118)
For SE to hold a candle to PP bass you have to have very tight power supply. Ive liked Stephie's resistorless capacitorless power supply most of every power supply Ive built for SE amps, and I dont ge .......
54: SET Asylum, RE: How often do you roll? (0.00)
Posted by Paul Barker on 2022-01-06, 23:43:07 (81.159.195.118)
Yes capacitor rolling, but also circuit modding to lessen the capacitors. Be careful whose advice you take too. People advise caps which can kill youre tubes. Real old paper in oil caps need checking .......
55: Tubes Asylum, RE: Addendum... do those screws mount into the board? (0.00)
Posted by Paul Barker on 2022-01-03, 22:37:12 (81.159.195.118)
Youre only problem is fear of the unknown. An engineer who takes things apart all day of every day, knows more than you has strong hands and fingers just pulls tubes out fearlessly. Things fight you, .......
56: Tube DIY Asylum, RE: I think I hold the record for stupid hum problems (0.00)
Posted by Paul Barker on 2022-01-03, 22:11:30 (81.159.195.118)
I remember the cellphone prrrpppp blu blu blu blerppp. An early V1505 breadboard that near enough filled my dining room and a hum I couldnt trace. Music sounds so much better when everything quiet, no .......
57: Tubes Asylum, RE: A suggestion (0.00)
Posted by Paul Barker on 2021-12-31, 23:12:18 (81.159.195.118)
Its fun to do, I often find my younger self has answered what I had forgotten since. Its real handy! .......
58: Tube DIY Asylum, RE: 300B IT 1:1 845, A2 possible? (0.00)
Posted by Paul Barker on 2021-12-28, 09:18:12 (81.159.195.118)
I know A2 doesn't always sound bad, but the 801a looks bad. I have an 801a amp that I kept to A1 because of those findings, You get a very nice 6.4 watts easily, I am using interstage coupling. Our UK .......
59: SET Asylum, RE: None of those speakers has 97 dB below 100 Hz (0.00)
Posted by Paul Barker on 2021-12-28, 08:48:46 (81.159.195.118)
In the 60's and 70's the charts and stats were printed lies. The man who said to you, when youre faced with a room purposed to sell speakers, "you have to listen to the speakers in youre home was the .......
60: SET Asylum, RE: None of those speakers has 97 dB below 100 Hz (0.00)
Posted by Paul Barker on 2021-12-28, 04:11:49 (81.159.195.118)
In the 60's and 70's the charts and stats were printed lies. The man who said to you, when youre faced with a room purposed to sell speakers, "you have to listen to the speakers in youre home was the .......
61: SET Asylum, RE: A watt is a watt! (0.00)
Posted by Paul Barker on 2021-12-28, 01:29:01 (81.159.195.118)
Like .......
62: Tube DIY Asylum, RE: 300B IT 1:1 845, A2 possible? (0.00)
Posted by Paul Barker on 2021-12-28, 00:57:16 (81.159.195.118)
Im not up to speed with posting images here. In this distortion chart, if you can see it, guess which power level is in A2! I think Im allowed one photo a week. So Ill have to explain rather than s .......
63: Tube DIY Asylum, RE: 300B IT 1:1 845, A2 possible? (0.00)
Posted by Paul Barker on 2021-12-27, 23:49:02 (81.159.195.118)
surely the dc resistance of the transformer takes the A2 portion off the predicted (predicted as if dc resistance didnt exist) characteristic curves. Step down transformer or direct couple. Aside from .......
64: Tube DIY Asylum, RE: Chinese transformers (0.00)
Posted by Paul Barker on 2021-12-24, 00:55:14 (81.159.195.118)
Power supply choke might need small cap to ground each end. True its low inductance, but youre not questioning smoothing youre questioning something tiresome to listen to. get youre sig gen out:put sc .......
65: Tube DIY Asylum, RE: Chinese transformers (0.00)
Posted by Paul Barker on 2021-12-22, 04:51:55 (81.159.195.118)
Power supply choke might need small cap to ground each end. True its low inductance, but youre not questioning smoothing youre questioning something tiresome to listen to. get youre sig gen out:put sc .......
66: SET Asylum, RE: A watt is a watt! (0.00)
Posted by Paul Barker on 2021-12-22, 01:18:56 (81.159.195.118)
I must say its a filip to my state of mind to see so many of the old names still holding up the banner and giving great advise as they always did. Wont name them but really feels like home from home. .......
67: SET Asylum, RE: A watt is a watt! (0.00)
Posted by Paul Barker on 2021-12-22, 01:06:09 (81.159.195.118)
The trials of life friend. .......
68: SET Asylum, RE: A watt is a watt! (0.00)
Posted by Paul Barker on 2021-12-20, 23:48:08 (81.159.195.118)
In London on Tottenham Court Rd in The '70's as a teenager I would druel over the amaising statistics of the amplifiers. Took me many years to realise it was all lies! Some people havent learned that .......
69: SET Asylum, RE: EML 45 / Korneff clone (0.00)
Posted by Paul Barker on 2021-12-20, 23:14:53 (81.159.195.118)
" The only way you'll know is if you try them out in your system..." So true, and always has been, but so often neglected. .......
70: Tube DIY Asylum, RE: Article far from KISS (0.00)
Posted by Paul Barker on 2016-12-26, 08:12:43 (95.150.45.185)
for me kiss would start with the circuid diagram, toomany links later still without a circuit i wrote whole thread here and who le linked page as not at all kiss, so. moved away. .......
71: Tube DIY Asylum, RE: some reading about Sakuma-san (0.00)
Posted by Paul Barker on 2011-09-24, 12:18:25 (2.25.129.115)
I don't expect Romy or anyone else phased Sukuma. .......
72: Tube DIY Asylum, RE: O/T interesting take on Slate (0.00)
Posted by Paul Barker on 2007-10-10, 15:35:03 (80.42.16.75)
Steady on, How can you complain of shilling when that is exactly what Jim has done for you. As for fury Daren is the most calm natured person I have ever known. I always believe in giving credit wher .......
73: Tube DIY Asylum, on the 845 (0.00)
Posted by Paul Barker on 2007-05-12, 22:40:21 (80.42.38.253)
If you remember I never did like it. Have not tried all of the latest offerings but still can't find as good a result as comes sratght away easy with the nos 211. The gevt4c is a great bread and butte .......
74: Tube DIY Asylum, Re: Guys...... (0.00)
Posted by Paul Barker on 2007-05-12, 22:34:11 (80.42.38.253)
Hi Vinney, you are now a very mature contributor with loads of experiencial learning behind you. I really liked your summing up. I have been browsing your 211 questions above. I don't go in for the 6c .......
75: Tube DIY Asylum, Re: Yeah, I know. (0.00)
Posted by Paul Barker on 2007-05-12, 22:20:23 (80.42.38.253)
I wouldn't bother, choke input is vastly superior. What you have produced sounds better to you, why go back? .......
76: Vinyl Asylum, Re: Another confirmation about my plinthing experience this year. (0.00)
Posted by Paul Barker on 2006-12-29, 07:15:33 (88.108.125.112)
Yes I love my 301 in 20mm slate plinth with Mayware arm and denon 103. I would like a 30mm plinth. Enjoy the music review is an independant review not an advertisement. I am best mates with the man be .......
77: Vinyl Asylum, Slatedeck review (0.00)
Posted by Paul Barker on 2006-12-27, 14:46:14 (88.108.125.112)
I've had one of these slate plinths on my 301 for a while now, I did speak about it then, here is a reviewer that seems even more bowled over than I was. I've done looking. .......
78: Tube DIY Asylum, Re: ML4 again... Paul Barker? (0.00)
Posted by Paul Barker on 2006-09-02, 13:30:19 (88.108.14.175)
Steve Shiels of PX4 fame built a fun low wat amp with a close valve, I don't recall the number but a slightly souped up ML4 I think. It sounded good. Personally I haven't had success with the ML4 as a .......
79: Tube DIY Asylum, Re: ML4 again... Paul Barker? (0.00)
Posted by Paul Barker on 2006-08-30, 13:59:20 (88.108.3.120)
It probably was me. I'm not sure I can find the data at the momnent as I'm not as tuned in as I was then. Will let you know as soon as I find something. .......
80: Tube DIY Asylum, TT21 same heater (0.00)
Posted by Paul Barker on 2006-08-28, 23:57:16 (88.108.3.120)
They did catch on for a while but seem to have fallen behind again. It seems not many people like to change their amps slightly. .......
81: Vinyl Asylum, Re: J.D doesn't the Slatedeck Plinths look like mine ? Look (0.00)
Posted by Paul Barker on 2006-08-19, 14:53:50 (88.108.0.157)
Yes if you look at the three tier one you will see that the acuracy of the cutting is very fine, I think it's meant to be acurate to less than 1mm. They have some very fancy equipment and can make exa .......
82: Vinyl Asylum, Re: Garrard pic of the day (0.00)
Posted by Paul Barker on 2006-08-18, 23:41:15 (88.108.0.157)
I expect they will be making a wood box to satisfy that end of the market. Personally I like the open look, and i don't perceive any audio advantages from the wood, just disadvantages. Slate sides wou .......
83: Vinyl Asylum, Re: Looks (0.00)
Posted by Paul Barker on 2006-08-18, 23:39:16 (88.108.0.157)
You are right on the money, tap it while the sound system is on, nothing more than the sound your finger would make on a lump of slate. Tap a wooden plinth and you can hear the colouration or addition .......
84: Vinyl Asylum, Re: Garrard pic of the day (0.00)
Posted by Paul Barker on 2006-08-18, 23:34:19 (88.108.0.157)
Well it is just right, there is no colouration it is transparent, just allows the sound passage. I can't say the timing is any different, but this is a Garrard 301 here, it can slug any atempts to put .......
85: Vinyl Asylum, Re: Garrard pic of the day (0.00)
Posted by Paul Barker on 2006-08-18, 10:52:20 (88.108.0.157)
I have probably the first one off the production line. Garrard 301 Mayware Arm Denon 103 Previously had own cld plinth, puting the Slatedeck was one of those great moments when you are so pleased that .......
86: Tube DIY Asylum, Re: what is the advantage of the ultraparth ? is it better than (0.00)
Posted by Paul Barker on 2006-08-16, 15:34:01 (88.108.15.75)
Sometimes it's better sometimes it isn't. Try it and see if it's better in your scenario. .......
87: Tube DIY Asylum, Re: what is the advantage of the ultraparth ? is it better than (0.00)
Posted by Paul Barker on 2006-08-16, 15:32:49 (88.108.15.75)
Isn't it just (1/mu+1)* bypass cap. .......
88: Tube DIY Asylum, Re: Does anyone here do a design for a fee? (0.00)
Posted by Paul Barker on 2006-08-15, 13:14:55 (88.108.15.75)
I'm struggling with the conflict that you can know what valves and priorities are best, but can't do anything about it yourself. Before I knew how to design my amps I didn't know which valves were bes .......
89: Tube DIY Asylum, Re: Transformer Questions (0.00)
Posted by Paul Barker on 2006-08-04, 23:17:29 (88.108.9.203)
Then again put a variac on the primary and load the secondary, see at what maximum primary voltage it is comfortable (doesn't get too hot to touch and doesn't make too much mechanical noise through ma .......
90: Tube DIY Asylum, Re: Transformer Questions (0.00)
Posted by Paul Barker on 2006-08-04, 23:13:00 (88.108.9.203)
Turns per volt acceptable for 400hz would be dramaticaly too few at 50hz or 60hz. You could calculate back. Turns per volt is determined as N = (E X 10 to pwr 8)/4.44fBA B= flux density A=area of core .......
91: Tube DIY Asylum, Re: of course... (0.00)
Posted by Paul Barker on 2006-08-01, 13:51:03 (88.108.9.203)
Yes I had an oxide 212 but it was d.o.a. Actually quite a proportion of them come d.o.a. it's a frightening business trying to buy these things, and some of them die in use later, which is equally ups .......
92: Tube DIY Asylum, Re: oxide fils (0.00)
Posted by Paul Barker on 2006-07-31, 14:19:02 (88.108.9.203)
STC4211D. STC is the UK leg of Westerb Electric, for evey WE there is an STC prefixed 4. This includes 4300A which a friend of mine had a pair of for a while before the rediculous value placed on them .......
93: Tube DIY Asylum, Re: Tks, Paul. Not sure how to respond. (0.00)
Posted by Paul Barker on 2006-07-30, 14:49:34 (88.108.7.226)
Sukuma stuff is very different to any other way. Might be the only way or might be the other ways are valid. Sorry I don't have any 845 schematics tucked away. If you get round to using those oxide co .......
94: Tube DIY Asylum, Re: Thanks, Jeffrey. That is a good one. Also found "il Monstro" (0.00)
Posted by Paul Barker on 2006-07-30, 01:46:46 (88.108.7.226)
Well it goes like this, you are gambling anyway. You have to build something so do so, then build something else and so on, until you know what's best for you. There is not only one good amplifier sty .......
95: Tube DIY Asylum, Re: AC heaters a concern for a hi-pass amp? (0.00)
Posted by Paul Barker on 2006-07-29, 00:58:06 (88.108.7.226)
The first harmonic 120hs is a very nast sound, selective filtering of 60hz that doesn't address 120hz may sound worse than a correct balance of harmonics. Have you considered the phase effects of chos .......
96: Tube DIY Asylum, Re: AC heaters a concern for a hi-pass amp? (0.00)
Posted by Paul Barker on 2006-07-29, 00:57:06 (88.108.7.226)
The first harmonic 120hs is a very nast sound, selective filtering of 60hz that doesn't address 120hz may sound worse than a correct balance of harmonics. .......
97: Tube DIY Asylum, Re: AC heaters a concern for a hi-pass amp? (0.00)
Posted by Paul Barker on 2006-07-27, 23:18:33 (88.108.14.234)
You would still hear the 100hz (120hz) fundamental and the harmonics of the hum. However it might not be sufficient to bother you with hum bucker. Sometimes ac heating wirks ut ok anyway, sometimes it .......
98: Tube DIY Asylum, Re: I think you are right (0.00)
Posted by Paul Barker on 2006-07-26, 16:04:27 (88.108.14.234)
Oh good you too then. .......
99: Tube DIY Asylum, Re: Now that's interesting. However, the Kite only has evil intent.... (0.00)
Posted by Paul Barker on 2006-07-26, 13:14:13 (88.108.14.234)
I heard they areall vegetarians when people are looking but when our backs are turned they eat poultry. I had an uncle like that, a sworn vegetarian but in the morning most of the cold beef left in th .......
100: Tube DIY Asylum, Re: capacitors in a battery supply (0.00)
Posted by Paul Barker on 2006-07-26, 13:08:24 (88.108.14.234)
Well bateries can sound nasty but I haven't found capacitors fix them. What I have found so far, bateries on cathodes are quie good but not as nice as a resistor. Bipass cap on battery doesn't help. B .......
101: Tube DIY Asylum, Re: where to find nickel-iron alloy sheet metal (tape roll) for very cool.... (0.00)
Posted by Paul Barker on 2006-07-25, 11:48:45 (88.108.14.234)
Actually the phrase isn't appropriate because you mean in a single move, whereas a fell swoop by a Kite is a death blow exerted with visciousness and evil intent. .......
102: Tube DIY Asylum, Re: No, I'm not kidding at all, there are multiple reasons for.... (0.00)
Posted by Paul Barker on 2006-07-22, 09:20:01 (88.108.14.234)
In your PP design you might get away with 6.3v heater versions due to the cancellation of PP. .......
103: Tube DIY Asylum, Re: Got to be very very gentle... (0.00)
Posted by Paul Barker on 2006-07-18, 07:45:12 (88.108.14.234)
IO can't spell jet (you know the ones for burners) obviously. .......
104: Tube DIY Asylum, Re: Got to be very very gentle... (0.00)
Posted by Paul Barker on 2006-07-18, 07:43:27 (88.108.14.234)
I havew an ultrasonic cleaner like dentists use for cleaning get's I did try holding a couple of valves' pins in the water, they seemed to sound better after. Jim you'd be just the man to bring a litt .......
105: Tube DIY Asylum, Re: how to tell when choke core saturated? (0.00)
Posted by Paul Barker on 2006-07-17, 10:05:19 (88.108.14.149)
Yes at the knee when smoothing ability falls off hard. measure voltage out voltage in ratio compare it at different ac voltage swings and current draw to see what use it is to you. Gapping is also imp .......
106: Water Cooler, Re: Dow Jones ( way off topic ) (0.00)
Posted by Paul Barker on 2006-07-14, 12:37:42 (88.108.14.149)
PS if anyone has contacvt with CJ Poulus off the Vinmtage I lost his details (in a hard drive crash) and had already sent him the money for a WE 211 and various other valves. After Vintage closed he v .......
107: Water Cooler, Re: Dow Jones ( way off topic ) (0.00)
Posted by Paul Barker on 2006-07-14, 12:35:38 (88.108.14.149)
Oh dear, when the Dow Jones gets a cold the ftse 100 catches pneumonia. I just wish I'd kept all those Mullard ECC83's instead of sending them to some guy off the Vintage for 50p a pop. .......
108: Tube DIY Asylum, Re: Inductance Theory Questions (0.00)
Posted by Paul Barker on 2006-07-14, 09:39:11 (88.108.14.149)
Maybe it's a swinging choke, or not gapped hardly at all. .......
109: Tube DIY Asylum, Re: Inductance Theory Questions (0.00)
Posted by Paul Barker on 2006-07-14, 00:00:47 (88.108.14.149)
secondly, the inductance is usually fairly constant up to a point where the core begins to saturate from where it tals off. It depends on the gaping philosophy of your supplier whether they start this .......
110: Tube DIY Asylum, Re: all passive amp sound the same? (0.00)
Posted by Paul Barker on 2006-07-03, 23:18:15 (88.108.14.106)
quality of switch, plugs sockets wire routing pot chassis feet all vary sound. .......
111: Tube DIY Asylum, Re: Why not? (0.00)
Posted by Paul Barker on 2006-07-02, 12:19:15 (88.108.14.106)
Yes indeed, and what if the 2a3 draws a little grid current, I bet they can't cope with it without sheding loads of inductance. I don't know which ones these are but I tested some which had half the p .......
112: Tube DIY Asylum, Re: I just went through all of this (0.00)
Posted by Paul Barker on 2006-07-02, 08:46:16 (88.108.14.106)
It's just a 6db per octave roll off. In practice I find it helps, and I believe it is because the cone is not suffering. Using the following formula set f yourself and derive bipass cap Ck = 1/(2pifr_ .......
113: Tube DIY Asylum, Re: all passive amp sound the same? (0.00)
Posted by Paul Barker on 2006-07-02, 08:03:16 (88.108.14.106)
What's a passive amp? If it amplifies how can it be passive? Please explain what you mean and I'll knoiw what to reply to. .......
114: Tube DIY Asylum, Re: I just went through all of this (0.00)
Posted by Paul Barker on 2006-07-02, 08:01:55 (88.108.14.106)
Of course if your Lowther drivers are unaffected by unwanted bass information this won't work for you. That's the key, whether the drivers work better at a more limited range. .......
115: Tube DIY Asylum, Re: I just went through all of this (0.00)
Posted by Paul Barker on 2006-07-02, 08:00:07 (88.108.14.106)
Why not size the cathode resistor bipass cap to roll of bass from 20hz? OR even higher, depending where your horns roll off. That is to say since the horn is only going to go so low (I don't know let' .......
116: Tube DIY Asylum, Re: Hmm, I would not go that high (0.00)
Posted by Paul Barker on 2006-07-02, 07:55:36 (88.108.14.106)
Yes I've seen those bumps on sims, ears tell a different story. .......
117: Tube DIY Asylum, Re: Grid choke and optimum coupling cap value (0.00)
Posted by Paul Barker on 2006-07-02, 03:56:18 (88.108.14.106)
oh and it's 9hz not khz. isn't there an edit feature on this forum? .......
118: Tube DIY Asylum, Re: Grid choke and optimum coupling cap value (0.00)
Posted by Paul Barker on 2006-07-02, 03:54:59 (88.108.14.106)
sorry the 80,435 figure is ohms not hz. .......
119: Tube DIY Asylum, Re: Grid choke and optimum coupling cap value (0.00)
Posted by Paul Barker on 2006-07-02, 03:50:55 (88.108.14.106)
XL at 20hz is 80,435hz so 0.22 coupling cap -3db is 9khz as lonmg as this is your only 6db high pass filter of this value you are OK. Any others become additive and would start to impact on bass. ::: .......
120: Tube DIY Asylum, Re: Serious transformer problem (0.00)
Posted by Paul Barker on 2006-07-01, 00:01:16 (88.108.14.106)
I would be thinking lamination consistency problem, take both apart reassemble on opposite bobbins is same result reversed? .......
121: Tube DIY Asylum, Re: The man without a choke input suply doesn't know what he's talking about anyway. (0.00)
Posted by Paul Barker on 2006-06-25, 12:28:25 (88.108.14.106)
well go get you the right power transformer. .......
122: Tube DIY Asylum, Re: C-core OPT winding question again.... (0.00)
Posted by Paul Barker on 2006-06-25, 08:37:05 (88.108.14.106)
Easiest way to imagine it is to picture a torroid, hold both bobbins in your hand and place them round the core so to speak. Or to put it another way imagine a break in the core, pass each bobbin onto .......
123: Tube DIY Asylum, Re: please forgive my ignorance, but I would like to suggest.... (0.00)
Posted by Paul Barker on 2006-06-25, 02:16:11 (88.108.14.106)
You'll get no raguments from me on that philosophy brother, Just pointing the dood at what he wanted to know, not saying he's going the right way. I spent an enormous effort building a two stage shunt .......
124: Tube DIY Asylum, Re: Did someone say 6a5g..... (0.00)
Posted by Paul Barker on 2006-06-24, 21:05:30 (88.108.14.106)
I couldn't really tell the difference between them and the 6b4g at the time, it was now so long ago I wouldn'y like to be any more specific. I viewed it then as a dht without the hassle. .......
125: Tube DIY Asylum, Re: never give up (0.00)
Posted by Paul Barker on 2006-06-24, 11:42:23 (88.108.14.106)
Ah the namesake 6a5g now there's a valve, I have just one pair. Wish I could lay my hands on r120. For me triode connected pentodes don't do it. .......
126: Tube DIY Asylum, Re: 6em7 (0.00)
Posted by Paul Barker on 2006-06-24, 11:16:24 (88.108.14.106)
since the standard operating pojnt bias is -20v there is no need for a mu of 72 first stage, so no, I use 7193 which is a 6j5 with anode and grid terminals taken out at the top to reduce input capacit .......
127: Tube DIY Asylum, Re: thanks for the fun. explanation please on the 4H? (0.00)
Posted by Paul Barker on 2006-06-24, 10:24:30 (88.108.14.106)
on a common core inductance increases cubically with turns. twice the turns results in four times the inductance. You were probably looking at it from the perspective of two chokes on seperate cores c .......
128: Tube DIY Asylum, Re: One inductor. Two identical windings. Pop quiz. (0.00)
Posted by Paul Barker on 2006-06-24, 07:49:21 (88.108.14.106)
Yes you are absolutely correct, I got that one wrong. Everyone else got the 4h wrong though so I'm not stupid you know. .......
129: Tube DIY Asylum, Re: question on "the output voltage you expect is reasonable for the tube you intend to use" (0.00)
Posted by Paul Barker on 2006-06-24, 07:40:56 (88.108.14.106)
actually the valve doesn't know anything about the outside world so in a series pass valve the voltage drop across the valve is the Anode Voltage, therefore not normaly a restriction. The current it c .......
130: Tube DIY Asylum, Re: what is your goal? (0.00)
Posted by Paul Barker on 2006-06-24, 00:28:31 (88.108.14.106)
Hi Jim, there is a place in every person's home who has efficient enough speakers for a small idht triode amp. There are qualities in idht which do not exist in any dht, and vice versa. It isn't just .......
131: Tube DIY Asylum, Re: One inductor. Two identical windings. Pop quiz. (0.00)
Posted by Paul Barker on 2006-06-24, 00:18:59 (88.108.14.106)
1,4,0,1,0 .......
132: Tube DIY Asylum, Re: C3g as driver for 300b (0.00)
Posted by Paul Barker on 2006-06-19, 14:24:21 (88.108.8.229)
Sorry Mark your splitting hairs. It is well known you get the best from pentodes by looking at the curves on their side, and using low load resistor to keep the loadline away from the knee. That's wha .......
133: Tube DIY Asylum, Re: C3g as driver for 300b (0.00)
Posted by Paul Barker on 2006-06-18, 21:47:27 (88.108.8.229)
Friend of mine very much recomends it as a high transconductance pentode driver. His view is that for pentode drive you get best results from valves of the sort you are talking about. I haven't studie .......
134: Tube DIY Asylum, Re: Does a really good capacitor beat an average interstage transfrormer? (0.00)
Posted by Paul Barker on 2006-06-18, 07:12:10 (88.108.8.229)
I can't say but just wanted to point out that the transformer replaces three components one valves load, one valves grid refernece and dc blocking, so you aren't comparing it to a cap only. You may fi .......
135: Tube DIY Asylum, Re: really basic questions, about shunt regulating a 45 output stage (0.00)
Posted by Paul Barker on 2006-06-18, 00:54:02 (88.108.8.229)
It would work but be poor, as not enough regulator current flow, I think it would be modulated by the music resulting in strange effects at loud volumes. Very difficult to get the vr tube to conduct t .......
136: Tube DIY Asylum, Re: SRPP Loftin-White WITHOUT Cathode Bias (0.00)
Posted by Paul Barker on 2006-06-18, 00:45:47 (88.108.8.229)
You might want to try swapping out 6sl7 for 6072 or if you don't need much gain 6sn7. Adjust circuit values accordingly. What is it the Morrison Micro uses? parallel 5687 was it? Loads of options to i .......
137: Tube DIY Asylum, Re: SRPP Loftin-White WITHOUT Cathode Bias (0.00)
Posted by Paul Barker on 2006-06-18, 00:39:58 (88.108.8.229)
I wouldn't build it. You could full wave rectifiy as centre tapped secondary and take the central node from the centre tap. Something strange about the 4k7 variable resistance in the lower half route .......
138: Tube DIY Asylum, Re: A good C-core OPT winding question (0.00)
Posted by Paul Barker on 2006-06-17, 09:37:40 (88.108.8.229)
Yes. Moreover it is more important to have a full layer of secondary, so you adjust your winding ratio to fit the perfect lay. Turns ratio is not so important, you musn't compromise the even filling o .......
139: Tube DIY Asylum, Re: A good C-core OPT winding question (0.00)
Posted by Paul Barker on 2006-06-14, 10:43:32 (88.108.8.229)
regarding number of layers don't go too mad you get diminishing returns at the extremes the result sounds awful. 5 and 3 on each leg would be more than enough. .......
140: Tube DIY Asylum, Re: A good C-core OPT winding question (0.00)
Posted by Paul Barker on 2006-06-14, 10:41:19 (88.108.8.229)
best way to find out is do a trial, wind 4,000 turns set it up as a choke, gap it for maximum smoothing at the current you want to use, calculate the inductance knowing the ripple reducation and the c .......
141: Tube DIY Asylum, Re: Problem with DC amps is THE capacitor in the signal path... (0.00)
Posted by Paul Barker on 2006-05-31, 15:33:01 (88.108.15.46)
If only it were that direct a link between sound and size of cap. Position is also important. Still I envy your simple mind. .......
142: Tube DIY Asylum, Re: Problem with DC amps is THE capacitor in the signal path... (0.00)
Posted by Paul Barker on 2006-05-28, 15:33:57 (88.108.15.46)
It isn't a bigger sonic problem in a dc amp than in an rc amp. .......
143: Tube DIY Asylum, Re: Problem with DC amps is THE capacitor in the signal path... (0.00)
Posted by Paul Barker on 2006-05-28, 10:41:37 (88.108.15.46)
I don't find the cathode bipass cap to be a problem in dc amps, though I wouldn't dream of using a lytic anywhere. PS I don't consider wkz BG's lytics. I actually find power supply caps in such an amp .......
144: Tube DIY Asylum, Re: Overspec'ing output tubes. Or why are all my vintage EL84s dead? (0.00)
Posted by Paul Barker on 2006-05-27, 08:21:14 (88.108.3.115)
All the old British equipment with Mullards in have blackened el84's. Too small an envelope, well known fact. cool it or burn it. Great sounding valve. .......
145: Tube DIY Asylum, Re: Have you seen the video? Yep! (0.00)
Posted by Paul Barker on 2006-05-19, 23:22:42 (88.108.1.128)
I bought some old phenolic 212 bases some years ago now. The ht on the amp was 1k5. There was a fault somewhere which set up oscilation, I don't know the process by which the oscilation caused it to, .......
146: Tube DIY Asylum, Re: Very high voltage regulator - who, what? (0.00)
Posted by Paul Barker on 2006-05-19, 23:10:29 (88.108.1.128)
You need to find Chimera Labs 211 Sound Practices artile. Also study Steve Benches resistorless capacitor less supply. I based mine on Steve. At the moment it's just 700v shunt current 200mA feeds a l .......
147: Tube DIY Asylum, Re: Paul.....if I may ask. (0.00)
Posted by Paul Barker on 2006-05-16, 12:47:27 (88.108.4.222)
Yes it's a very solid performing combination. Oneo fthe few times doing what you think will work, does work. .......
148: Tube DIY Asylum, Re: Paul.....if I may ask. (0.00)
Posted by Paul Barker on 2006-05-14, 09:36:56 (88.108.4.222)
ps, Nick tried 2a3 but far prefered 45. .......
149: Tube DIY Asylum, Re: Paul.....if I may ask. (0.00)
Posted by Paul Barker on 2006-05-14, 09:35:12 (88.108.4.222)
Hi Peter, Yes I scrapped my 6em7 pp I'm afraid, just a bit of fun. My friend Nick G has made a really solid 211 amp which beats all comers at our meetings. I think in his latest version it is on the l .......
150: Tube DIY Asylum, Re: 211 and 845 tubes (0.00)
Posted by Paul Barker on 2006-05-11, 11:53:53 (88.108.4.22)
Except to say that Peter Qvortrup has some 845's which have an inverted pip. These are supposed to be the best according to him because of the extra support he inverted pip offers to the anode. I have .......
151: Tube DIY Asylum, Re: 211 and 845 tubes (0.00)
Posted by Paul Barker on 2006-05-11, 11:48:04 (88.108.4.22)
211d Western Electric. Not knowledgable about 845's. .......
152: Tube DIY Asylum, Re: Metal plate vs graphite plate (0.00)
Posted by Paul Barker on 2006-04-27, 14:27:39 (88.108.10.180)
Yes agreed, actually after hearing copper I have no heart for the cheaper graphite gm70's. Perhaps if they cost me more i would like them? I believe I am easily deluded subliminally by my own mind. :: .......
153: Tube DIY Asylum, Re: So what -are- your fave 211's/813's? (0.00)
Posted by Paul Barker on 2006-04-27, 14:24:49 (88.108.10.180)
Actually I've only tried three 211 types the most common gevt4c the oxide coated filament WE 211D and the Chinease. No surprises, Chinease is unlistenable, vt4c is best bargain valve today, we211d is .......
154: Tube DIY Asylum, Re: Metal plate vs graphite plate (0.00)
Posted by Paul Barker on 2006-04-27, 00:01:35 (88.108.10.180)
I have discovered one consistent result, country /era of origin affects sound significantly in 813's and 211's. Might well be true of other transmitters. OTOH I have used nos (Taylor) and modern Svetl .......
155: Tube DIY Asylum, Re: Metal plate vs graphite plate (0.00)
Posted by Paul Barker on 2006-04-26, 23:57:44 (88.108.10.180)
Yes I've found with other valves that some sound different to others of the same number, in some cases it is ones with thick plate material that sound different possibly in a better way, and sometimes .......
156: Tube DIY Asylum, Re: This is all I know (0.00)
Posted by Paul Barker on 2006-02-25, 01:01:10 (88.108.8.200)
A friend and I tried some in ab situation with resistors and we couldn't tell the difference but he thinks after a while they do sound better. I use them because I have them, but couldn't hear an ab i .......
157: Tube DIY Asylum, Re: Just the 811a Grid (0.00)
Posted by Paul Barker on 2006-02-13, 12:30:57 (88.108.10.228)
O wow, I've been so busy with other things last few years completely missed this concept. Think I'd better hook one up. .......
158: Tube DIY Asylum, Re: 811a Schematic (0.00)
Posted by Paul Barker on 2006-02-12, 00:35:52 (88.108.14.162)
What's the cathode load for the 6bg6? It doesn't show on the diagram I'm looking at. .......
159: Tube DIY Asylum, Re: follow-up on the cathode follower loading thread (0.00)
Posted by Paul Barker on 2006-01-02, 11:09:11 (88.108.10.34)
Do me a favour save me reading 304 pages to find it, page no.? .......
160: Tube DIY Asylum, Re: Inductor Measurements for Interstage Transformer (0.00)
Posted by Paul Barker on 2005-11-07, 11:35:16 (88.108.14.175)
Sorry I don't understand your method. Measure ac with a variable resistor and a filament transformer. Find XL of choke put variable resistor and choke in series across low voltage winding. Adjust resi .......
161: Tube DIY Asylum, Re: Newbie heatsink question (0.00)
Posted by Paul Barker on 2005-08-05, 11:57:45 (212.139.197.24)
you use a rubber washer mica spacer purpose made for t0220 devices and heatsink paste. Get them from your electronic supplier. .......
162: Tube DIY Asylum, Re: Hopefully, it's not a... (0.00)
Posted by Paul Barker on 2005-08-03, 10:11:34 (212.139.197.24)
An easy thought, but not true in my experience. I don't think many transformer winders if any have discovered anything those boys didn't know. .......
163: Tube DIY Asylum, Re: SE811a drive stage design question (0.00)
Posted by Paul Barker on 2005-08-01, 05:33:21 (212.139.197.24)
You really want to direct couple it, so a choke might just give you the low vlotage lift you need to bias the 811a correctly. Otherwise you have to make a +/- power supply for the driver and adjust it .......
164: Tube DIY Asylum, Re: a very good idea! (0.00)
Posted by Paul Barker on 2005-07-21, 09:35:04 (212.139.197.24)
Me too. Finished amps impede progress. .......
165: Tube DIY Asylum, Re: Yes, I remember... (0.00)
Posted by Paul Barker on 2005-07-18, 22:53:26 (212.139.197.24)
It's a thought, in the Uk for instance a pair of 1kv Halogen bulbs in series would be about right for a pair of px25's biased up to 50v through 14 ohms. You just have to make a good 4amp 52v filament .......
166: Tube DIY Asylum, Re: Yes, I remember... (0.00)
Posted by Paul Barker on 2005-07-18, 04:14:37 (212.139.197.24)
Of course the real problem is restricting your valve choice, and this technique restricts that considerably, as it's much harder to alter values and meet various parameters of other valve choice. Simi .......
167: Tube DIY Asylum, Re: Hot stuff! (0.00)
Posted by Paul Barker on 2005-07-17, 23:29:37 (212.139.197.24)
Yes you obviously have to think about which valves are suitable when planning to use this technique. It wasn't thrown together by accident. .......
168: Tube DIY Asylum, Re: Hot stuff! (0.00)
Posted by Paul Barker on 2005-07-17, 11:13:59 (212.139.197.24)
No I'm using two stages of 112a, so it's 4 112a's total 1 amp, using 12 volt battery and selecting where in the string of 1/2 ohm resistors to tap off for the filament power. Px25 is 4 12v batteries f .......
169: Tube DIY Asylum, Re: Low cathode resistor bias (0.00)
Posted by Paul Barker on 2005-07-17, 07:38:58 (212.139.197.24)
Sounds good. .......
170: Tube DIY Asylum, Re: Low cathode resistor bias (0.00)
Posted by Paul Barker on 2005-07-16, 23:30:27 (212.139.197.24)
I've just built a px25 amp using that method with one resistor shared between four valves VA and driver across both channels, passing their filamnet and cathode current, resulting in a bias resistor o .......
171: Tube DIY Asylum, Re: Anyone Know For Sure? (0.00)
Posted by Paul Barker on 2005-07-10, 13:08:45 (212.139.197.24)
It isn't important, just a properly rated switch noise suppressor for the mains in your country, any local compoonent supplier can specify what's right for you. It is entirely unnecessary to the good .......
172: Tube DIY Asylum, Re: Capacitor discharge (0.00)
Posted by Paul Barker on 2005-07-10, 13:03:10 (212.139.197.24)
Most kits would have bleeder resistors to discharge the power smoothing caps, so after a few minutes the danger is passed. You could put a volt meter across the anode pin of the valve base and ground .......
173: Tube DIY Asylum, Re: interstage transformer (0.00)
Posted by Paul Barker on 2005-06-28, 13:36:24 (212.139.197.24)
No it won't be for radio either, but I may be misinterpreting the text, see if anyone else has any bright ideas. .......
174: Tube DIY Asylum, Re: interstage transformer (0.00)
Posted by Paul Barker on 2005-06-28, 10:36:23 (212.139.197.24)
I don't fully understand it but it might be totally inapropriate for your requirments. It is clearly too small. It might mean XL is 500k at 21khz which means it is less than 4 henry and totally useles .......
175: Tube DIY Asylum, Re: Oh yea...yours is one of those solutions that is indeed 'simple, neat, and wrong'. (0.00)
Posted by Paul Barker on 2005-06-26, 22:41:31 (212.139.197.24)
WKZ Black Gates are made for the job, sound worse bipassed and better un bipassed than any other power supply cap. Steve Bench Resistorless capacitorless power supply sounds about the same as Black Ga .......
176: Tube DIY Asylum, Re: 2A3 ‘Legacy’ very promising (0.00)
Posted by Paul Barker on 2005-06-22, 09:24:38 (212.139.197.24)
I think I know what he means. And yes 2a3 will be struggling with speakers. Why not take one of your 300b's out of your wedding present and try it SE? You might make a SE 300b a regular concubine. ::: .......
177: Tube DIY Asylum, Re: Curious, clearly not a model with liftime warranty...which model so I an avoid? (0.00)
Posted by Paul Barker on 2005-06-18, 14:15:50 (212.139.200.113)
A 112 which I bought new and an 87 which I bought second hand. Bothe originally worked and both became gradually inacurate at voltage measurement (despite new batteries obviously) to totally rediculou .......
178: Tube DIY Asylum, Re: A Fluke because... (0.00)
Posted by Paul Barker on 2005-06-18, 04:50:18 (212.139.200.113)
I would have said they last for ever a few months ago, in fact if you did a search you'll find me saying so on more than one occasion. Since then two seperate flukes have failed outside the warranty a .......
179: Tube DIY Asylum, Re: Jones tube-regulated supply? (0.00)
Posted by Paul Barker on 2005-06-15, 11:38:49 (212.139.197.17)
No but I have used 6as7 series pass device with 12ax7 on grid. No problems whatsoever. I use Steve Benches ideas a lot, you want to study his pages for valve regulated power supply. I built the -r-c p .......
180: Tube DIY Asylum, Re: You should have at most one ground. (0.00)
Posted by Paul Barker on 2005-06-07, 17:11:11 (212.139.197.17)
"You should have at most one ground " lol .......
181: Tube DIY Asylum, Re: On which subject (0.00)
Posted by Paul Barker on 2005-05-30, 00:16:18 (212.139.197.17)
Yes I just tried that last night. There was more rythm, more musical base and also improvements across the bord. So I decided to try a 2.2 uF cap only for the tweeter. Tweeter inverted, no other cross .......
182: Tube DIY Asylum, Re: What's a "potted transformer", please? (0.00)
Posted by Paul Barker on 2005-05-29, 05:34:59 (212.139.197.17)
As Dan says, Also a potted transformer is a lot easier for the scratch builder to mount, and looks a lot more professional. With audio signal transformers heat isn't an issue. The transformer industry .......
183: Tube DIY Asylum, Re: zero v grid bias (0.00)
Posted by Paul Barker on 2005-05-24, 07:17:43 (212.139.196.191)
Yes I realise that in the case of the original post that is so, the problem still remains of the bias mechanism being loaded down with ever increasing grid current even in a negative bias design with .......
184: Tube DIY Asylum, Re: zero v grid bias (0.00)
Posted by Paul Barker on 2005-05-24, 01:13:50 (212.139.196.191)
Yes but it's the way the dc cf fixes the bias that I like, how is your bias supply? .......
185: Tube DIY Asylum, Re: zero v grid bias (0.00)
Posted by Paul Barker on 2005-05-23, 12:34:44 (212.139.196.191)
Positive bias is best achieved with a direct coupled cathode follower using a +/- power supply. It is actually the best way to nail the bias on a grid current tube. .......
186: Tubes Asylum, Re: 572b Characteristic curves please? Thats correct (0.00)
Posted by Paul Barker on 2005-05-19, 16:26:40 (212.139.196.191)
What makes yo think I'm talking about sv variants. I'm talking about 572b's nothing else. .......
187: Tube DIY Asylum, Re: I know some of the technology employed .... (0.00)
Posted by Paul Barker on 2005-05-19, 16:23:50 (212.139.196.191)
The audio grade photoflash caps were made from a paper which is no longer available. They were as good as Cerafines. .......
188: Tubes Asylum, Re: Derivation (0.00)
Posted by Paul Barker on 2005-05-18, 11:07:55 (212.139.196.191)
Wow, thanks a lot Mark, not only am I amaised at your abilities but also I am very pleased because I was expecting 30mA or so, less than 20mA is a doddle. A very big thank you Mark. I hope all is well .......
189: Tubes Asylum, GM100 DATA (0.00)
Posted by Paul Barker on 2005-05-17, 23:48:50 (212.139.196.191)
I have standard characteristic curves and maximum's, but what I need are grid current curves. To be more specific at 1k5 + 20v what current grid pull? .......
190: Tube DIY Asylum, Re: Get rid of Photo flash caps... (0.00)
Posted by Paul Barker on 2005-05-17, 23:46:53 (212.139.196.191)
Yes but read my post not all photoflashes are the same. .......
191: Tube DIY Asylum, Re: Subs for PHOTO FLASH caps? (0.00)
Posted by Paul Barker on 2005-05-17, 22:30:35 (212.139.196.191)
It has been said certain brands of photoflash are like Ceraphines, so maybe you have those certain brands. Get Ceraphines. Black Gates would be better still. .......
192: Tubes Asylum, Received with thanks nt (0.00)
Posted by Paul Barker on 2005-05-16, 05:47:31 (212.139.196.191)
nt .......
193: Tubes Asylum, Re: 572b Characteristic curves please? (0.00)
Posted by Paul Barker on 2005-05-15, 05:55:48 (212.139.196.191)
Know I don't mean the 572_160, I mean the true 572b. Svetlana do have the curves for it, because as well as their audio variant they did make the true 572b. At the moment I am having to use the 811 cu .......
194: Tubes Asylum, 572b Characteristic curves please? (0.00)
Posted by Paul Barker on 2005-05-14, 21:52:27 (212.139.196.191)
Did anyone print them off from the Svetlana site when it was available? I can't get to it any more. .......
195: Tube DIY Asylum, Re: Silicone is it corrosive ?? (0.00)
Posted by Paul Barker on 2005-05-13, 23:12:59 (212.139.196.191)
I remember it being discussed at our radio ham club, one of the guys had used it on an antenna. It gradually ate it's way through the lot. .......
196: Tube DIY Asylum, Re: There is madness in the method (0.00)
Posted by Paul Barker on 2005-05-11, 00:29:22 (212.139.202.34)
PS, my English friends were greatly entertained the morning I sat next to Voltsecond at breakfast and made the mistake of bringing up transformers as a topic of conversation..... .......
197: Tube DIY Asylum, Re: DIY custom toroid output transformer (0.00)
Posted by Paul Barker on 2005-05-11, 00:27:02 (212.139.202.34)
I think you have a very steep learning curve ahead of you, but all credit to you for having a go. I thought it was that simple 6 or 7 years ago, now I still don't know a 1/10th of what is essential kn .......
198: Tube DIY Asylum, Re: DC heating a 6A5G ? (0.00)
Posted by Paul Barker on 2005-05-05, 14:00:12 (212.139.199.67)
My pair are actually indirectly heated, probably all are. If you don't connect to the cathode you won't get no output. I didn't get any more hum than you would expect from any other indirectly heated .......
199: Tube DIY Asylum, Re: agreed... (0.00)
Posted by Paul Barker on 2005-05-02, 04:07:54 (212.139.203.161)
Exactly, and since there is no standard measure applied across the board it's a meaningless figure, as are most transformer manufacturer's statistics. Chosen to suit their marketing needs. I don't thi .......
200: Tube DIY Asylum, Re: I mean replace the 6C4 circuit with a transformer. (0.00)
Posted by Paul Barker on 2005-05-01, 05:32:56 (212.139.203.161)
NO T ransformer V olume C ontrol. .......
201: Tube DIY Asylum, Re: this is the circuit, here. (0.00)
Posted by Paul Barker on 2005-04-27, 13:49:48 (212.139.203.161)
No prizes for guessing what beer you drink! .......
202: Tube DIY Asylum, Re: Any issues with IT's in close proximity to OPT's? (0.00)
Posted by Paul Barker on 2005-04-27, 13:48:23 (212.139.203.161)
Yes there a lot of issues with IT's picking up interference, most certainly you will have to attach long leeds and free and them around until you find a position / orientation which yielkds the least .......
203: Tube DIY Asylum, Re: That must have raised the voltage. (0.00)
Posted by Paul Barker on 2005-04-25, 00:28:00 (212.139.205.211)
220nf shouldn't raise the B+ SIGNIFICANTLY. .......
204: Tube DIY Asylum, Re: Maybe not so straightforward...(long) (0.00)
Posted by Paul Barker on 2005-04-24, 12:49:19 (212.139.205.211)
Interesting you say this because the best sounding 212 has a different colour graphite to the lesser ones (though a lesser 212 is still 10 times better than a mesh plate 300b); it's Jet black as we sa .......
205: Tube DIY Asylum, Sorry it's 220nf (0.00)
Posted by Paul Barker on 2005-04-24, 12:45:16 (212.139.205.211)
nt .......
206: Tube DIY Asylum, Re: Question about Choke Input Power Supplies (0.00)
Posted by Paul Barker on 2005-04-24, 12:44:42 (212.139.205.211)
Firstly all choke input chokes should have a snubber across them, to protect the choke and power transformer. Morgan Jones' simple snubber seems to work in most situations, 22nf shunt cap either side .......
207: Tube DIY Asylum, Re: Graphite versus Copper Plate GM70 (0.00)
Posted by Paul Barker on 2005-04-22, 09:57:08 (212.139.199.194)
Sound quality we may attribute to the platematerial but it doesn't cross over to all valve types. I'll say some strong stuff which will cause offence now. Graphite gm70's are very coarse and crude sou .......
208: Tube DIY Asylum, Re: choke loads and hummmmmmmmmmmm. (0.00)
Posted by Paul Barker on 2005-04-22, 00:29:42 (212.139.199.194)
You should try the triode wired gec kt66 before you make your mind up finally. .......
209: Tube DIY Asylum, Re: Has anybody built SE GK71? (0.00)
Posted by Paul Barker on 2005-04-21, 10:19:53 (212.139.199.194)
Do a search for 813 schematics. .......
210: Tube DIY Asylum, Re: Transformer coupling and fixed bias... (0.00)
Posted by Paul Barker on 2005-04-20, 23:24:34 (212.139.199.194)
Both answers so far are entirely comprehensive, so there isn't any point repeating what's been said. There are a few things to think about though. What output valve is it? How tight is your fixed bias .......
211: Tube DIY Asylum, Re: It's not triode wired (0.00)
Posted by Paul Barker on 2005-04-19, 12:03:14 (212.139.199.194)
Yer, got it. .......
212: Tube DIY Asylum, Re: It's not triode wired (0.00)
Posted by Paul Barker on 2005-04-19, 00:26:52 (212.139.199.194)
Oops, the load is on the cathode isn't it? OK that's pentode operation then. I'd prefer to see a better fixed screen voltage though with a resistive devider or vr. .......
213: Tube DIY Asylum, Re: It's not triode wired (0.00)
Posted by Paul Barker on 2005-04-18, 23:15:24 (212.139.199.194)
OK after a re - look, I see the cap goes to the cathode so that would be pentode operation, but there isn't a very good method of fixing screen grid voltage, I still think it's drawn wrongly. However, .......
214: Tube DIY Asylum, Re: Schematic is probably OK (0.00)
Posted by Paul Barker on 2005-04-18, 15:12:58 (212.139.199.194)
If that is so it's triode wired. .......
215: Tube DIY Asylum, No there's something wrong with that schematic (0.00)
Posted by Paul Barker on 2005-04-18, 11:27:23 (212.139.199.194)
The most obvious explanation of that resistor is that it forms part of a voltage devider for the screen supply. But the diagram is drawn wrongly. The node at the top of that resistor would connect to .......
216: Tube DIY Asylum, Re: My first SET is up and running! (0.00)
Posted by Paul Barker on 2005-04-13, 00:54:31 (212.139.199.194)
Well, I don't find it that bad. In certain situations it gives that combination of voltage gain and power to drive which you just happen to need. MY main beef with it is the rolled off top end as an i .......
217: Tube DIY Asylum, Re: My first SET is up and running! (0.00)
Posted by Paul Barker on 2005-04-12, 14:49:54 (212.139.199.194)
All can say is that looks top quality. I wouldn't change anything. .......
218: SET Asylum, Always? (0.00)
Posted by Paul Barker on 2005-04-10, 15:27:42 (212.139.197.150)
Unbipassed resistor when pratical sounds better than a battery on the cathode, but not better than a battery on the grid. Cathode resistor bipassed with back to back bipolar Black Gates sounds at leas .......
219: Tube DIY Asylum, Re: Cathode Follower Output Impedance (0.00)
Posted by Paul Barker on 2005-04-10, 15:13:51 (212.139.197.150)
Yes I can't say I've experienced this in an output stage but I cvan confirm that in a driver using a resistor in series with the choke arrives you at the correct bias but does soodle squat to the soun .......
220: Tube DIY Asylum, Re: PS stabilization, perhaps? (0.00)
Posted by Paul Barker on 2005-04-10, 14:29:59 (212.139.197.150)
Whereas I don't doubt your hearing or that of your wife's becaue I also find that the strangest changes make big differences to the sound, what I can't accept is that drawing 1mA off the power supply .......
221: Tube DIY Asylum, Re: Sorry long story...Re: These Wonderful Teflons (0.00)
Posted by Paul Barker on 2005-04-10, 01:57:10 (212.139.197.150)
Interesting stuff. I don't tweak things to such an extend any more. I just use a reasonable vinyl source. No my time is occupied with power amps at the moment. No I haven't got the power supply refine .......
222: Tube DIY Asylum, Re: These Wonderful Teflons (0.00)
Posted by Paul Barker on 2005-04-09, 13:52:04 (212.139.197.238)
too thin sounding not enough base in any amp I've heard them in mine or otherwise. .......
223: Tube DIY Asylum, Re: These Wonderful Teflons (0.00)
Posted by Paul Barker on 2005-04-09, 00:41:21 (212.139.197.238)
Just to balance things out, I don't like the sound of Russian teflons. I know at least two other people who are tired of them also. One man's meat.... .......
224: Tube DIY Asylum, Re: Why paralllel 211's? (0.00)
Posted by Paul Barker on 2005-04-08, 12:57:29 (212.139.197.238)
If you can get enough B+ (unlikely) you could parafeed with one 211 loading the other. Actually if the transformers are rated for that current they should be fine, so it isn't a worry. My main conscer .......
225: Tube DIY Asylum, Re: My PSE 211 amplifier design. Reviewers wanted. (0.00)
Posted by Paul Barker on 2005-04-08, 12:50:16 (212.139.197.238)
You can't use 500k grid leak on 211. I think max is 22k for one, you'd have to use 11k, so you now need a much bigger coupling cap and recalculate drive load impedance ratio. There is no point in the .......
226: Tube DIY Asylum, Re: Why paralllel 211's? (0.00)
Posted by Paul Barker on 2005-04-08, 11:31:10 (212.139.197.238)
Shoot me down in flames, especially because there are plenty of examples using such valves to drive the 211, but for my mileage it always sounds a lot better if you drive it with a proper power valve .......
227: Tube DIY Asylum, Re: Why paralllel 211's? (0.00)
Posted by Paul Barker on 2005-04-08, 11:28:11 (212.139.197.238)
Don't forget you're doubling the dc current demands on the OPT. You can get round that by using parafeed. But this is only one of the problems. The greatest obstacle being the intercation of parallel .......
228: Tube DIY Asylum, Re: My PSE 211 amplifier design. Reviewers wanted. (0.00)
Posted by Paul Barker on 2005-04-08, 11:24:33 (212.139.197.238)
If you post the parts values I'll comment more acurately. But without seeing them I can say that there isn't much voltage gain before the 211's and not much likelyhood to drive the miller capacitance .......
229: Tube DIY Asylum, Re: My PSE 211 amplifier design. Reviewers wanted. (0.00)
Posted by Paul Barker on 2005-04-08, 00:45:38 (212.139.202.76)
What do you think you need R1 for? Why didn't you put circuit values in the circuit? People can't go trawling through your excsessively complexed parts list to evaluate an ill conceived amateur effort .......
230: Tube DIY Asylum, Re: Nope. (0.00)
Posted by Paul Barker on 2005-04-06, 10:45:52 (212.139.202.76)
Brilliant, another person who alters things until they sound best to him. It's the only true way to develop. .......
231: Tube DIY Asylum, Re: what does it meant?? Re: Is choke before rectification (0.00)
Posted by Paul Barker on 2005-04-05, 13:01:41 (212.139.202.76)
Though you may get better sound from smaller first cap, it isn't what I'm talking about. Choke input scenario is where the choke is sufficiently designed and sized so as to satisfy critical inductance .......
232: Tube DIY Asylum, Re: Is choke before rectification better than after? What are the ... (0.00)
Posted by Paul Barker on 2005-04-05, 03:01:08 (212.139.202.76)
Rule of thumb, with pure choke input you get 0.9 times rms voltage less diode drop and dc resistance of choke drop. Best use a small snubber cap at the very least of 220nf or so before the choke, many .......
233: Tube DIY Asylum, Re: Moving my web site (0.00)
Posted by Paul Barker on 2005-04-04, 03:16:00 (212.139.204.146)
Hi Pete I was interested in your pentode stage for the 813 se amp so have ordered a few. Only one small thing occurs to me, you show the distortion more like the triode. Maybe that's not an advantage .......
234: Tube DIY Asylum, Re: Huge power supply caps........? (0.00)
Posted by Paul Barker on 2005-04-03, 00:51:16 (212.139.198.134)
You'll also read in the archives low c hi l power supplies sound best. Now you need to try both aproaches for yourself. There is less science, less discussion, and more experimentation needed to achie .......
235: Tube DIY Asylum, Re: I was listening to the 833A ....... (0.00)
Posted by Paul Barker on 2005-03-30, 05:40:46 (212.139.200.10)
Oh well the poor bugger will have top us the gm100 with it's spherical anode won't he? .......
236: Tube DIY Asylum, Re: Big SET amp project underway (0.00)
Posted by Paul Barker on 2005-03-29, 12:57:38 (212.139.203.31)
Ah theyve copied a goodun. .......
237: Tube DIY Asylum, Re: Big SET amp project underway (0.00)
Posted by Paul Barker on 2005-03-29, 10:42:20 (212.139.203.31)
Lovely! Which brand is that looks like Mullard. Envious of your pin connectors. Love the box, to hell with all those clever arty types who can make stuff look nice. Which continent are you? Can you br .......
238: SET Asylum, Re: Explain my post further (0.00)
Posted by Paul Barker on 2005-03-29, 10:39:15 (212.139.203.31)
It does very much depend on the signal level as Thorsten said. You will notice that the bunching of grid lines takes place towards the extremes. Look at the curve ratio left to right for the signal le .......
239: SET Asylum, Re: KT88 vs 300B in SET mode (0.00)
Posted by Paul Barker on 2005-03-29, 10:35:35 (212.139.203.31)
I've used 6afg extensively because it sounded good so I didn't need to swap it for a 6a3, which would have required more attention to detail in the heating. It sounded good enough is all I can say. Do .......
240: SET Asylum, Re: KT88 vs 300B in SET mode (0.00)
Posted by Paul Barker on 2005-03-28, 11:36:01 (212.139.203.31)
For an introduction to grid curves and loadlines go to this old post of mine. http://db.audioasylum.com/cgi/m.mpl?forum=tubediy&n=28592&highlight=load+lines+Paul+Barker&r=&session= The only thing to a .......
241: SET Asylum, Re:There must be other places where we can be nurse maided. (0.00)
Posted by Paul Barker on 2005-03-28, 11:22:25 (212.139.203.31)
OK there are points on both sides and it's true that we should be good to newbies. Thorsten and I haven't met so I don't know him, and yes he does come over a little abrasive sometimes, but in this in .......
242: SET Asylum, Re:What about a *human* mode, Mr. Thorsten (and the "Mr." is an overstatement) (0.00)
Posted by Paul Barker on 2005-03-28, 06:31:21 (212.139.203.31)
Thirsten was just being factual. That matters more than anything when applied in writing on a technical forum to a question posed technically. Thorsten nailed it, learn from the reply. If a reply apea .......
243: Tube DIY Asylum, Calling Fatbottle (0.00)
Posted by Paul Barker on 2005-03-26, 11:40:38 (212.139.202.221)
I've lost your email address can you email me v1505guy(at)yahoo.co.uk Thanks Paul .......
244: Tube DIY Asylum, Re: 813 load? (0.00)
Posted by Paul Barker on 2005-03-24, 00:22:00 (212.139.199.68)
You'd have been ok in Scarborough UK all year round, we have a cooling sea breeze that comes from Greenland or some cold place like that. My 212 amp serves to suplement the under sized radiator in the .......
245: Tube DIY Asylum, Re: 813 load? (0.00)
Posted by Paul Barker on 2005-03-23, 13:55:08 (212.139.199.68)
I don't use them. I tried them in parafeed SE, and really loved them, but we don't keep everything we've hooked up on a piece of wood do we? .......
246: Tube DIY Asylum, Re: 813 load? (0.00)
Posted by Paul Barker on 2005-03-22, 11:05:55 (212.139.199.68)
They are forceful sounding, loads of grunt / authority, a little Coarse. Very nice for audio. .......
247: Tube DIY Asylum, Re: 813 load? (0.00)
Posted by Paul Barker on 2005-03-22, 10:55:27 (212.139.199.119)
Actually 800v is OK for 813. Might sound better at 2k5 than people expect. Well worth having fun with now. .......
248: Tube DIY Asylum, Re: James 6157 (0.00)
Posted by Paul Barker on 2005-03-19, 14:35:47 (212.139.205.173)
No, but it's not that exact a science. .......
249: Tube DIY Asylum, Re: James 6123HS and 211 (0.00)
Posted by Paul Barker on 2005-03-19, 12:10:25 (212.139.198.132)
I'm using 6157hs on 212. Very good. Listening right now at 1500v HT. Have also used it at 2kv. Not noticed any problems. I try to limit dc current to 130ma Sound is good indeed. Paul .......
250: Tube DIY Asylum, Re: Choke snubber circuit (0.00)
Posted by Paul Barker on 2005-03-19, 06:21:04 (212.139.205.154)
Choke input supplies sound so much better though. .......
251: Tube DIY Asylum, Re: adapting simple RC design to us ITs (0.00)
Posted by Paul Barker on 2005-03-18, 00:21:42 (212.139.205.5)
Here here .......
252: Tube DIY Asylum, Re: Cancel that, I don't have the 10s. Any suggestions? (0.00)
Posted by Paul Barker on 2005-03-18, 00:03:19 (212.139.205.5)
I'd recommend 6c45pi it coupled to 45 or 2a3. You can use the Jeremy Epstein Free Lunch operating point for the 6c45pi. I recommend the Sowter 9525 bifilar IT in this design. I have proved it an excel .......
253: Tube DIY Asylum, Re: 211 filament 10v max and min please (0.00)
Posted by Paul Barker on 2005-03-17, 23:53:12 (212.139.205.5)
Morgan Jones was telling me once how critical it is to keep TT filaments as acurate as possible. I don't recall exactly why, something to do with being on a knife edge between melt down and cathode po .......
254: Tube DIY Asylum, Re: opinions on this 805 SET schema requested (0.00)
Posted by Paul Barker on 2005-03-16, 14:50:38 (212.139.199.160)
I would take out the cathode bias on the 805, if necessary turn down the HT also. Instead of the suggested drivers use the 211 as cathode follower. Share same HT as the output stage, and let the dc im .......
255: Tube DIY Asylum, Re: Building a 211 SET, need schematic. (0.00)
Posted by Paul Barker on 2005-03-12, 10:56:04 (212.139.198.199)
Got the point yet? Wrong valve. Hint there are bigger ones, but dig deep in your pocket. .......
256: Tube DIY Asylum, Re: e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-11, 12:45:11 (212.139.198.69)
Yes, and thanks for the thought, I didn't want you to think I was knocking you or anything, I don't mind people thinking I'm a novice there is nothing to prove. That's why I'm quite happy to share suc .......
257: Tube DIY Asylum, Re: e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-10, 23:35:40 (212.139.198.236)
Thanks for that, you may not be aware of me, I've been quiet for a couple of years, but I realised that one. .......
258: Tube DIY Asylum, Re: e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-09, 09:13:51 (212.139.200.254)
Thanks Alex, it looks like where I've been going wrong is not going through the 8v on grid 1 route and then applying cathode bias. For some reason it seems to matter. I supose could try a 9v battery a .......
259: Tube DIY Asylum, Re: e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-09, 00:29:09 (212.139.207.52)
Well all those manufacturers can't be wrong and little old me right. Must be that inadvertently I've shafted these or they were already shafted. Id still like to hear from someone with empirical evide .......
260: Tube DIY Asylum, Re: e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-08, 22:52:51 (212.139.207.52)
NO it just states A=G2 I connected G3 to cathode. I could try your suggestion but this is so far off I'm befudled. It's not like I threw them into the wrong operating point, I brought them up on a var .......
261: Tube DIY Asylum, Re: e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-08, 22:40:22 (212.139.207.52)
It should be in cut off acording to the published curves, but are they a misprint? Has anyone got actual data? .......
262: Tube DIY Asylum, Re: e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-08, 14:05:01 (212.139.207.14)
Thanks, I have 5 or 6 Mullards, but I haven't tried pairing them up yet since the first two I tried, which are fairly similar are a million miles off the curves. Being the sort of guy that likes to re .......
263: Tube DIY Asylum, e280f triode operating point? (0.00)
Posted by Paul Barker on 2005-03-08, 13:03:05 (212.139.201.111)
I can't make sense of the triode urves for e280f. My Mullards are so far from the curves it's impossible that these curves can be right. For instance at 110v -8.9v I get 66mA. As the curves are worthl .......
264: Tube DIY Asylum, Calling RayP re Yorkshire meeting (0.00)
Posted by Paul Barker on 2005-03-07, 09:37:53 (212.139.206.20)
can you email me again ray I've lost our mails can't remember when you come to Witby need to get a day organised. Thanks Paul .......
265: Tube DIY Asylum, Re: Yorkshire meeting? (0.00)
Posted by Paul Barker on 2005-03-01, 15:34:49 (80.45.200.249)
OK that'll be good. .......
266: Tube DIY Asylum, Re: witch burning (0.00)
Posted by Paul Barker on 2005-02-27, 14:23:36 (80.45.200.101)
email me v1505guy(Insert at symbol)yahoo.co.uk, don't want the spam bots to pick it up. I'm very near Whitby. .......
267: Tube DIY Asylum, Re: Yorkshire meeting? (0.00)
Posted by Paul Barker on 2005-02-27, 08:59:23 (80.45.244.68)
Get a cheap train fair in advance (Apex) and just bring yourself, some vinyl and anything else you can carry. I'll try and find a venu you can reach on a short train trip. Maybe some local enthusiasts .......
268: Tube DIY Asylum, Yorkshire meeting? (0.00)
Posted by Paul Barker on 2005-02-27, 06:47:46 (80.45.194.16)
Any interest in a boat anchor style get together in Yorkshire UK this Summer? I could bring Ariel speakers variable power supply up to 2kv. My own 212 amp. Vinyl front end, but could someone bring a g .......
269: Tube DIY Asylum, Re: Why DC and DRD 2 stage SE amps sound bad) (0.00)
Posted by Paul Barker on 2005-02-20, 14:13:43 (80.45.200.52)
They sound great to me, and a lot better than amps with coupling caps. I usually use either Black Gates or oil caps for the cathode bipass. I don't have such an amp running at the moment, but those I' .......
270: Tube DIY Asylum, Re: Ok you caught my eye!!! What's your favorites??? (0.00)
Posted by Paul Barker on 2005-01-23, 12:34:24 (80.45.207.188)
I haven't had a go at the more recent better Chinease 845's, and no nos. The original Chinease weren't really good enough for me, far prefer nos 211's. 211's are however a little thin compared to the .......
271: Tube DIY Asylum, Re: High Voltage 813? (0.00)
Posted by Paul Barker on 2005-01-22, 11:09:30 (80.45.214.16)
No, but I have tried the 212 at 2kv. It gets ever so slightly lifted by the extra voltage, but it's almost indistinguishable from 1k5v. The 2kv op point has the advantage of not requiring any A2 opera .......
272: Tube DIY Asylum, Re: Which 300B ? ........... A: a 2A3 or a 45 (0.00)
Posted by Paul Barker on 2005-01-22, 11:03:58 (80.45.214.16)
Most people who know what they are talking about don't bother with the 300b. It's not a bad valve, but it's not special either. .......
273: Vinyl Asylum, Re: sme 3009 small weight (0.00)
Posted by Paul Barker on 2004-12-29, 15:10:19 (80.43.120.46)
Oh, please excuse me, clearly I know so little about weights and measures, it made me jump to conclusions. That further information is double helpful, thanjks for taking the time and trouble and putin .......
274: Vinyl Asylum, Re: sme 3009 small weight (0.00)
Posted by Paul Barker on 2004-12-29, 14:44:56 (80.43.120.46)
Oops, 0.8 oz is very little, you must mean the hanging one, I was asking about the one that is directly mounted on a cantilever with graduation scales on the right hand side of the arm as you look at .......
275: Vinyl Asylum, Re: sme 3009 small weight (0.00)
Posted by Paul Barker on 2004-12-29, 14:42:40 (80.43.120.46)
Many thanks for that. .......
276: Vinyl Asylum, sme 3009 small weight (0.00)
Posted by Paul Barker on 2004-12-29, 11:39:41 (80.43.120.46)
Can someone that owns an early 3009 please tell me what the small wiegth which fits on the side weighs and rough dimensions. I need to make one. Thanks Paul .......
277: Tube DIY Asylum, Re: 212E (0.00)
Posted by Paul Barker on 2004-10-26, 12:51:26 (80.46.239.52)
OH I forgot to say congrats that the ebay seller is crediting you. The last duffer I was sold the same seller listed another almost straight away. I emailed him suggesting we swap. NO REPLY! ::: TOPIC .......
278: Tube DIY Asylum, Re: 212E (0.00)
Posted by Paul Barker on 2004-10-26, 12:47:46 (80.46.239.52)
Hi Gerd, At least 1/3rd of my 212's I've bought are completely dead or half alive like your one. I have 2 maybe 3 in that condition and quite a few px4's that have gone that way. In the event they mak .......
279: Tube DIY Asylum, Re: I don't think the 211 will work as well. (0.00)
Posted by Paul Barker on 2004-10-23, 10:17:35 (80.45.167.8)
Thanks Mark, so how do you apply the bias of 35v? Is for instance auto bias possible in grounded grid, and if so does it have to be bipassed as in common cathode? Thanks in advance, Paul. .......
280: Tube DIY Asylum, Re: arc welding sockets (0.00)
Posted by Paul Barker on 2004-10-23, 10:10:27 (80.45.167.8)
Anode clips? Hadn't thought of that. Yes capacitor clamp sounds good. My bases seem to be made of a black plastic looking material. I think they are current production Chinease. Supplier replaced the .......
281: Tube DIY Asylum, Re: Sheer jealousy prevents me answering this question. (0.00)
Posted by Paul Barker on 2004-10-23, 02:30:20 (80.46.234.29)
Yes, practically speaking, I haven't yet brought the rest of the components up to the limits of the 212. It's not really fair to talk about the valve and how it sounds when the rest of the system is g .......
282: Tube DIY Asylum, Re: driver for 212e (0.00)
Posted by Paul Barker on 2004-10-22, 16:34:22 (80.46.235.64)
I haven't got it right myself yet. I was thinking px25 via 2:1 interstage and am awaiting Tribute iron for same, ready for Christmas I am told. Meanwhile I've tried 6em7 dc cf: nice but really stretch .......
283: OTL Asylum, diy otl (0.00)
Posted by Paul Barker on 2004-10-18, 01:03:42 (80.43.119.91)
Will anyone here have knowledge of diy issues? I once breadborded the first Rosenblit from Glass Audio/ Tube Audio Design, which I very much liked, but was side tracked into bigger and "better?" se wi .......
284: Tube DIY Asylum, I'm using Mozilla (0.00)
Posted by Paul Barker on 2004-07-18, 02:02:24 (80.46.236.5)
instead of IE, in many respects it is much better than IE, but it has a few gremlins, one is that it decides whatever heading I previously used I wanted to use again. Another anoyance is that on these .......
285: Tube DIY Asylum, Sorry about the wrong heading (0.00)
Posted by Paul Barker on 2004-07-18, 01:58:04 (80.46.236.5)
Can I just say what a hit your lighting transformers are. They have liberated my building, and I don't hear any negatives. .......
286: Tube DIY Asylum, N-set AR300A Pics (0.00)
Posted by Paul Barker on 2004-07-18, 01:57:17 (80.46.236.5)
Can I just say what a hit your lighting transformers are. They have liberated my building, and I don't hear any negatives. .......
287: Tubes Asylum, N-set AR300A Pics (0.00)
Posted by Paul Barker on 2004-07-01, 00:50:16 (80.45.161.161)
OK I'll do that and as you are on GM70 forum I'll continue over there. .......
288: Tubes Asylum, N-set AR300A Pics (0.00)
Posted by Paul Barker on 2004-06-29, 12:16:52 (80.43.116.90)
Yes Chris and I sometimes get together. I'll be waitning with baited breath for the result also. Do you go to the GM70 Yahoo group? Probably the best place to put up the review. .......
289: Tubes Asylum, N-set AR300A Pics (0.00)
Posted by Paul Barker on 2004-06-29, 08:56:06 (80.43.116.90)
2nd from the left. It is quite different to the other one (with the dirty pins). Only Crittle's has the inverted glass pip for support. On the other one Anode is set at a different hight and braced di .......
290: Tubes Asylum, N-set AR300A Pics (0.00)
Posted by Paul Barker on 2004-06-27, 08:12:20 (80.46.236.52)
http://www.audioasylum.com/audio/tubes/messages/144769.html .......
291: Tubes Asylum, Re: 4212D (0.00)
Posted by Paul Barker on 2004-06-27, 08:09:51 (80.46.236.52)
When I got them out to photograph for you I realise my error, my AR300's are Canadian not Australian. The memory plays tricks with us. What my neighbours don't appreciate is my garden is a natural mea .......
292: Tube DIY Asylum, Re: 4212D (0.00)
Posted by Paul Barker on 2004-06-26, 08:27:18 (80.46.232.152)
Yes, though I have no idea which types I have tried, what I did try was far superior to sn7 or J5 types. Much more brassy, much more to my taste. You can't go wrong with 5/76 .......
293: Tubes Asylum, Re: 4212D (0.00)
Posted by Paul Barker on 2004-06-26, 01:54:43 (80.46.232.152)
Oh shucks I'll have to get one out of the box and have a look. Yes you're right, these are 4212E. The rest that I have are 4212H and V1505 which has an identical structure to my 4212H's but a larger g .......
294: Tubes Asylum, Re: good info to know! (0.00)
Posted by Paul Barker on 2004-06-24, 08:05:19 (80.46.233.178)
Yes that's the order. The AR300 is the favourite but as an equivalent it goes about the process in a completely different way. It doesn't look anything like the various 4212's. The metal plate version .......
295: Tubes Asylum, Erata (0.00)
Posted by Paul Barker on 2004-06-24, 00:34:40 (80.43.116.48)
Reads confusing. It is the metal plate 212 which has shortcomings not the Australian Graphite plate, which is audio Nirvana. Considering the price of 212's this information may not be much practical u .......
296: Tubes Asylum, Metal Plates (0.00)
Posted by Paul Barker on 2004-06-24, 00:32:15 (80.43.116.48)
I know that Dave Slagle likes Copper GM70's, but I have metal plate 212's and various graphite plate versions/equivalents. The metal plate comes second to one particular graphite version (AR300) by a .......
297: Tube DIY Asylum, Re: could you be a little more descriptive? (nt) (0.00)
Posted by Paul Barker on 2004-06-11, 07:42:58 (80.46.235.241)
I don't get involved in arguments. I've made my point, you've made yours. That's the end of it for me. .......
298: Tube DIY Asylum, I don't agree with you nt (0.00)
Posted by Paul Barker on 2004-06-11, 01:58:25 (80.46.235.241)
.......
299: Tube DIY Asylum, You have to look at it differently (0.00)
Posted by Paul Barker on 2004-06-10, 10:22:02 (80.46.238.46)
You don't have curves for the new tube you have created, so you can't draw a meaningful loadline. What you have to do is draw your loadline for 24k, as long as this looks right then you should be happ .......
300: K&K Audio / Lundahl Transformers, Thanks (0.00)
Posted by Paul Barker on 2004-06-08, 00:43:21 (80.43.112.141)
nt .......
301: K&K Audio / Lundahl Transformers, Re: Try This (0.00)
Posted by Paul Barker on 2004-06-07, 10:25:42 (80.45.166.177)
How does this affect output impedance? For instance with an 80 ohme resistor is it increased by (mu +1)*80 in series with internal impedance and dc resistance of OPT? .......
302: Tube DIY Asylum, Re: What is the difference in making a choke input to cap input choke? Thanks ..nt (0.00)
Posted by Paul Barker on 2004-06-06, 05:09:12 (80.43.118.201)
Wow I hadn't seen that Voltsecond discourse before. I sat with Volts one breakfast at vsac. My head is still spinning. Mortals don't need this level of knowledge (though it's nice to know someone unde .......
303: Tube DIY Asylum, Re: For Triode Kingdon re halogen lighting "transformers" (0.00)
Posted by Paul Barker on 2004-06-06, 01:01:30 (80.43.118.201)
You do need to add smoothing after the incoming bridge. I haven't completed my own experients so far because of other demands on my time. For the UK market products (230v nominal 50hz mains) I say nom .......
304: Tube DIY Asylum, Re: 866 or 3B28? opinions solicited (0.00)
Posted by Paul Barker on 2004-06-05, 13:00:25 (80.43.119.150)
Ah you've probably got the same ones I had. .......
305: Tube DIY Asylum, Re: 866 or 3B28? opinions solicited (0.00)
Posted by Paul Barker on 2004-06-05, 08:56:01 (80.43.119.150)
I get you. I made the assumption because I have some solid state diodes on a 3kv transformer which are jumbo four pin base and top cap. .......
306: Tube DIY Asylum, Re: 866 or 3B28? opinions solicited (0.00)
Posted by Paul Barker on 2004-06-04, 22:35:46 (80.45.166.27)
I take it from the four spare bases that the solid state diodes were arranged in a bridge. Use two of those and two valve rectifiers, for which you only require one heater supply in the hybrid arrange .......
307: Tube DIY Asylum, Re: My First DIY Amp! Its Alive! (0.00)
Posted by Paul Barker on 2004-06-04, 09:58:33 (80.46.239.68)
Very good choice for a first amp I'm sure. Can you afford another one the same so you can go stereo? .......
308: Tube DIY Asylum, Performance Measurements Link (0.00)
Posted by Paul Barker on 2004-05-28, 12:01:15 (80.43.113.197)
http://www.pacifier.com/~gpimm/ccs_performance.htm .......
309: Tube DIY Asylum, Re: Now available in UK (0.00)
Posted by Paul Barker on 2004-05-28, 00:54:21 (80.46.232.39)
I haven't used them, but goinbg from the data sheet http://www.ixys.com/98704.pdf In place of your anode load resistor, place the A terminal to the High Voltage, place a current set resistor between t .......
310: Tube DIY Asylum, Re: Now available in UK (0.00)
Posted by Paul Barker on 2004-05-27, 11:24:23 (80.43.119.112)
Yes I got the catalogue, it's the worst catalogue I've seen in my life. I shall have to resort to their web pages. I'm not in any great need at the moment but if one of us gets it together we should d .......
311: Tube DIY Asylum, Now available in UK (0.00)
Posted by Paul Barker on 2004-05-27, 09:07:36 (80.43.119.112)
http://uk.digikey.com/scripts/DkSearch/dksus.dll?KeywordSearch 95 pence each. I haven'r ordered any myself so I don't know what the minimum order value or shipping comes to. If you get round to orderi .......
312: Tube DIY Asylum, Re: 6EM7 Parafeed Headphone (0.00)
Posted by Paul Barker on 2004-05-26, 12:53:20 (80.46.232.174)
Oh that's better. Yes it's worth comparing to see what you like. It's a while since I did it now, but I mostly remember the diode flattened the soundstage a little compared to the battery. Best of all .......
313: Tube DIY Asylum, Re: 6EM7 Parafeed Headphone (0.00)
Posted by Paul Barker on 2004-05-26, 01:45:48 (80.43.118.230)
Curious to know why you used a 10nf coupling cap with a -3db base roll off at 48hz? I prefer nicad cathode bias to diodes but ymmmv. .......
314: Tube DIY Asylum, Re: 6EM7 Parafeed Headphone (0.00)
Posted by Paul Barker on 2004-05-26, 01:44:46 (80.43.118.230)
Curious to know why you used a 10nf coupling cap with a -3db base roll off at 48hz? I prefer nicad cathode bias to diodes but ymmmv. .......
315: Tube DIY Asylum, Re: Yes but either it is in forward conduction mode the whole time (0.00)
Posted by Paul Barker on 2004-05-24, 10:31:58 (80.45.166.66)
I don't believe this subject has mileage after we found that there was no effect. Somebody pinch me, I'll wake up in a minute. .......
316: Tube DIY Asylum, Re: Output power of Gary K's 6EM7 amp? (0.00)
Posted by Paul Barker on 2004-05-22, 08:33:09 (80.45.162.224)
OK curiosity got the better of me. 2.5k = 1.38 watts ((215 - 57)(. 88 - .018))/8 .......
317: Tube DIY Asylum, Re: Output power of Gary K's 6EM7 amp? (0.00)
Posted by Paul Barker on 2004-05-22, 08:25:24 (80.45.162.224)
I've just graphed it out out of interest. I couldn't work with the originator's operating points as they don't match the curves. Instead I used the specified operating point of 150v -20v 50mA. Into 5k .......
318: Tube DIY Asylum, Re: Quick Question about Component Destruction. . . In this case - Power Resistors! (0.00)
Posted by Paul Barker on 2004-05-21, 12:47:05 (80.46.235.156)
Aluminium clad go off like a party popper and fire fine wire across the room if that helps. Leave a good margine of safety and where appropriate a good heatsink. .......
319: Tube DIY Asylum, Re: Oddly enough, I have a ham license. (0.00)
Posted by Paul Barker on 2004-05-20, 23:50:49 (80.43.114.78)
I have a ts-530sp and a Yaesu FT840 plus some 2m and 70cms stuff for local use. We don't get the red neck stuff in Europe but we get lot's of what we call gardening programs. The Voice of Russia alway .......
320: Tube DIY Asylum, Re: Harmonic lower sideband? (0.00)
Posted by Paul Barker on 2004-05-20, 05:14:55 (80.45.160.170)
Yes I was puzzled by the use of the term sideband in this context, since a sideband is something invented by radio amateurs, the carrier frequency is amplitude modulated by the audio but in a differen .......
321: Tube DIY Asylum, You just beat me to it (0.00)
Posted by Paul Barker on 2004-05-19, 11:24:13 (80.45.164.169)
I have a test rig for gapping output transformers and chokes. No change between a diode and a wire link. .......
322: Tube DIY Asylum, Re: Output and INterstage Transformer Winding (0.00)
Posted by Paul Barker on 2004-05-18, 23:46:47 (80.43.119.178)
You can only reduce tyhe number of turns either by using higher B core material, larger core or less turns. Life is full of compromises. .......
323: Tube DIY Asylum, Re: Output and INterstage Transformer Winding (0.00)
Posted by Paul Barker on 2004-05-18, 13:32:39 (80.46.237.123)
I don't expect capacitance to be your problem, more likely leakage inductance, for which you must take the opposite approach and carry on with your base/number of turns line. Yes capacitance comes in .......
324: Tube DIY Asylum, Re: Output and INterstage Transformer Winding (0.00)
Posted by Paul Barker on 2004-05-17, 23:36:25 (80.43.117.85)
That's odd, it should perform better, many kit amps and cheap amps have less than that i.e. 3 and 2, and they easily achieve 20khz bandwidth. Probably emphasising base too much, try gap, turns number, .......
325: Tube DIY Asylum, Re: Output and INterstage Transformer Winding (0.00)
Posted by Paul Barker on 2004-05-17, 11:29:04 (80.46.238.178)
It doesn't help if we don't know what interleaving you have done. If interleaving is satisfactory look at reducing number of turns and gap more optimally. To gap, run a power supply into a load drawin .......
326: Tube DIY Asylum, 40 watts was barely enough (0.00)
Posted by Paul Barker on 2004-04-30, 06:23:31 (80.45.163.250)
For your ml speakers, I can't imagine on reflection a class A1 push pull 300b amp would be powerfull enough. Possibly a Rosenblit OTL? .......
327: Tube DIY Asylum, Re: Amp for Cello (0.00)
Posted by Paul Barker on 2004-04-30, 06:21:51 (80.45.163.250)
I think he's still digging for iron ore to fulfill my order. .......
328: Tube DIY Asylum, Re: Amp for Cello (0.00)
Posted by Paul Barker on 2004-04-30, 00:42:55 (80.45.163.250)
Best Cello sound I heard was on Vry's bare ESL Panel with a single ended dht of quite large proportions which you can't yet get in to. So why do I say it? There was something about the esl which gave .......
329: Tube DIY Asylum, Errata ML6 not 6L4 (0.00)
Posted by Paul Barker on 2004-04-24, 05:20:55 (80.41.30.118)
.......
330: Tube DIY Asylum, Re: Amplification factor of 10 or higher and Rp of 4K-6K Suggestions (0.00)
Posted by Paul Barker on 2004-04-24, 01:09:36 (80.41.29.101)
ML4 or 6L4 which is more readily available. Though it is an output valve it sounds great down at 15mA 100v with 2 nicad cells on the cathode. .......
331: Tube DIY Asylum, Re: My bad... wrong B+... Other comments too... (0.00)
Posted by Paul Barker on 2004-04-21, 11:40:10 (80.41.15.2)
That's more the sort of story I would expect from a good 6em7 amp. .......
332: Tube DIY Asylum, Re: Other Chinese DHTs: 805 and 813 (0.00)
Posted by Paul Barker on 2004-04-21, 11:37:28 (80.41.15.2)
If you mean $43.95 for Chinease 813 I'd much prefer NOS at a similar price. 805 is another matter, they tend to be more expensive nos, though goodness knows why. .......
333: Tube DIY Asylum, Re: Is this SETdistortion, PS noise or what??? 6em7 amp... (0.00)
Posted by Paul Barker on 2004-04-20, 01:16:54 (80.41.8.2)
6EM7 trade mark is crystal clarity and delicacy. Something is wrong or else speakers are too inefficient. .......
334: Tube DIY Asylum, Re: How do I wire a Pentode? (0.00)
Posted by Paul Barker on 2004-04-15, 03:47:43 (80.41.88.224)
No experience of this particular pentode, but usual thing is to use a lowish value load resistor for linearity (view pentode curves in a completely different light to triode curves). Effectively the o .......
335: Tube DIY Asylum, Re: NiMH batteries -- charged? (0.00)
Posted by Paul Barker on 2004-04-13, 13:47:09 (80.41.87.71)
Just check the voltage before you use them, whilst in use them they get a trickle charge, so as long as they are roughly up to voltage in the first place it doesn't matter to what capacity they are ch .......
336: Tube DIY Asylum, Re: What do you mean "other tonuges"... is that USA ?? (0.00)
Posted by Paul Barker on 2004-04-13, 03:57:53 (80.41.0.202)
I'm English, was referring to Far East where the demand always has been for valuable vintage valve gear. Yes I am aware of the problem getting stuff from USA. You need to make friends with someone tha .......
337: Tube DIY Asylum, Re: interesting (0.00)
Posted by Paul Barker on 2004-04-12, 10:51:28 (80.41.40.199)
Hmm, see what you mean. .......
338: Tube DIY Asylum, Re: With the weeker $ (0.00)
Posted by Paul Barker on 2004-04-12, 10:48:25 (80.41.40.199)
I've heard about this but noone has asked me to falsify value, including those people in Taiwan that are falling head over heals to get British Vintage stock.. Is it really that common? You only have .......
339: Tube DIY Asylum, Re: interesting (0.00)
Posted by Paul Barker on 2004-04-12, 01:47:40 (80.41.40.199)
In pure differential amps the signal doesn't pass over the cathode to ground route at all, it circulates around both valves instead. .......
340: Tube DIY Asylum, Re: Ebay Knuckleheads... (0.00)
Posted by Paul Barker on 2004-04-12, 01:44:51 (80.41.40.199)
I couldn't agree more. I do sometimes encounter problems when selling however, always based around people not reading the text, but unless one opens up sales to the world one sees a very poor profit. .......
341: Tube DIY Asylum, Re: Ripple cancellation (0.00)
Posted by Paul Barker on 2004-04-09, 04:30:16 (80.41.67.187)
With your hum balance pot you can completely balance out the difference of potentials across your heater transformer legs. Snip from Steve Bench (the Daddy of ac hum cancellation) "Physically, the fil .......
342: Tube DIY Asylum, Re: LW risky? Not if you use proper protection!!! (0.00)
Posted by Paul Barker on 2004-04-09, 03:13:29 (80.41.67.187)
You missed the point. If the bulb blows the ac resistance becomes infinate but the dc route remains patent, through which the extra current is pulled, nothing is protected from a break in the ac route .......
343: Tube DIY Asylum, Re: LW risky? Not if you use proper protection!!! (0.00)
Posted by Paul Barker on 2004-04-09, 00:55:20 (80.41.67.187)
A very good idea, but the light bulb would only offer protection on the cathode resistor (or when fixed bias deployed direct from cathode to ground). The cathode capacitor has nothing to do with the q .......
344: Tube DIY Asylum, Re: (KYW): Resonant choke with CLCLC? (0.00)
Posted by Paul Barker on 2004-04-09, 00:50:42 (80.41.67.187)
I have used the resonant choke but in the position of second choke after a conventional choke input choke and before a third conventional choke. It is true that overall the supply is made more smooth .......
345: Tube DIY Asylum, Re: Thanks, other comments vs SE (0.00)
Posted by Paul Barker on 2004-03-24, 11:45:02 (212.139.2.70)
I doubt there is any audible 2nd harmonic distortion at 20 watts from a 75 watt amp. .......
346: Tube DIY Asylum, Re: Amity 2003-style, first monoblock more than OK (0.00)
Posted by Paul Barker on 2004-03-23, 09:47:41 (212.139.2.70)
Great. I look forward to hearing it in a month or so when I come to collect my Ariels, and I'll bring the 212 SE so we can compare. .......
347: Tubes Asylum, Re: Ec Data (0.00)
Posted by Paul Barker on 2004-03-21, 14:38:47 (212.139.4.244)
Thanks .......
348: Tubes Asylum, Ec and M7 Data Request. (0.00)
Posted by Paul Barker on 2004-03-21, 09:17:07 (212.139.8.147)
I have some Data for Ec but need basing/pinout and heater voltage. I have less data on the M7. .......
349: Tube DIY Asylum, Re: Triode strapped pentodes (0.00)
Posted by Paul Barker on 2004-03-10, 12:58:54 (80.43.134.150)
Been there, done that , worn the t shirt. 813 Sounded better using the true plate, but it was worth a try.. . .......
350: Tube DIY Asylum, Also (0.00)
Posted by Paul Barker on 2004-03-05, 08:49:32 (80.43.131.207)
Available on VT52 website .......
351: Tube DIY Asylum, Re: Room Temperaure Vulcanisation. (0.00)
Posted by Paul Barker on 2004-03-04, 00:02:27 (80.43.128.201)
Right! We just call it silicon sealer. It has so many applications like holds fish tanks together, baths to walls, prevents washing machine parts leaking, so now another use. The ones I use smell of a .......
352: Tube DIY Asylum, Re: Where is Lynn Olson's site? (nt) (0.00)
Posted by Paul Barker on 2004-03-03, 23:58:48 (80.43.128.201)
http://www.nutshellhifi.com/ .......
353: Tube DIY Asylum, Re: Drowning Capacitors in Hot Glue so as to Isolate them mechanically. . . (0.00)
Posted by Paul Barker on 2004-03-03, 14:44:38 (80.43.129.2)
What is RTV? .......
354: Tube DIY Asylum, Re: Tube/OPT impedance matching: PX25 and 300B (0.00)
Posted by Paul Barker on 2004-03-03, 14:41:04 (80.43.129.2)
I shall be all ears. .......
355: Tube DIY Asylum, Re: Do I need to buy the new 3rd edition? (0.00)
Posted by Paul Barker on 2004-03-03, 13:06:45 (80.43.129.2)
I bought the 3rd and I have the 2nd. Yes there is enough reason to buy the third in my view, I am glad I own both. I might have a completely different approach to Morgan doesn't mean I don't value his .......
356: Tube DIY Asylum, Re: Tube/OPT impedance matching: PX25 and 300B (0.00)
Posted by Paul Barker on 2004-03-03, 13:00:15 (80.43.129.2)
Which px25's do you have or plan to get? After hearing ballons I haven't got the stomach for shoulder px25's. I haven't tried the ones Brian Cherry supplies though I do plan to order them. For all I k .......
357: Tube DIY Asylum, Re: OK!, OK! (0.00)
Posted by Paul Barker on 2004-03-03, 12:50:25 (80.43.129.2)
You likely shall understand it after a few reads because Morgan has a very easy style yet he covers in a progressively unfolding fashion many phono stage issues. I think he'll be very glad of the extr .......
358: Tube DIY Asylum, Re: audioXpress: 2E24 SE Amp cathode follower question (0.00)
Posted by Paul Barker on 2004-03-03, 02:09:53 (80.43.134.149)
The driver requirements depend upon the input capacitance of the next stage, the lowest frequency at which you wish the amp to remain linear, and the peak voltage swing required to drive the output va .......
359: Tube DIY Asylum, Re: Yeah, maybe...., (0.00)
Posted by Paul Barker on 2004-03-03, 00:43:54 (80.43.134.149)
Don't you go back long enough to remember how we used to do it with monodes? .......
360: Tube DIY Asylum, Re: AC HUM IN 833? DOES IT MAKE SENSE? (0.00)
Posted by Paul Barker on 2004-02-26, 14:55:46 (217.137.168.52)
What would make no sense is if he didn't have hum. He's got to employ some coping startegies to deal with the obvious hum problem. Simplest of which is to ensure sufficient hum remains in the HT suppl .......
361: Tube DIY Asylum, Re: Big DH multigrids (0.00)
Posted by Paul Barker on 2004-02-20, 12:30:42 (62.252.224.9)
He didn't show it to me, perhaps he didn't have it at that time. What did he do sell the classic cars to make room for it? .......
362: Tube DIY Asylum, Re: Thanks Mark (0.00)
Posted by Paul Barker on 2004-02-19, 00:19:47 (217.137.138.22)
Not coated but impregnated with Thorium (Thoriated Tungsten) which has it's own problems, namely that it runs out on the surface. It can be flashed and then slow cooked to force more Thorium to the su .......
363: Tube DIY Asylum, Re: Reliability of new Chinese Valve Art 845s? (0.00)
Posted by Paul Barker on 2004-02-18, 05:28:35 (217.137.168.12)
Referring to the old ones, a know someone who matches them for a very large wholesale dealer (not naming names so don't ask). He has a devil of a job finding two that match, they are all over the plac .......
364: Tube DIY Asylum, Re: odd sound from 6SN7's (0.00)
Posted by Paul Barker on 2004-02-11, 01:21:25 (217.137.132.100)
I was reachig for something off my shelf not realising I was disturbing a length of trunking that I had stored there, the other end of which tipped a plastic storage box with 3 212's in, two remained .......
365: Tube DIY Asylum, Re: Help, my GM70s sound harsh (0.00)
Posted by Paul Barker on 2004-02-10, 00:55:27 (217.137.138.27)
Doug did say he changed transformers I think we can credit him with that one. .......
366: Tube DIY Asylum, Re: Transformer Configuration Sanity Check (0.00)
Posted by Paul Barker on 2004-02-09, 10:10:34 (217.137.138.56)
Yes yes and that seems stupid, always conventional to reduce fractions to lowest common denominator. Transformer winders should be sufficient at maths to know that. .......
367: Tube DIY Asylum, Re: Help, my GM70s sound harsh (0.00)
Posted by Paul Barker on 2004-02-09, 10:06:43 (217.137.138.56)
That reminds me I heard the DH 845 at vsac and was also very impressed. I asked Kara if the GM70 was better or worse "it's different" came the reply. Shame they didn't bring it into the show and tell .......
368: Tube DIY Asylum, Re: Help, my GM70s sound harsh (0.00)
Posted by Paul Barker on 2004-02-09, 04:07:58 (62.252.224.9)
Thanks for your honesty Doug. I'm less inclined to blame other parameters, I hope I'm wrong as I have double figures GM70's, but what the heck, let's have the truth. .......
369: Tube DIY Asylum, Re: My Pet Peeve (rant) of the Design Industry (0.00)
Posted by Paul Barker on 2004-02-04, 00:53:22 (217.137.138.26)
My pet rant is power amp designs which clearly don't have sufficient sensitivity. I call sufficient sensitivity something that you can play a Leak Troughline Tuner through. .......
370: Tube DIY Asylum, Re: Novice: use a .0056 cap for a .056? (0.00)
Posted by Paul Barker on 2004-01-31, 01:38:48 (217.137.132.103)
Do you mean wil 0.056 work? Yes. Do you mean will 0.0056 work? No. .......
371: Tube DIY Asylum, Re: Unbelievable (0.00)
Posted by Paul Barker on 2004-01-29, 14:03:16 (217.137.138.13)
I might have been longer than an hour overall, shames me to say it. Just shows how tough valves are. Try doing that with a mosfet! .......
372: Tube DIY Asylum, Re: How are the taps attatched to the main winding? (0.00)
Posted by Paul Barker on 2004-01-29, 14:01:18 (217.137.138.13)
I don't know if they still do so but MAplin in UK once sold a transformer kit where they had wound the primary for you and you made your own secondary. They supplied the lams for self assembly. ::: TO .......
373: Tube DIY Asylum, Re: Unbelievable (0.00)
Posted by Paul Barker on 2004-01-28, 13:30:10 (217.137.168.48)
I cooked some 212's a lovely translucent orange colour with too many anode volts when my AVO was playing up. They loved it, and sound all the btter for it. Burns off the impurities don't you know. I d .......
374: Tube DIY Asylum, Re: Why not a flexible "real" amp? (0.00)
Posted by Paul Barker on 2004-01-27, 12:06:59 (217.137.138.42)
I use a 2,820 VCT transformer off a 3kva variac rectified with U19's choke input with a 35 henry chokeand just a few very large in size very small in capacitance paper in oil caps for all my creations .......
375: Tube DIY Asylum, Re: Why not a flexible "real" amp? (0.00)
Posted by Paul Barker on 2004-01-27, 11:53:13 (217.137.138.42)
Dave .......
376: Tube DIY Asylum, Re: Why not a flexible "real" amp? (0.00)
Posted by Paul Barker on 2004-01-27, 07:50:32 (217.137.138.54)
The answer there is Output transformer Plates as in Arm plates for turntables. .......
377: Tube DIY Asylum, Re: Why not a flexible "real" amp? (0.00)
Posted by Paul Barker on 2004-01-27, 05:53:45 (217.137.132.11)
We need a new category at the next vsac! .......
378: Tube DIY Asylum, Re: No cathode bypass cap. What will happen? (0.00)
Posted by Paul Barker on 2004-01-26, 07:55:03 (217.137.168.63)
Raises internal impedance by 8k, consequently no longer is the primary L of the interstage transformer sufficient for good base. Likely benefits, removal of sibilance associated with poor bipass cap. .......
379: Tube DIY Asylum, erata (0.00)
Posted by Paul Barker on 2004-01-25, 01:21:47 (217.137.138.20)
"there are so many differences so large that I'm struggling to find comparators for you." There are so few differences of this magnitude that we come across in self build audio that I am struggling to .......
380: Tube DIY Asylum, Re: Standard Chinese 845 vs Valve Art 845 (0.00)
Posted by Paul Barker on 2004-01-25, 01:17:16 (217.137.138.20)
I would have expected a more stark result. When comparing Chinease 211 (same crap construction as non valve art 845) to GE VT4C (beautiful construction) the sound difference is night and day. How can .......
381: Tube DIY Asylum, Yes you can nt (0.00)
Posted by Paul Barker on 2004-01-24, 11:35:49 (217.137.132.91)
.......
382: Tube DIY Asylum, Re: Is 845 definietly better than 211 (sonically) ? (0.00)
Posted by Paul Barker on 2004-01-22, 10:20:08 (217.137.132.85)
I agree, only last night a chap called Len who is building an Ongaku clone rang me to talk about the curves of 211. I sadi don't worry about curves, you've heard it haven't you? did you like it? "yes, .......
383: Tube DIY Asylum, Re: Is 845 definietly better than 211 (sonically) ? (0.00)
Posted by Paul Barker on 2004-01-22, 10:20:08 (217.137.132.85)
I agree, only last night a chap called Len who is building an Ongaku clone rang me to talk about the curves of 211. I sadi don't worry about curves, you've heard it haven't you? did you like it? "yes, .......
384: Tube DIY Asylum, Re: Hang on !!!!! (0.00)
Posted by Paul Barker on 2004-01-14, 11:32:12 (217.137.138.48)
I heard about a woman who liked valve audio once but she turned out to be a gender change. Does that count? Probably a virgin though. .......
385: Tube DIY Asylum, Re: IF 300b's SUCK, what triodes do YOU like ?? (0.00)
Posted by Paul Barker on 2004-01-13, 08:38:52 (62.252.224.9)
6EM7 .......
386: Tube DIY Asylum, Re: Hang on !!!!! (0.00)
Posted by Paul Barker on 2004-01-13, 08:37:33 (62.252.224.9)
15 foot of lamp flex (cotton outer, rubber inner) coated in a special metaphisical sound enhancing dope (well actually just modellers dope repackaged but prayed over by a virgin who likes valve audio .......
387: Tube DIY Asylum, Re: Where's the spirit of Gizmo ? (0.00)
Posted by Paul Barker on 2004-01-13, 00:52:34 (217.137.138.8)
All that happens is people stop giving their valid experiences and all you have left are the opinions of textbook junkies. .......
388: Tube DIY Asylum, Re: I`ll explain :-) (0.00)
Posted by Paul Barker on 2004-01-13, 00:50:31 (217.137.138.8)
300b's suck if you don't mind my saying so in my humble opinion not the opinion of anyone else relayed by me, not said to incite argument but to offer my personal listening experience of most types of .......
389: Tube DIY Asylum, Re: Could someone defifine what an "Output Choke" is please? (NT) (0.00)
Posted by Paul Barker on 2004-01-12, 03:44:36 (217.137.132.35)
Not sure what the application you are suing is but for instance you can load an output stage with a choke and couple it to speakers with a cap. You can driectly drive electrostatics with a push pull c .......
390: Tube DIY Asylum, Re: LD1084V calculation question.... (0.00)
Posted by Paul Barker on 2004-01-12, 00:54:28 (217.137.138.26)
Variables which cause shift from expected outcome are: current set by R1 if you don't use 120 ohm Temperature, which is related to 3rd work you are asking of it. Use the formula to best guess then twe .......
391: Tube DIY Asylum, Re: LD1084V calculation question.... (0.00)
Posted by Paul Barker on 2004-01-12, 00:49:47 (217.137.138.26)
Vref is usually 1.25v Set R1 to run near enough 10mA across Vref, so as they suggest use 120 ohm (R1 goes between adj and out) 6.3 = 1.25(1+(R2/120)) 5.04 = 1 + (R2/120) 4.04 = R2/120 R2 = 484.8 ohms .......
392: Tube DIY Asylum, Re: Sorry (0.00)
Posted by Paul Barker on 2004-01-11, 11:09:43 (62.252.224.9)
Well I wouldn't blatantly say it to upset, I was just saying it to illustrate a point. Neither does it mean it isn't sometimes the best option for some people in the UK. It's poor relative to what can .......
393: Tube DIY Asylum, Re: Sorry (0.00)
Posted by Paul Barker on 2004-01-11, 05:59:56 (217.137.168.63)
I beg to differ, I think the Border Patrol 300b is far superior to the wad pse 2a3. As a company I like WAD and I am very friendly with plenty of people who have built their gear, plus I built the pho .......
394: Tube DIY Asylum, Re: eh? (0.00)
Posted by Paul Barker on 2004-01-11, 05:50:37 (217.137.168.63)
Please, I'm no better than 90% of the rest of us and the other 10% could catch up in 6 months. I'm with you regarding pleased that at least one OEM has the same love of choke input power supplies. I o .......
395: Tube DIY Asylum, Re: Choke size - Border Patrol external PSU? (0.00)
Posted by Paul Barker on 2004-01-11, 01:56:52 (217.137.168.9)
Yes agreed I take my hat off to them for being the main oem building amps to our standards or nearly so. .......
396: Tube DIY Asylum, Re: Choke size - Border Patrol external PSU? (0.00)
Posted by Paul Barker on 2004-01-10, 12:58:15 (62.252.224.9)
Don't know but I had a Border Patrol 300b in my house the other day when someone came for a listening session. I didn't comment on the BP amp because I didn't want to upset the guy. I would think a di .......
397: Tube DIY Asylum, Re: SET (0.00)
Posted by Paul Barker on 2004-01-10, 09:06:55 (62.252.224.9)
Break it up into two parts. 1/ it is single ended 2/ it involves using a triode Single ended means one active device working alone powers an output stage be that a radio frequency (RF) amplifier or au .......
398: Tube DIY Asylum, Re: Valve Resistors? Anyone with knowledge of them? (0.00)
Posted by Paul Barker on 2004-01-08, 08:55:56 (217.137.132.41)
Yes they have two filaments inside, presumably for parallel connection/ individual connection or series for three values. I don't expect they take much wattage but could be used as cathode resistor of .......
399: Tube DIY Asylum, Re: They were called "Ballast Tubes". (nt) (0.00)
Posted by Paul Barker on 2004-01-08, 06:55:00 (217.137.168.4)
In USA no doubt they were, and a can of lager is a tinney in Aus, but in UK a thermionic valve is known as a valve.. .......
400: Tube DIY Asylum, Valve Resistors? Anyone with knowledge of them? (0.00)
Posted by Paul Barker on 2004-01-08, 01:27:57 (217.137.132.34)
I bought some ITT L102/2k valve resistors off ebay Item # 2214462305 I have no experience of these. Any one know about them? Paul .......
401: Tube DIY Asylum, Oops sorry Volts nt (0.00)
Posted by Paul Barker on 2004-01-06, 13:17:25 (217.137.168.152)
.......
402: Tube DIY Asylum, Re: Distortion in mid-line output transformers (0.00)
Posted by Paul Barker on 2004-01-06, 08:02:10 (217.137.150.76)
Many ways to introduce distortion via an output transformer. Base distorts at high power due to the phase shift causing eliptical (none linear) load. Paul Joppa has a paper on an example 211 SE transf .......
403: Tube DIY Asylum, Re: Is there a site that I can learn to read Schematics? (0.00)
Posted by Paul Barker on 2004-01-04, 00:35:50 (217.137.132.24)
Just link us the schematic and list all the bits that make no sense at all including such questions as what is a choke what does it do which way round does this capacitor go how do I know what power r .......
404: Tube DIY Asylum, Thanks nt (0.00)
Posted by Paul Barker on 2004-01-03, 08:34:14 (217.137.168.154)
.......
405: Tube DIY Asylum, Re: Old scopes (0.00)
Posted by Paul Barker on 2004-01-02, 23:21:38 (217.137.132.34)
Whatever you do don't chuck away any of the control knobs, I have a guy that fixes these for me, but he can't obtain cosmetic stuff very easily in UK, and often USA stockists run out of selector knobs .......
406: Tube DIY Asylum, AKA 5A/185k nt (0.00)
Posted by Paul Barker on 2003-12-26, 12:56:23 (217.137.168.64)
.......
407: Tube DIY Asylum, Re: But it will change under load (0.00)
Posted by Paul Barker on 2003-12-26, 03:41:06 (217.137.132.96)
Well HK must have known what they were doing, clearly I don't, but I get bye. .......
408: Tube DIY Asylum, Re: TJ PX25 Anyone experienced it? (0.00)
Posted by Paul Barker on 2003-12-26, 03:38:29 (217.137.132.96)
It is rather anoying when forums around the world like this and Ebay convert the GBP symbol to a small r. An L would be more appropriate. I recon it's a conspiracy to kill of the GBP and send us forev .......
409: Tube DIY Asylum, Re: TJ PX25 Anyone experienced it? (0.00)
Posted by Paul Barker on 2003-12-26, 03:35:50 (217.137.132.96)
Talking to Brian Cherry at VSAC he said they were true performers. I whish I'd brought a pair back with me, but it looks like I'll be ordering a pair soon. I have 4 bang on nos shoulder shape and one .......
410: Tube DIY Asylum, Re: But it will change under load (0.00)
Posted by Paul Barker on 2003-12-25, 02:20:00 (217.137.138.10)
Now you are baffling me. I know that the dc resistance of the primary is taken into account when determining the primary inductance in that it is in series with the valve, so is additive to output imp .......
411: Tube DIY Asylum, Re: How high can I push the rated voltage of a cap? (0.00)
Posted by Paul Barker on 2003-12-25, 02:10:37 (217.137.138.10)
I agree to the limitations and have also seen the effect of over voltage on 'lytics, have even caused pio's to dump that oily stuff all over my polished copper chassis. Usually a warning sign of reduc .......
412: Tube DIY Asylum, Re: TJ PX25 Anyone experienced it? (0.00)
Posted by Paul Barker on 2003-12-24, 01:08:58 (217.137.138.22)
By all accounts I've now heard that the market seems quite happy with the ux4 base, and the tooling for the original base would require an order for 10,000 pieces. I must admit that good quality Briti .......
413: Tube DIY Asylum, Re: Yea it kicks booty! (0.00)
Posted by Paul Barker on 2003-12-23, 15:16:09 (217.137.150.84)
Thanks Gordon, that's good enough for me. .......
414: Tube DIY Asylum, Re: TJ PX25 Anyone experienced it? (0.00)
Posted by Paul Barker on 2003-12-23, 15:14:17 (217.137.150.84)
The KR valve isn't a close enough substitute for a nos px25 so I have no interest in it. The Chinease ones to my knowledge are UX4 base. Maybe someone out there will get everything right eventually. : .......
415: Tube DIY Asylum, TJ PX25 Anyone experienced it? (0.00)
Posted by Paul Barker on 2003-12-23, 12:36:23 (217.137.168.54)
Looking to sell a px25 amp but don't want to let my precious nos go with it. So I'd have to supply the tj px25's with a gender changer so they fit a British 4 pin base (because the buyer needs to know .......
416: Tube DIY Asylum, Re: Lean back a little, J., (0.00)
Posted by Paul Barker on 2003-12-22, 01:26:24 (217.137.138.32)
Me too, I have to wade through the boxes of valves before I get to the bench, which like yours is a sort of lucky dip.. .......
417: Tube DIY Asylum, Re: A beautiful sight as well (0.00)
Posted by Paul Barker on 2003-12-19, 17:30:49 (217.137.132.40)
You're welcome any time Mark. I think we both recognised the differernce between the Rogers Radio Tubes Ltd (Toronto Canada) ar300a and the Great British stc (British leg of Western Electric) 212e. th .......
418: Tube DIY Asylum, Re: Obviously you're not married... (nt) (0.00)
Posted by Paul Barker on 2003-12-19, 10:24:55 (217.137.168.36)
Married to my old dutch for 23 years we have two young children 6yrs and 9yrs. .......
419: Tube DIY Asylum, And by the way (0.00)
Posted by Paul Barker on 2003-12-19, 10:20:52 (217.137.168.36)
The GM100 is put away under Darren's insistance. Yesterday I sold a cartridge and the guy came for a listen. So excited was I to show him a 212 that I did one of those impromptu fumbling juggling acts .......
420: Tube DIY Asylum, Re: Is that a 212? nt (0.00)
Posted by Paul Barker on 2003-12-19, 10:16:12 (217.137.168.36)
Yes the bottles in that picture are 4212H. These are not the best in my view. Here is a picture of the various bottles I have to try. Interesting thing, the best sound is the tallest valve and so it g .......
421: Tube DIY Asylum, Re: Toilet Roll (0.00)
Posted by Paul Barker on 2003-12-19, 06:05:17 (217.137.138.48)
yes I have no idea how that got there. Just bragging I suppose that we've come a long way since the outdoor toilet and the torn up newspaper hanging on a nail. .......
422: Tube DIY Asylum, Re: Photo of proto (0.00)
Posted by Paul Barker on 2003-12-19, 01:08:35 (217.137.138.19)
I like the way you breadboard, I use a similar semi permanent style, here is a picture of my present breadboard, it takes a long time to load. .......
423: Tube DIY Asylum, Re: 211 Schematic (comment) (0.00)
Posted by Paul Barker on 2003-12-18, 05:44:59 (217.137.150.19)
I checked all my 211's and none need their noses blowing. I suggest you send yours back. .......
424: Tube DIY Asylum, Re: A safety issue regarding CF driving into A2 region ????? (0.00)
Posted by Paul Barker on 2003-12-17, 12:16:43 (217.137.150.60)
A bias resistor parallel with a fast acting fuse or fusible resistor both on the filament ground link of 211. If the valve draws current fuse blow and amp reverts to cathode bias. .......
425: Tube DIY Asylum, Re: Gapping Ur Own Transformers (0.00)
Posted by Paul Barker on 2003-12-16, 00:41:25 (217.137.132.26)
No .......
426: Tube DIY Asylum, Re: Here's an idea for a really cheap 811A A2 design (0.00)
Posted by Paul Barker on 2003-12-14, 01:16:45 (217.137.138.20)
Yes you can derive the bias for the 811a from the cathode potential of the CF especially if the cf is choke loaded. The cathode bias for the cf would be stood above this, so you'd have a choke between .......
427: Tube DIY Asylum, Re: Series heaters for power tubes esp DHT?! (0.00)
Posted by Paul Barker on 2003-12-12, 07:13:50 (217.137.138.28)
Then rectify and current regulate the supply. .......
428: Tube DIY Asylum, Re: Series heaters for power tubes esp DHT?! (0.00)
Posted by Paul Barker on 2003-12-12, 00:56:57 (217.137.138.3)
Get a cheap torroid of whatever secondary voltage and wind your own secondary for 2.5v; centre tapped. .......
429: Tubes Asylum, Re: Pinout of 1619 Please? nt (0.00)
Posted by Paul Barker on 2003-12-08, 09:51:28 (217.137.138.36)
Right, thanks for the pointers Doug. .......
430: Tube DIY Asylum, Re: try both (0.00)
Posted by Paul Barker on 2003-12-08, 09:49:05 (217.137.138.36)
Bl**dy H*ll, give me a listen to Whitney through an Arcam Alpha 7 on CD please if a punch in the balls is the alternative! .......
431: Tubes Asylum, Re: Pinout of 1619 Please? nt (0.00)
Posted by Paul Barker on 2003-12-07, 12:21:33 (217.137.138.59)
Hi Doug, and many thanks. I just bought a few after talking to Gary Pimm at VSAC. Thought I'd give dhp pp a go. I managed to find some pt15's in the mean time, which are a better proposition. Just tho .......
432: Tubes Asylum, Pinout of 1619 Please? nt (0.00)
Posted by Paul Barker on 2003-12-05, 01:27:12 (217.137.138.27)
.......
433: Tube DIY Asylum, Re: PX4 PX25 212 Event this Saturday (0.00)
Posted by Paul Barker on 2003-12-04, 13:49:05 (217.137.132.127)
Yes, I forgot to thank you. Very much appreciated. Your photagraphy is excellent. Wish I had had a Leica when I was a photographer, trances the Nikon FM2 in my view. It will be good to catch up with y .......
434: Tube DIY Asylum, Re: the theory (0.00)
Posted by Paul Barker on 2003-12-03, 23:52:00 (217.137.132.35)
Well we've all been there with these thoughts. I used to talk about using Stereo 20 OPTS in low power SE because Johnathan Noble had done it and said it sounded good. Then one day I measured it and fo .......
435: Tube DIY Asylum, PX4 PX25 212 Event this Saturday (0.00)
Posted by Paul Barker on 2003-12-03, 23:33:18 (217.137.132.35)
I'm having a few friends over this Saturday, Darren Dean, Ali Tait, Nick G. Darren has a breadboard PX4 amp which he's bringing. I have a PX25 amp and a breadboard 212 amp. Four of us Brits came over .......
436: Tube DIY Asylum, Re: How to make a 'useless' iron useful.... (0.00)
Posted by Paul Barker on 2003-12-03, 00:50:29 (217.137.132.90)
At a guess I would say -3db 25hz to 12khz. MAx power at 25hz just a few watts, no dc current acceptable, expect midrange to sound muddy. Don't trust the enamel alone for isolation, pray that they used .......
437: Tube DIY Asylum, Re: ...errr , no ! (0.00)
Posted by Paul Barker on 2003-12-03, 00:47:19 (217.137.132.90)
They sounbd stonking at parfeed. .......
438: Tube DIY Asylum, Re: PSU with 0D3 VR tube question (0.00)
Posted by Paul Barker on 2003-12-02, 13:28:29 (217.137.132.143)
Only way is to use the vr as a voltage reference only to control a device that can handle the current. Normally the shunt device would be same power as the output device so this is a costly power supp .......
439: Tube DIY Asylum, Re: PX25 and poweramp schemas (0.00)
Posted by Paul Barker on 2003-11-28, 01:28:50 (217.137.138.11)
SE? B+ BIas resistor opt power noTE BIAS POINT 500v 1k 5k5 7w -45v 50mA 400v 550 3k2 6w -31v 62.5mA Drive first op point with an ECC33 Drive second op point with a 6J5 In ol .......
440: Tube DIY Asylum, Woops, another deliberate mistake (0.00)
Posted by Paul Barker on 2003-11-25, 08:13:00 (217.137.150.117)
Would be difficult to maintain required ripple with a decent shunt reg. Perhaps just one resistor one shunt reg and no caps. This would take further experimental experience, an RR filter. .......
441: Tube DIY Asylum, Erata 572b not 829b, mind elsewhere (nt) (0.00)
Posted by Paul Barker on 2003-11-25, 00:48:05 (217.137.132.17)
.......
442: Tube DIY Asylum, Re: Things are starting to get a little weird...... (0.00)
Posted by Paul Barker on 2003-11-25, 00:46:44 (217.137.132.17)
Hi, You are the fist live experience I have heard of a guy following the oh so simple hum cancellation technique Steve talks about, that is not to use inductive devices in PS so maintain phase angle s .......
443: Tube DIY Asylum, Re: Vintage or new? (0.00)
Posted by Paul Barker on 2003-11-25, 00:35:37 (217.137.132.17)
Yes I have to totally agree. .......
444: Tube DIY Asylum, Re: 2a3 Sovteks very good value for builders! (0.00)
Posted by Paul Barker on 2003-11-20, 14:47:56 (217.137.132.92)
I just wind my own secondary on a cheap mass market torroid. Sovtek 2a3 always has been and remains the best audio bargain this century. May have been knocked off it's pirch by the mesh plates for sou .......
445: Tube DIY Asylum, Re: The "Douglas" wave winder (transformer coil winder) (0.00)
Posted by Paul Barker on 2003-11-19, 13:54:23 (217.137.150.164)
There's a physical example of the hand cranked AVO coil winder in a glass acbinet in of all places our National Railway Museum, which is free entry in the city of York MOE. Worth studying if these thi .......
446: Tube DIY Asylum, Re: Yamamoto now has teflon GM70 sockets (0.00)
Posted by Paul Barker on 2003-11-19, 13:50:07 (217.137.150.164)
And a nice job you've done of it. Now I have one less excuse but still haven't heard the GM70! .......
447: Tube DIY Asylum, Re: Cathode follower (0.00)
Posted by Paul Barker on 2003-11-06, 14:26:52 (217.137.132.43)
He would be talking about an additional stage at the end of the existing circuit diagram I expect. The output impedance of a 12ax7 is high. It's a common tweak to the standard RCA phono stage. Cathode .......
448: Tube DIY Asylum, Re: Insulating the bolts that go down through a transformer??. . (0.00)
Posted by Paul Barker on 2003-11-04, 00:22:35 (217.137.132.80)
Good idea to do it and to use non magnetic stainless. .......
449: Tube DIY Asylum, Re: US no use to me... (0.00)
Posted by Paul Barker on 2003-11-03, 00:42:41 (217.137.132.114)
Sorry for the mistake. .......
450: Tube DIY Asylum, Re: a technology, sufficiently advanced, is indistinguishable from magic.... (0.00)
Posted by Paul Barker on 2003-11-03, 00:38:51 (217.137.132.114)
Well said. You could also turn it round and say there is just information and technology in magic. .......
451: Tube DIY Asylum, Re: don't even think about it... (0.00)
Posted by Paul Barker on 2003-11-01, 15:02:01 (217.137.138.62)
Been there done that worn the t shirt. Now I have a turns counter! Go get one soon as you can! .......
452: Tube DIY Asylum, Re: Compliments and questions..... (0.00)
Posted by Paul Barker on 2003-11-01, 14:52:16 (217.137.138.62)
You said "just imagine a lot of closed factories and out of business retailers for scenery" Sounds like Crayford in Kent when I left it for pastures new in the late '80's. Never looked back. There's h .......
453: Tube DIY Asylum, Don't forget CV57 and PT15 nt (0.00)
Posted by Paul Barker on 2003-11-01, 00:22:56 (217.137.132.83)
.......
454: Tube DIY Asylum, Mark Kelly ref 4212H's (0.00)
Posted by Paul Barker on 2003-11-01, 00:19:26 (217.137.132.83)
Dear Mark, It is such a shame this topic didn't come up before I flew to VSAC. I could have brought a pair of 4212H's in hand luggage. My problem is that these cost good money and they are very delica .......
455: Tube DIY Asylum, Re: Compliments and questions..... (0.00)
Posted by Paul Barker on 2003-10-31, 10:55:27 (217.137.132.152)
You can't stamp your own lams lets get that in perspective. I'm in MOE where are you? I can source poor quality M6 in MOE, it's all I can get easily. I haven't achieved obtaining better materials. I c .......
456: Tube DIY Asylum, Re: Positive Grid Votage (0.00)
Posted by Paul Barker on 2003-10-31, 00:53:43 (217.137.132.33)
Not a lot. Positive peaks of sign wave flatten, grid draws current altering bias makes further distortion from quiescent point. Should sound OK. .......
457: Tube DIY Asylum, Re: transformer mystery (0.00)
Posted by Paul Barker on 2003-10-31, 00:51:57 (217.137.132.33)
last item could be screen, but if it isn't don't blame me. .......
458: Tube DIY Asylum, Re: Make your own transfomer from scratch? (0.00)
Posted by Paul Barker on 2003-10-31, 00:49:18 (217.137.132.33)
Loads of people have tried and continue to wind their own. It is not very difficult to make a sweat sounding output transformer, it is difficult to make a best of class. CAreful with isulation between .......
459: Tube DIY Asylum, Re: Swap? (0.00)
Posted by Paul Barker on 2003-10-31, 00:25:27 (217.137.132.33)
It's a possibility, let me think about it. .......
460: Tube DIY Asylum, Re: 212E, 4212E, V1505E (0.00)
Posted by Paul Barker on 2003-10-30, 05:02:19 (217.137.138.1)
A couple of pairs? I'm into 2 figers but not as many as you have U19's over me. If anyone ios reading, no I am not selling. I don't sell full stop! .......
461: Tube DIY Asylum, Re: 212E, 4212E, V1505E (0.00)
Posted by Paul Barker on 2003-10-30, 00:26:14 (217.137.138.18)
Yes I remembered you talking about this, but when IslandPink came over we both really liked something about the AR300A's. Thes have a very large flat anode which completely obscures the grid. The fila .......
462: Tube DIY Asylum, Re: 212E, 4212E, V1505E (0.00)
Posted by Paul Barker on 2003-10-29, 09:33:29 (217.137.138.89)
The ones I have look same as earlier 4212's' that is taller glass envelope, same diameter same metal base. Later 4212's have squat envelope but same anode. Some 4212 have glass base, like an oversized .......
463: Tube DIY Asylum, Re: mmmm px25 (0.00)
Posted by Paul Barker on 2003-10-28, 07:55:40 (217.137.138.46)
I was in a great dilema on day one at VSAC. Brian had two of these with him on reduced price... I left 'em for someone else in the end. I'll use my four british made ones up before I start paying twic .......
464: Tube DIY Asylum, Re: Assorted Thoughts (0.00)
Posted by Paul Barker on 2003-10-28, 07:49:02 (217.137.138.46)
I know where you are coming from on '57's. I still haven't heard your speakers, shame none of the vsac exhibitors were using them. Maybe we could have heard their gear in a better light had they. Afte .......
465: Tube DIY Asylum, What we mean is (0.00)
Posted by Paul Barker on 2003-10-28, 01:46:33 (217.137.132.3)
Sorry, to expand this to the original poster. The reason that the value of the grid leak resistor can be too great is in respect of grid current. Using ohms law the greater the resistance, for any giv .......
466: Tube DIY Asylum, Re: Huh? (0.00)
Posted by Paul Barker on 2003-10-28, 01:37:02 (217.137.132.3)
I was thinking similarly. I was thinking of Fi primer circuit. I think we need to hear from actual users on this one, which I am not. .......
467: Tube DIY Asylum, Re: srpp 6sn7 coupling cap value to 300b? <nt> (0.00)
Posted by Paul Barker on 2003-10-28, 01:32:35 (217.137.132.3)
As you point out, with his 30k load resistor the 120k grid leak is now a compromise to power transfer from 6sn7 to 300b. The Fi primer uses 270k grid leak. Are we really sure that this isn't a safe va .......
468: Tube DIY Asylum, Re: srpp 6sn7 coupling cap value to 300b? <nt> (0.00)
Posted by Paul Barker on 2003-10-27, 09:02:14 (217.137.138.69)
What Grid Leak Resistor on 300b? What anode load for 6sn7? .......
469: Tube DIY Asylum, Re: Use other transformers or make my own? (0.00)
Posted by Paul Barker on 2003-10-22, 00:54:01 (217.137.132.17)
Not a good idea to re-use winding wire, the thin enamel is designed for one turn round a former and no more, straighten it out and bend it round a former a second time and it would not have the necess .......
470: Tube DIY Asylum, Re: RECTIFIERS: cathode-follower vs. non-cathode-follower (0.00)
Posted by Paul Barker on 2003-10-19, 01:04:06 (62.252.196.129)
You take voltage out from the filament or the cathode depending which the valve has. In the case of filament valves this involves a heater supply to the filaments which must float as it is at the B+ p .......
471: Tube DIY Asylum, Re: Yes... (0.00)
Posted by Paul Barker on 2003-10-16, 14:24:46 (62.252.201.157)
I recommend any entry level enthusiasts buy the 3rd edition even if they own the second. Old hands should know it anyway, but I found the 3rd useful so you'd have to be an older hand than me to not fi .......
472: Tube DIY Asylum, Re: Has any one here tried the 8212 tube? (0.00)
Posted by Paul Barker on 2003-10-16, 14:20:26 (62.252.201.157)
I was way off track then. I'll get out my GE Essential Characteristics. OK got it, looks interesting, you have a mu of 28 so in that sense it would be better than your 5687's mu of 17, and internal im .......
473: Tube DIY Asylum, Re: Has any one here tried the 8212 tube? (0.00)
Posted by Paul Barker on 2003-10-16, 01:16:37 (62.252.236.25)
Never heard of it. Tell me more? Any relation to 212/4212? .......
474: Tube DIY Asylum, Re: Later (0.00)
Posted by Paul Barker on 2003-10-09, 11:10:05 (62.252.237.15)
That's fine .......
475: Tube DIY Asylum, Re: Yep a CCS on the output of a push pull amp is the way to go. (0.00)
Posted by Paul Barker on 2003-10-09, 11:08:25 (62.252.237.15)
I heard it, and I normally Lean towards SE. I didn't detect any tonal loss against se, but we were not in a position to AB compare. It deserves personal experimentation. For myself I have so many SE T .......
476: Tube DIY Asylum, Re: What did you hear ? (0.00)
Posted by Paul Barker on 2003-10-09, 02:15:13 (62.252.240.174)
Oh yes when are you coming again? Shall I post the pcb's and the camera or wait for you? Look Mark there was so much I wouldn't like to do my review over the net, but there is plenty to talk about whe .......
477: Tube DIY Asylum, Re: Mocassins (0.00)
Posted by Paul Barker on 2003-10-09, 02:09:27 (62.252.240.174)
Nice one .......
478: Tube DIY Asylum, Re: Cascode Current Source (0.00)
Posted by Paul Barker on 2003-10-08, 08:28:47 (62.252.196.45)
I don't know but I have to you are right to question. I fried 12 successive DN2540's in this manner. Some people learn fast and some people take 6 goes at it! R and D is such fun. .......
479: Tube DIY Asylum, Re: Any VSAC reports yet... (0.00)
Posted by Paul Barker on 2003-10-08, 08:26:10 (62.252.196.45)
If vry is who I think he is we need to talk on the phone, because both items were close to my heart. As a teaser the GM100 turns out to have same sonic qualities as 212. Alan's stuff sounded excellent .......
480: Tube DIY Asylum, Re: Pommy VSAC! (0.00)
Posted by Paul Barker on 2003-10-08, 08:20:47 (62.252.196.45)
I'll support it .......
481: Bottlehead Forum, Re: VSAC thank yous and personal highlights (0.00)
Posted by Paul Barker on 2003-10-08, 07:51:26 (62.252.196.45)
Thanks for a great event and such warm hospitality from your team and everyone there. The opportunity to talk face to face with you all across the pond was of no small significance, and should clarify .......
482: Tube DIY Asylum, Re: Questions about using Gas Regulator tubes (0.00)
Posted by Paul Barker on 2003-10-01, 00:14:51 (62.252.236.129)
I'm using them on the VA section of 6em7. I haven't detected a down side with my ears, which is what matters. .......
483: Tube DIY Asylum, Re: which is the right way ? tubes expert please . (0.00)
Posted by Paul Barker on 2003-09-18, 00:54:41 (62.252.240.143)
Yes 100k resistor from grid to ground. Out of interest Morgan Jones once said words to the effect of "as far as I'm conscerned all amplifiers should have a 1 meg input impedance". So 100k is conservat .......
484: Tube DIY Asylum, Re: Understanding transformer voltages (0.00)
Posted by Paul Barker on 2003-09-09, 14:08:11 (62.252.196.247)
Are you in Britain? Just thought you might be as you are quoting from Maplin, or is that an international organisation? Anyway if you are in Britain I can probably find something suitable you can have .......
485: SET Asylum, Re: And a lot of heat! <nt> (0.00)
Posted by Paul Barker on 2003-09-09, 13:59:49 (62.252.196.247)
It's quite nice in my room to have that little bit of heat from the 212's, Gm100's? now that would be overkill. .......
486: Bottlehead Forum, Re: VSAC Registration (0.00)
Posted by Paul Barker on 2003-09-09, 13:48:37 (62.252.196.247)
Oh thanks for that Doc, I felt sure there would be a warm welcome. I'll just pay on the door then to keep it easy. I think I have accomodation sorted but thanks for that help also. I'll check it's org .......
487: Tube DIY Asylum, Re: Understanding transformer voltages (0.00)
Posted by Paul Barker on 2003-09-09, 13:43:21 (62.252.196.247)
This sounds stupid. The schematic you are following states 2 X 100v, which is a very poor way of saying 200vct. Another way to describe it is 100 - 0 - 100. I didn't say parallel the two secondaries. .......
488: Tube DIY Asylum, Re: Understanding transformer voltages (0.00)
Posted by Paul Barker on 2003-09-09, 10:19:16 (62.252.236.227)
Hello again. You need a cheap torroidal transformer with two 100v (110v or something else close) secondary windings connect them with the end of one winding attached to the start of the other. This th .......
489: Bottlehead Forum, VSAC Registration (0.00)
Posted by Paul Barker on 2003-09-09, 00:42:15 (62.252.200.191)
Doc, Eileen? Help? I can't register for vsac on your shopping cart system because even though I enter UK and country it only offers USA states. Then even if I use the one which is Armed Forces Canada .......
490: SET Asylum, Re: SET at 40 watts or more possible? (0.00)
Posted by Paul Barker on 2003-09-05, 12:49:28 (62.252.240.168)
40 watt in A1 75 watt in A2 amp using 212. It's a cross between an 845 and a 211 on steroids. .......
491: Tube DIY Asylum, Re: Where would diodes make the most difference (0.00)
Posted by Paul Barker on 2003-09-01, 01:25:55 (62.252.240.242)
Not sure what SK3925 is, it might be a 2000 Peak Inverse volt 1 amp diode but check before taking my word for it. You can series connect fred's to make up piv of 2,000v to replace this item. The 1n400 .......
492: Tube DIY Asylum, Re: pse amp vs se amp (0.00)
Posted by Paul Barker on 2003-08-28, 13:04:58 (62.252.238.115)
Well I've got the HT transformer so far. Yes the filaments are hungry aren't they. What a daft idea. The more I think about it the more I wish I hadn't bought those GM100's, but I got them while I cou .......
493: Tube DIY Asylum, Re: pse amp vs se amp (0.00)
Posted by Paul Barker on 2003-08-28, 00:46:38 (62.252.236.60)
There is also lying around a push pull output transformer about the size of a 3kva power transformer, which I assume came from some mamouth PA system of yor or something like that. I doubt that the fr .......
494: Tube DIY Asylum, Re: pse amp vs se amp (0.00)
Posted by Paul Barker on 2003-08-28, 00:37:09 (62.252.236.60)
Well I have enough 212's but man that is far too showy for me. I keep meaning to breadboard the copper anode GM70, 'cause I have a sneaky idea that I don't need to burn 212's at all. Not sure as yet, .......
495: Tube DIY Asylum, Re: pse amp vs se amp (0.00)
Posted by Paul Barker on 2003-08-27, 13:00:40 (194.164.15.179)
This is true .......
496: Tube DIY Asylum, Re: pse amp vs se amp (0.00)
Posted by Paul Barker on 2003-08-27, 00:49:20 (62.252.236.214)
No because the law of diminishing returns sets in. A single 212 gives 40 watts in A1. That output transformer is a challenge to build so as not to compromise the gains made in using such a great sound .......
497: Tube DIY Asylum, Re: pse amp vs se amp (0.00)
Posted by Paul Barker on 2003-08-26, 00:44:59 (62.252.196.42)
I breadborded a 211 amp, which I really liked more than most other things I've heard. The 211 has a very sweet characteristic, which demonstartes hardess in lesser valves. Then I tried the 212. It was .......
498: Tube DIY Asylum, Re: pse amp vs se amp (0.00)
Posted by Paul Barker on 2003-08-25, 09:30:47 (62.252.197.155)
Are you talking about dual plate 2a3/6a3/6b4g Dave? They sound amaisingly good under the circumstances, and a testimony to the viability of parallel dht's. I enjoy the sound of a pair of 211's more so .......
499: Tube DIY Asylum, Re: Does a transformer for output or input block DC. . (0.00)
Posted by Paul Barker on 2003-08-21, 13:33:49 (62.252.200.231)
Only if it is intended to. Some input transformers arer isolating but cannot accept dc potential across them. Some transformers are auto formers (not isolating). Best to check in each particular case. .......
500: Tube DIY Asylum, Re: Do you know why Audio Note classify C-core a higher class of OPT ? (0.00)
Posted by Paul Barker on 2003-08-19, 00:52:18 (62.253.8.27)
Yes, I agree the bigger problem is the Leakage Inductance, but the more you chase one parameter there comes a time things become worse overall because of the other factors rearing up. On the whole I d .......
Found total of 500 records, Query: , Author: Paul Barker in All Forums, Time: 1 sec.