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1: Tube DIY Asylum, Re: Ping MFC re Frayne paper (0.00)
Posted by mfc on 2005-08-06, 18:20:27 (4.242.219.159)
Hi, When I came into the discussion, it was about: 1) Triodes don't produce higer order harmonics The Frayne paper shows a Maclaurin series expansion for plate current containing higher order harmonic .......
2: Tube DIY Asylum, Re: Not so simple (0.00)
Posted by mfc on 2005-07-31, 14:54:41 (4.242.216.168)
Hi Dave, Good post. Makes me toss this out as an observation... 1) A device (like a triode) that produces inherently 2nd and 3rd harmonics will also produce 4th, 5th, 6th, 7th, etc...but these higher .......
3: Tube DIY Asylum, Re: I don't understand (0.00)
Posted by mfc on 2005-07-30, 20:07:30 (4.242.219.135)
Sorry for the late post. >I can find no evidence that the-triode-plate-effect-which-you-call- >NFB-and-I-don't expands the order of harmonics John G. Frayne, "The Unilateral Dynamic Characteristics of .......
4: Propeller Head Plaza, Re: Nice post.... (0.00)
Posted by mfc on 2004-03-31, 19:47:00 (4.242.216.45)
Hi, >It would be interesting add level to the equation to create a 3-D >distortion profile by plotting the harmonics on one axis, the level >on the second, and the % dist on the third (vertical) axis. .......
5: Propeller Head Plaza, Re: "inherent negative feedback" what are you talking about? (0.00)
Posted by mfc on 2004-03-13, 10:11:35 (67.75.231.47)
Hi, Here is a link to a well regarded amplifier using local feedback on a pentode to produce "triode-like" curves. Local feedback comes from R5/R6 which are also doing double duty in supplying plate c .......
6: Propeller Head Plaza, Re: nomographs for the braid in braid construction (0.00)
Posted by mfc on 2004-02-28, 11:37:15 (67.75.215.162)
Hi, Very interesting cable discussion. Nice to see the graphs illustrating the relationships between the parameters. A lot of hard work, but very interesting. One question: Why such a focus on minimiz .......
7: Propeller Head Plaza, helpful hint for math (0.00)
Posted by mfc on 2004-02-23, 21:41:05 (67.75.231.5)
Hi, Its easy to do superscripts or subscripts or even tables of numbers using Front Page express (if you are using Windows). Just write some text and formulas on the Normal tab, then go ove .......
8: Tube DIY Asylum, Re: It shifts down to 4.5k! (0.00)
Posted by mfc on 2004-02-21, 19:05:44 (67.75.231.62)
>but at high levels the 2d decreases with load as expected, at low >levels it decreases, then increases ie shows a null... thats a new >one to me. Me too. I didn't spot it the first time at all. The d .......
9: Tube DIY Asylum, 2A3 (0.00)
Posted by mfc on 2004-02-21, 18:51:13 (67.75.231.62)
Here is a 2A3 for a couple of large and small signal levels. The minima disappears at the lowest signal level, but at least it is constant at the large signal levels and at a useful RL (3K). width:3 .......
10: Tube DIY Asylum, 300B revised (0.00)
Posted by mfc on 2004-02-21, 17:03:03 (67.75.230.147)
Revised 300B showing how sensitive the minima is to level. At low levels the minima seems to disappear. Also at low levels, the 2nd harmonic is showing a minima. The other interesting thing is at larg .......
11: Tube DIY Asylum, a little more complicated (0.00)
Posted by mfc on 2004-02-21, 14:09:13 (67.75.215.254)
because the 2nd goes down, but the 3rd doesn't go down by the same degree. Would like to know why the 3rd does this. It must have to do with where the operating point is positioned on the plate curves .......
12: Tube DIY Asylum, These don't move (0.00)
Posted by mfc on 2004-02-21, 11:59:55 (67.75.230.186)
Hi Mike, Sounds good idea to look at. Here are the results side by side for low and hi volume on a 2A3 and 300B. The 300B 3rd seems to wander a bit. The 3rd distortion on these don't move down like th .......
13: Tube DIY Asylum, Re: It shifts down to 4.5k! (0.00)
Posted by mfc on 2004-02-21, 11:04:08 (67.75.230.186)
Hi again, >and there also appears to be a null in the 2nd at the low power >points... This one is because reducing the input by 10x means that the signal moves over a much smaller segment of the plate .......
14: Tube DIY Asylum, Re: It shifts down to 4.5k! (0.00)
Posted by mfc on 2004-02-21, 10:42:17 (67.75.230.186)
Hi, >its an interesting concept, but not worth chasing. Definitely a concept not suitable for use in reproducing multiple units in manufacturing. Might be good for DIY though. I wonder if this null is .......
15: Tube DIY Asylum, It shifts down to 4.5k! (0.00)
Posted by mfc on 2004-02-20, 21:26:15 (67.75.215.181)
Very interesting. That was what Datubie said was the recommended value. Here are the results. width:96pt">Conditions Vin 6 6 B+ 400 400 Ib (ma) 60 60 Load DCR 5x45 yes"> 2nd 5x .......
16: Tube DIY Asylum, Would you believe... (0.00)
Posted by mfc on 2004-02-20, 20:49:33 (67.75.230.181)
Hi, I don't have a model for a DA30. So I found that 5x 45s hit the operating point of 60ma and 400v with a bias of 100v right on the head. Rp at this point was 577 ohms. So this *may* be a good appro .......
17: Tube DIY Asylum, Re: 5K OPT (0.00)
Posted by mfc on 2004-02-20, 08:54:17 (67.75.230.132)
Hi, This is the parallel lines model as shown at the link below. Everything is constant so no null is produced. .......
18: Tube DIY Asylum, Re: Now for a DA30.... (0.00)
Posted by mfc on 2004-02-20, 08:49:39 (67.75.230.132)
What current? It isn't something you can plug in generically and get an answer since it depends heavily on particular parameters: tube Rp value, operating point, the circuit, transformer DCR, Load rea .......
19: Tube DIY Asylum, Re: 5K OPT (0.00)
Posted by mfc on 2004-02-19, 22:39:15 (67.75.215.194)
Hi Mike, Yeah. At least I was modeling transformer reactance (50H in simulations). Reactive loads and transformer cores :( time to quit. Reality is the best simulation. Thanks for finding something re .......
20: Tube DIY Asylum, Re: 5K OPT (0.00)
Posted by mfc on 2004-02-19, 19:32:36 (64.158.122.4)
Hi, As you say, your models may not have the non-linear variation in Rp and Gm which adequately captures the 3rd order minima effect. In other words, models where the plate curves have constant Vg lin .......
21: Tube DIY Asylum, Re: Simulation or measured? (0.00)
Posted by mfc on 2004-02-18, 09:28:08 (67.75.231.61)
Hi, >Does that mean that the B+ and running current was being changed >bythe pgm to optimise power output at each load variation? Otherwise >power out would be changing quite significantly with consta .......
22: Tube DIY Asylum, Re: Simulation or measured? (0.00)
Posted by mfc on 2004-02-17, 20:28:54 (64.158.120.114)
Hi Allen, What operating point were you using? Thanks .......
23: Tube DIY Asylum, Re: Some useful equations (0.00)
Posted by mfc on 2004-02-17, 09:14:08 (67.75.231.78)
I should have said approximations. Didn't know if you had seen or not. Do you have a pointer to a paper or book showing a better approximation? Mike .......
24: Tube DIY Asylum, Re: Some useful equations (0.00)
Posted by mfc on 2004-02-16, 21:34:44 (64.158.122.8)
hi, I got a paper by Frayne, Dec 1920, "The Unilateral Dynamic Characteristics of Three-Electrode Vacuum Tubes". It discusses this effect of increasing RL only in terms of plate current maximas. In ou .......
25: Tube DIY Asylum, Some useful equations (0.00)
Posted by mfc on 2004-02-16, 21:04:30 (64.158.122.8)
g m = d I p / d Ec = 3/2*K 2/3 I 1/3 r p = d Eb/ d I p = 2/3*mu*K -2/3 I -1/3 where: I p is plate current Eb is plate to cathode voltage Ec is grid to cathode voltage .......
26: Tube DIY Asylum, 3rd harmonic minima in push pull (0.00)
Posted by mfc on 2004-02-15, 19:25:26 (67.75.230.170)
Curious to see if the 3rd and higher order distortion null occurs in Push pull with increasing RL. Setup a simulation using Glassware new Push pull calculator (no affiliation but a good set of product .......
27: Propeller Head Plaza, Thanks - nt (0.00)
Posted by mfc on 2004-02-15, 16:05:55 (67.75.230.170)
nt .......
28: Tube DIY Asylum, Thanks for this >NH< (0.00)
Posted by mfc on 2004-02-14, 20:08:52 (67.75.215.191)
nothing here .......
29: Propeller Head Plaza, Re: Sounds right (0.00)
Posted by mfc on 2004-02-14, 15:59:50 (67.75.215.180)
>Actually this cancellation of delta Rp and delta Gm in triodes has >been around for a long time I think you are referring to the effect produced by introducing local feedback? Local feedback lineariz .......
30: Propeller Head Plaza, Re: Sounds right (0.00)
Posted by mfc on 2004-02-14, 10:28:42 (67.75.231.22)
Hi, Definitely confused by two seperate phenomena with similiar results. With increasing local feedback, the 2nd harmonic marches steadily downward, while the 3rd and above go thru local *maximas*. Wi .......
31: Tube DIY Asylum, Re: Complex linear = opaque, but simple distortion = transparent? (0.00)
Posted by mfc on 2004-02-14, 09:51:44 (67.75.231.89)
>whem we ear live sounds ( ou live music) you are also earing with >your natural (intrinsec) distortions of your ears When you watch that live performance, you are watching it with your eye/brain fill .......
32: Tube DIY Asylum, Re: Complex linear = opaque, but simple distortion = transparent? (0.00)
Posted by mfc on 2004-02-13, 21:15:46 (67.75.230.223)
Hi, Low distortion may be one approach, but as kurt suggests, there may be another way as well. If the ear itself produces distortion, the question is, why don't we hear it? Maybe it is like a blind s .......
33: Propeller Head Plaza, Re: Sounds right (0.00)
Posted by mfc on 2004-02-13, 19:25:21 (67.75.215.174)
Hi, >negative 3'rd harmonic can cancel positive 3'rd harmonic Is there an implication that evens don't cancel? This would be 'odd' in light of PP circuits which cancel events. I don't see why only odd .......
34: Propeller Head Plaza, Re: Sounds right (0.00)
Posted by mfc on 2004-02-12, 15:40:02 (205.238.9.194)
Hi, >but how does the change in 2nd harmonic compare to the behavior of >the 3rd That is why this mechanism reminded me so much of feedback. Because it also has steadily decreasing 2nd and no minima j .......
35: Propeller Head Plaza, Re: Something kinky in the transfer function? (0.00)
Posted by mfc on 2004-02-12, 14:06:01 (205.238.9.194)
Hi, Very good way of looking at it. There are two parameters moving in opposite directions of each other and they are non-linear. Rp is moving downward with increasing current in a non-linear manner. .......
36: Propeller Head Plaza, 3rd harmonic minima (0.00)
Posted by mfc on 2004-02-11, 20:26:26 (67.75.230.139)
Hi, An interesting effect that I can't explain. Wondered if anybody here has run into this... The 271a tube (datasheet at link below) shows the effect of increasing Load resistance on distortion. Page .......
37: Tube DIY Asylum, Re: NOT IN MY EXPERIENCE (0.00)
Posted by mfc on 2004-01-10, 14:54:29 (67.75.231.58)
In the case of regulating B+, the goal is to get the "effective" DCR of the supply as low as possible. In the case of a CCS, the goal is to get the "effective" DCR as hi as possible. I don't see how a .......
38: Tube DIY Asylum, Re: LOOK at the Coolest Product and VERBAGE...here ! (0.00)
Posted by mfc on 2004-01-10, 11:38:32 (67.75.230.208)
You may have a general rule of thumb, but another way to get micro detail may be to isolate the Power supply from the Active stages in the first place. A CCS seems to provide similiar improvements in .......
39: Tube DIY Asylum, Re: On third harmonic minima . (0.00)
Posted by mfc on 2004-01-10, 11:28:26 (67.75.230.208)
>Mathematically, this is because second harmonic is caused by the >slope of the gain equation (the first differential) and third by its >curvature (the second differential) and this can be extended to .......
40: Propeller Head Plaza, Re: But is recording technique getting better? (0.00)
Posted by mfc on 2003-08-22, 11:26:46 (67.75.231.70)
20usec is 50Khz. In order to accurately preserve timing info, does that mean 10x... so 500Khz? How many cables have good characteristics up in this range? .......
41: Propeller Head Plaza, Re: But is recording technique getting better? (0.00)
Posted by mfc on 2003-08-22, 11:05:58 (67.75.231.70)
I really can't hear a direct tone much above 14Khz. Which makes me think that how we "hear" above 20Khz is by changes in image location and size and shape. Why else have two ears, if not to hear these .......
42: Tech Square, Re: Agree with you.. but there is more.... (0.00)
Posted by mfc on 2003-08-08, 10:18:26 (67.75.231.12)
Hi, >Everything seems quicker, tighter and faster - less bass, but good >quality stop/start bass. The depth of the sound stage >foreshorthened - sort of like SS. Ahhh, this sounds familiar. I think I .......
43: Tech Square, Re: Speed kills warmth and three dimentionality...... (0.00)
Posted by mfc on 2003-08-08, 00:16:59 (67.75.231.121)
Hi, I wouldn't make this generality. I haven't found this to be the case. The particular tweaks you have applied maybe limited in what they can do. I've found *generally speaking* that warmth, depth i .......
44: Tech Square, Re: Been there..... (0.00)
Posted by mfc on 2003-08-07, 14:18:49 (67.75.231.10)
Hi, >Have gone with a polyolefin webbing over the wire to hold the twist Not visualizing this. Is it an insulating jacket over both wires? What insulation is on the wire? .......
45: Tech Square, Re: Been there..... (0.00)
Posted by mfc on 2003-08-07, 11:51:51 (67.75.231.77)
Yes, Trying to rule out the mechanical resonance effects however. These can be air borne, coming thru the floor, internally generated. Try to leave resonance alone and constant... put cables on good r .......
46: Tech Square, Re: OK, how about them cable risers? (0.00)
Posted by mfc on 2003-08-07, 10:36:26 (67.75.231.77)
If it is dielectric. I wonder if putting the cable near a poor dielectric makes it worse. One experiment would be to use your good cable risers, but simply attach some electrician tape to the cable fo .......
47: Propeller Head Plaza, Re: Input Intercept Plots (0.00)
Posted by mfc on 2003-08-07, 10:21:58 (67.75.231.77)
Hi, The more I think about this, the more it seems like this should really characterize the linearity - especially low level. Seems like it would be a lot of work to do for 2nd, 3rd, up thru 7th. Any .......
48: Tech Square, Re: This forum (0.00)
Posted by mfc on 2003-08-06, 19:47:19 (67.75.231.79)
Hi, After reading Steve a bunch of times and wondering where he was coming from...I wouldn't call it subjective/objective...it looks more like a global/local argument. The local point of view means th .......
49: Tech Square, Re: I'm not sure that would differentiate... (0.00)
Posted by mfc on 2003-08-05, 15:10:29 (67.75.230.132)
Hi, >If the effect were due to mechanical resonance, the big change would >occur when the cable came up off the carpet. Additional height >shouldn't make much difference. But if it were due to fields, .......
50: Tech Square, Re: OK, how about them cable risers? (0.00)
Posted by mfc on 2003-08-05, 02:07:19 (67.75.231.114)
Yeah, one thought that crossed my mind is it may be related to DA. Moving the cables away from the carpet/floor, reduces the carpet/floor contribution to this effect. It might be tested by actually wr .......
51: Propeller Head Plaza, Re: Phi Multitone test signals (0.00)
Posted by mfc on 2003-08-05, 01:59:52 (67.75.231.114)
Hi, >multitone IM should be very sensitive to lower level distortion Thanks John. This test seems like a bit of a black box as to how it gets at low level distortion. The band limited square produces .......
52: Propeller Head Plaza, Re: Phi Multitone test signals (0.00)
Posted by mfc on 2003-08-04, 21:27:22 (67.75.230.248)
Hi, I didn't realize you were the author. Thanks! .......
53: Propeller Head Plaza, Re: Phi Multitone test signals (0.00)
Posted by mfc on 2003-08-04, 17:13:14 (67.75.230.240)
So far it has been a great test. It's easy to seperate out the square wave harmonics from the sine wave harmonics - no problem, since the particular frequencies don't step on each other. What's a Phi .......
54: Propeller Head Plaza, Phi Multitone test signals (0.00)
Posted by mfc on 2003-08-04, 13:32:49 (67.75.230.214)
Hi, How would you compare/contrast these to a large bandlimited square wave with small sine wave test (similiar to what was in JCs article). I've liked this test so far because I can get a decent rise .......
55: Tube DIY Asylum, Re: The 47P-P vs the 300B SET, the saga continues... (0.00)
Posted by mfc on 2003-08-03, 22:52:30 (67.75.231.124)
Keep up the great work. You've got that pioneering spirit and are really pushing the envelope. .......
56: Propeller Head Plaza, catch-22 (0.00)
Posted by mfc on 2003-08-02, 23:38:20 (67.75.231.37)
. .......
57: Propeller Head Plaza, Caution - detour ahead (0.00)
Posted by mfc on 2003-08-02, 21:44:19 (67.75.231.37)
Just to make sure I wasn't missing something, I checked the ultrasonic range of harmonics. Interestingly, each circuit has its own profile in this range. I'm not sure what conclusions can be drawn fro .......
58: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-08-02, 20:00:19 (67.75.231.125)
Hi Scott, I don't know of McDonald's work on Super Linear cathode followers. What I meant is did McDonald discover the Cascode emitter follower aka Hawksford cascode aka Baxandall super pair? I'd rath .......
59: Tube DIY Asylum, Re: 47PP on Oris 150 horns (0.00)
Posted by mfc on 2003-08-02, 19:48:03 (67.75.231.125)
Hi Kurt, I heard an earlier rev of Gary's amp over at his house. I think it was the 3/22 version with the pentode driver and input transformer coupled. It was the fastest/holographic/detailed/biggest .......
60: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-08-02, 18:33:54 (67.75.231.125)
Hi, >the "best" CF/EF/SF was a CCS cascode, as pioneered by McDonald and >a few others in the late '50s. Is this the Hawksford/Baxandall cascode? .......
61: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-08-02, 14:20:19 (67.75.230.200)
Hi, >>"So what about at the hi-feedback end of the spectrum. Say we are >>careful about TIM and stability, what other problems are there in >>this case?" >That is what we are cooking here this month. .......
62: Propeller Head Plaza, Re: Thanks for the info.... (0.00)
Posted by mfc on 2003-08-02, 12:30:15 (67.75.230.175)
Hi, >I am having some luck, believe it or not, with 6550 beam tubes using >*local* feedback Very interesting. The pentode with local feedback could actually be a more linear triode than a triode. How .......
63: Propeller Head Plaza, Re: Golden Ears and Audible Differences: A New Test (0.00)
Posted by mfc on 2003-08-01, 22:33:49 (67.75.215.143)
Why are these cable discussions like bar room brawls? .......
64: Propeller Head Plaza, Re: That is fascinating! (0.00)
Posted by mfc on 2003-08-01, 22:32:00 (67.75.215.143)
Hi, >But then you only added a little bit of degeneration to one of the >two tubes to get the sound you wanted. Yes, added a tiny resistor to the output tube cathode and it made a large difference in .......
65: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-08-01, 19:51:38 (67.75.231.42)
Hi, >But using lots of feedback guarantees a wideband harmonic residue. >Granted, it will be buried in the noise floor, but it's there. ...and since a triode has builtin negative feedback, these same .......
66: Propeller Head Plaza, Resistors (0.00)
Posted by mfc on 2003-08-01, 19:31:29 (67.75.231.42)
Hi, Are any brands better for distortion. How about the super resistors like Vishay or Caddock? How about types like WW or metal film, carbon comp? .......
67: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-08-01, 13:00:49 (67.75.231.118)
Thanks Scott, One theory about why my "no feedback" amp sounds good is because all the hi-order harmonics are not just way down (>90dB), but way, way down (>120dB). I only have an uncal'd HP-334 and t .......
68: Propeller Head Plaza, Re: Going to the moon... (0.00)
Posted by mfc on 2003-08-01, 11:17:50 (67.75.231.33)
Hi, I really like the sound. >Let's assume for a moment that the circuit sounds much better >without the degeneration, even though the measurements are basically >the same. Then you would still have t .......
69: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-08-01, 02:04:54 (67.75.215.187)
Here are the results for varying the top resistor. I also readjusted the compensation cap for flat frequency response. width:74pt"> Harmonic Reference Out 1VPeak Sine 20ohm/2520pF 50o .......
70: Propeller Head Plaza, Re: I'm a black and white kind of guy... (0.00)
Posted by mfc on 2003-08-01, 00:07:49 (67.75.215.187)
>I don't think I've ever heard a well executed tube amp without >feedback. Have you? Could be interesting... Well I can't resist that... Disclaimer: I hold nothing against feedback or its intended use .......
71: Propeller Head Plaza, Re: Thoughts... (0.00)
Posted by mfc on 2003-07-31, 22:11:30 (67.75.230.220)
Hi, I have built up stuff with tubes. Now my aim is to find some guiding principles that perhaps the "blameless amp" crowd has missed. I'd like to go beyond the flavor of the month capacitor approach .......
72: Propeller Head Plaza, When does the movie come out? (0.00)
Posted by mfc on 2003-07-31, 21:37:11 (67.75.230.220)
You guys should write a book first :) I notice in D. Self's book that he has a triple EF output stage in Figs 5-13, 5-25 page 122,136. Then later, Fig. 6-16 page 176 he goes back to a conventional dou .......
73: Propeller Head Plaza, partial bootstrap (0.00)
Posted by mfc on 2003-07-31, 21:03:14 (67.75.230.220)
Hi, Here is a partial bootstrap variation. I noticed in simulation that Q1 had small negative base current on the tips of the negative swing of the signal. Also wanted to eliminate the compensation. S .......
74: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-07-31, 13:09:32 (67.75.230.214)
Hi, I found something: IM 2 =a 2 /a 1 *U, HD 2 =1/2*a 2 /a 1 *U where a 2 , a 1 are coefficients. U is signal amplitude. and IM 3 =3/4*a 3 /a 1 *U 2 , HD 3 =1/4*a 3 /a 1 *U 2 IM 2 =2HD 2 , IM 3 = .......
75: Propeller Head Plaza, Re: What exactly is... (0.00)
Posted by mfc on 2003-07-31, 12:47:55 (67.75.230.214)
Here it is. V4 is just there to eliminate any need for a coupling capacitor which removes the need to move the simulation window way out past the point where this cap would DC stabilize. Note that the .......
76: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-07-31, 11:50:53 (67.75.230.214)
Its a split +- 20v supply (simulated). I'll try some different values for the top. .......
77: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-07-31, 11:01:55 (67.75.230.130)
Hi, The top, bottom resistor or both? I'm using 50 ohms on the top and 10 on the bottom currently. .......
78: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-07-31, 10:42:57 (67.75.230.130)
Hi again, >IM distortion is powerful, but it is not really better than harmonic >distortion I'm not grocking this statement. >You will notice that a triple-tone IM component is the most >sensitive of .......
79: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-07-31, 10:34:54 (67.75.230.130)
Hi JC, >leads to adding compensation, and thereby slowing the gain bandwidth >of the total circuit below that of a simple follower. This actually makes sense to me. Considered as part of a global feed .......
80: Propeller Head Plaza, Re: transient test - Part II (0.00)
Posted by mfc on 2003-07-30, 23:45:09 (67.75.230.207)
Hi, Yeah, I'm Mr. multi-media now by adding links to graphs and embedded tables. It works best to edit a page using uSoft front page, switching to the html tab and then cutting and pasting the html in .......
81: Propeller Head Plaza, transient test - Part II (0.00)
Posted by mfc on 2003-07-30, 21:52:14 (67.75.231.51)
Hi, Been looking at differences between a simple cathode follower and a skiklai follower, trying to understand them. Input uses bandlimited (27th harmonic) square wave of 1050Hz at 7V peak combined wi .......
82: Propeller Head Plaza, aural illusion? (0.00)
Posted by mfc on 2003-07-30, 17:49:11 (67.75.231.42)
Hi Steve and others, Been thinking about whether being able to hear changes in audio systems is actually mostly a psychological phenomena or is their something physically (objective) underneath it. If .......
83: Propeller Head Plaza, Re: IM is the elephant... (0.00)
Posted by mfc on 2003-07-29, 18:05:20 (67.75.231.24)
Most of the IM turns out to be from a slight overload problem. I analyzed the frequency graph in terms of what each component meant. Here is a breakdown from 13F1 to 3F2. F1=1050Hz square wave (out t .......
84: Asylum Feedback/Support, It works at 5:55pm on Tuesday July 29 (0.00)
Posted by mfc on 2003-07-29, 17:53:08 (67.75.231.24)
Thanks! .......
85: Asylum Feedback/Support, Re: image gallery (0.00)
Posted by mfc on 2003-07-26, 19:42:15 (67.75.230.250)
When I click view photo album, nothing is shown. I can't delete anything so it looks like a catch-22. .......
86: Asylum Feedback/Support, image gallery (0.00)
Posted by mfc on 2003-07-26, 17:26:30 (67.75.230.148)
Hi, I created a gallery today and uploaded a 53kb image. Now I get this message: Upload is not allowed! You have exceeded your storage limits, please delete some images when I try and look at my messa .......
87: Propeller Head Plaza, Re: Hunter in the woods (0.00)
Posted by mfc on 2003-07-26, 17:11:54 (67.75.230.148)
Getting at the truth involves exchange of ideas as well as rigor. Each is neccessary, but not simultaneously. I agree that testing is important, not in the early stages of development. As things progr .......
88: Propeller Head Plaza, The file is 53kb (0.00)
Posted by mfc on 2003-07-26, 16:51:43 (67.75.230.148)
and all I get is the yo-yo now??? .......
89: Propeller Head Plaza, try it (0.00)
Posted by mfc on 2003-07-26, 15:24:08 (67.75.231.118)
here it is .......
90: Propeller Head Plaza, Re: IM is the elephant... (0.00)
Posted by mfc on 2003-07-26, 15:21:35 (67.75.231.118)
Hi Scott and any others who might be interested, Take a look at the Sziklai frequency sweep. 10 ohm || .2uF load 1050 Square wave (first 27 harmonics) 8v peak 5Khz Sine wave 1v peak The offscale peaks .......
91: Propeller Head Plaza, Re: Cap loaded (0.00)
Posted by mfc on 2003-07-26, 14:58:45 (67.75.231.118)
Hi, >Did you remove the RL? This is with the RL (10 ohms || 14uH). Note that adding the RL reduced the comp cap need from 3900pF (with no capacitor load) to 2500pF for flat frequency response. Pulling .......
92: Propeller Head Plaza, Re: Hunter in the woods (0.00)
Posted by mfc on 2003-07-26, 14:31:24 (67.75.231.118)
Hi, >Only that at some point, the comparisons be done without your >knowing the identity of what it is you're listening to. OK, just like if I wanted to use a particular rule of thumb or equation, or .......
93: Propeller Head Plaza, Re: Cap loaded (0.00)
Posted by mfc on 2003-07-26, 12:13:58 (67.75.230.175)
Hi Scott, >And if you increase the C-load beyond .6uF does the peak subside? It looks like a pole. The pole moves down in frequency and the peak gets higher as C is increased. Interestingly, no ringin .......
94: Propeller Head Plaza, Re: Hunter in the woods (0.00)
Posted by mfc on 2003-07-26, 11:37:32 (67.75.230.216)
Hi, This seems to be an inescapable dilemma. How can a test be made to produce better conditions under which to evaluate changes? It seems to me that many tests are misguided. For instance: Evaluating .......
95: Propeller Head Plaza, Re: Hunter in the woods (0.00)
Posted by mfc on 2003-07-25, 22:42:53 (67.75.231.101)
Hi, >I just don't see how the approach negates the psychological factors >which can influence our perceptions is all. The problem with pure psychological factors is that there is no direction if it is .......
96: Propeller Head Plaza, Re: Hunter in the woods (0.00)
Posted by mfc on 2003-07-25, 21:07:43 (67.75.231.21)
Hi, >That works in a practical sense, but I don't see that it necessarily >establishes actual audibility seeing as all the possible >psychological factors are still present. The standards I use is: do .......
97: Propeller Head Plaza, Good idea! (0.00)
Posted by mfc on 2003-07-25, 18:21:26 (67.75.231.69)
Thanks! .......
98: Propeller Head Plaza, Re: Cap loaded (0.00)
Posted by mfc on 2003-07-25, 17:20:42 (67.75.231.96)
Hi, With a .2uF || 10 ohm load the frequency response is down .022dB at 20Khz. The .25dB point is at 45.4Khz. It rolls off pretty gracefully from there. The -3dB point (relative to 1Khz) is 112.14Khz. .......
99: Propeller Head Plaza, I like it a lot! (nt) (0.00)
Posted by mfc on 2003-07-25, 13:32:18 (67.75.230.238)
. .......
100: Propeller Head Plaza, Re: Hunter in the woods (0.00)
Posted by mfc on 2003-07-25, 13:19:31 (67.75.230.238)
Hi, >no one ever falls in love with their audio equipment? I'm not going to go there :) >how exactly do you know whether or not that perception is the result >of physics of psychology? I usually pull .......
101: Propeller Head Plaza, Re: Hunter in the woods (0.00)
Posted by mfc on 2003-07-24, 15:56:03 (67.75.230.210)
Hi Steve, >For the audiophile, music seems simply a means with which to connect >with the audio equipment and for the musicphile/music lover, the >audio equipment seems more a means to connect with th .......
102: Propeller Head Plaza, IM is the elephant... (0.00)
Posted by mfc on 2003-07-24, 00:46:24 (67.75.231.108)
...in this measurement (8v peak band limited square wave at 1050Hz composed of odd harmonics out to 27th with a 1v peak sine wave at 5Khz). The IM products from the square wave are the size of an elep .......
103: Propeller Head Plaza, Re: Cap loaded (0.00)
Posted by mfc on 2003-07-24, 00:36:32 (67.75.231.108)
Hi Scott, Thanks...I ended up with 14uH || 10 ohms for the load of .2uF and 10 ohms. Also used 2500pF of compensation cap. All this combo'd together got rid of any ringing. The -3dB point was about 11 .......
104: Propeller Head Plaza, Hi JCox (0.00)
Posted by mfc on 2003-07-23, 22:53:20 (67.75.230.147)
I was wondering when you might come around here... How's it going? Good reference. I think Spice does a good job on nonlinear capacitance, as long as the model params are well captured. .......
105: Propeller Head Plaza, Re: Cap loaded (0.00)
Posted by mfc on 2003-07-23, 15:19:39 (67.75.215.173)
Hi, Increasing the cap on the load causes the peak in frequency response to reform. With .3uF across the load, the bottom of the square wave had oscillation (lot of ringing) at 498.885Khz. The top was .......
106: Propeller Head Plaza, Re: Cap loaded (0.00)
Posted by mfc on 2003-07-23, 14:18:30 (67.75.215.173)
Hi Scott, For the compensated case, the .1uF caused the hi-frequency response to peak up a bit at 348.337Khz. Using a 1uF cap on the load caused ringing on the low points of the square wave but not th .......
107: Propeller Head Plaza, Cap loaded (0.00)
Posted by mfc on 2003-07-23, 12:28:03 (67.75.230.223)
Here are some interesting results for the MLJ3281 Sizklai follower with compensation and with a .1uF capacitor across a 10 ohm load. 3900pF capacitor inserted between collector and base of first trans .......
108: Propeller Head Plaza, Re: Compensating Sziklai doesn't help (that much) (0.00)
Posted by mfc on 2003-07-23, 00:15:01 (67.75.215.221)
>Try adding .1uF/1uF across the load I tried a few different values, .1uF, 1uF, 2uF. They all oscillated at around 326Khz. .......
109: Propeller Head Plaza, Re: Isn't Slew Rate a bit like THD? (0.00)
Posted by mfc on 2003-07-22, 23:53:20 (67.75.215.221)
Hi, >Therefore, if you have an open loop bandwidth (dominant pole) of >1MHz, then you won't have any TIM distortion below 1MHz. However, >you can have plenty of harmonic distortion that is frequency > .......
110: Propeller Head Plaza, Measurements at "Test for Transients Thread" below (nt) (0.00)
Posted by mfc on 2003-07-22, 22:38:15 (67.75.215.221)
nt .......
111: Propeller Head Plaza, Re: Isn't Slew Rate a bit like THD? (0.00)
Posted by mfc on 2003-07-22, 22:32:40 (67.75.215.221)
Hi, >Where is your dominant pole? 1.000Mhz >What about non-linear capacitance? Its being modeled. Not sure what you mean. .......
112: Propeller Head Plaza, Re: Isn't Slew Rate a bit like THD? (0.00)
Posted by mfc on 2003-07-22, 20:41:27 (67.75.231.1)
Hi, Before you slew rate limit out a stage, you can get TIM which is what I was seeing. Heh Scott, I see Cherry's 2nd paper is talking about calculating TIMD using a small sine wave and a large band-l .......
113: Propeller Head Plaza, Isn't Slew Rate a bit like THD? (0.00)
Posted by mfc on 2003-07-22, 18:19:14 (67.75.231.90)
Hi, It seems to me that calculating slew rate is a bit like calculating THD. It doesn't really show the profile of the distortion components that are being produced under dynamic conditions. This is s .......
114: Propeller Head Plaza, Single EF Results (0.00)
Posted by mfc on 2003-07-22, 18:13:40 (67.75.231.90)
Hi, Here are some results for the single MLJ3281: Square Wave = 1050 Hz. Using 1,3,5,...25,27 harmonic values only. 27th = 28350Hz. Amptitude = 8v peak. Gibbs phenomena (although present)was very smal .......
115: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-22, 17:01:29 (67.75.230.221)
Hi, I'm not familiar with how to set the step size so it relates to noise floor. You'd have to know n and X and how that relates to noise floor in order to specify n and X. I know I want a noise floor .......
116: Propeller Head Plaza, Compensating Sziklai doesn't help (that much) (0.00)
Posted by mfc on 2003-07-22, 16:07:24 (67.75.230.221)
Here are some interesting results for the MLJ3281 Sizklai follower with compensation. Square wave at 8v peak. 3900pF capacitor inserted between collector and base of first transistor. Square Wave = 10 .......
117: Propeller Head Plaza, More interesting Sziklai follower results (0.00)
Posted by mfc on 2003-07-22, 14:30:42 (67.75.231.101)
Here are some interesting results for the MLJ3281 Sizklai follower (no compensation). All I did was increase the square wave from 4v to 8v peak. Square Wave = 1050 Hz. Using 1,3,5,...25,27 harmonic va .......
118: Propeller Head Plaza, Re: Some Sziklai follower results (0.00)
Posted by mfc on 2003-07-22, 10:12:37 (67.75.230.140)
Hi Scott, >Basically everything above H3 is at -135dB (or thereabouts). That's why the 3rd column...to show that the ultimate resolution measured straight out of the signal source is -190dB! The -135d .......
119: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-22, 09:46:27 (67.75.230.140)
Hi, I'm not so sure this is the alpha state. This sounds like we enter some sort of dream state. I don't think this captures it. The state I'm thinking about more closely resembles a hunter in the woo .......
120: Propeller Head Plaza, Some Sziklai follower results (0.00)
Posted by mfc on 2003-07-21, 20:06:55 (67.75.215.235)
Here are some initial results for the MLJ3281 Sizklai follower (no compensation) : Square Wave = 1050 Hz. Using 1,3,5,...25,27 harmonic values only. 27th = 28350Hz. Amptitude = 4v peak. Gibbs phenomen .......
121: Propeller Head Plaza, Re: Some preliminary results (0.00)
Posted by mfc on 2003-07-21, 09:37:43 (67.75.230.169)
Hi Scott, Yes it is the simple emitter follower. I'll try the Sziklai tonight, and also the compensated Sziklai. .......
122: Propeller Head Plaza, Some preliminary results (0.00)
Posted by mfc on 2003-07-19, 10:19:55 (67.75.231.72)
Hi, Here are some initial results for the MLJ3281: Square Wave = 1050 Hz. Using 1,3,5,...25,27 harmonic values only. 27th = 28350Hz. Amptitude = 4v peak. Gibbs phenomena (although present)was very sma .......
123: Propeller Head Plaza, No results yet (0.00)
Posted by mfc on 2003-07-19, 01:19:19 (67.75.231.43)
Hi, This may serve as some practical guide for what can go wrong in doing simulations if nothing else... In order to get more meaningful results...I doubled the frequency of everything. This causes an .......
124: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-19, 01:07:58 (67.75.231.43)
Hi Steve, Ok I get it now. I'd say that the phenomena that you are talking about happens. I'd say it happens to me a % of the time however. I can be led astray. I've done it. What usually snaps me bac .......
125: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-18, 22:53:22 (67.75.230.206)
Hi, Yes definitely seeing Gibbs. I doubled the frequency of everything and am out to the 27th odd harmonic now. Base frequency of the square is 1050Hz and this goes on out to 28350 Hz. Frequency of th .......
126: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-18, 22:44:12 (67.75.230.206)
Hi, Let's try an example...take soundstage. That's a term I like because it is purely subjective. You can't measure a soundstage. Suppose I improve the S/N ratio of the power supply in an amp by addin .......
127: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-18, 22:17:05 (67.75.230.206)
Thanks, Scott... I was looking for an acceptable upper bound on frequency. I'll start with 30khz (or kc :) .......
128: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-18, 22:14:39 (67.75.230.206)
Hi Duke, 10-4 on the settling time. Ran into that problem before. The window is highly dependent on the frequency. I use a 1 uS step size and a window of .2 seconds. This works quite well with a 525 H .......
129: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-18, 21:22:04 (67.75.231.109)
Hi, >If you're trying to decide what sounds best to you, then I can't >think of anything but our ear/brain system >If you're trying to decide whether different audio circuits produce >actual audible d .......
130: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-18, 21:14:44 (67.75.230.150)
Hi, I have removed all leakage. Various ways this can be done. Windowing (Hamming, triangle, etc.), or the trick I use which is coherent sampling. This requires a window that provides an *integer* mul .......
131: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-18, 20:10:44 (67.75.231.27)
Hi, >In truth, you can find out just as much with a single sine wave in >this situation. Regarding the static IM test you mention above, that is what I was thinking as well. This makes it easier becau .......
132: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-18, 18:24:06 (67.75.231.66)
Hi Steve, Ahhh, I see that without labels, our ears can make the decision for us. The problem is when we try to impose our beliefs on others? But surely there is a direction we are all headed. Prior t .......
133: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-18, 14:09:48 (66.179.49.35)
Hi, Around '92 I got the State 'o the Art D/A. Lots of good reviews, etc. It sounded great to me as well. About 7 yrs later, all the reviews said "Oh, the new version is so much better. Everyone shoul .......
134: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-18, 11:21:43 (66.179.49.35)
Hi, Couple of problems to overcome have been holding this up...need a little help. First is the input waveform. There are 7 voltage sources for the 1,3,5,7,9,11,13th harmonic with amptitudes set to be .......
135: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-17, 13:29:31 (66.179.49.35)
Hi Steve, >What are you basing your assumption on? Good question. Here are some assumptions. 1) Ear/Brain is incredibly discerning, probably the greatest measurement tool there is. 2) Changes I made .......
136: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-17, 01:12:45 (67.75.231.77)
Hi, >What exactly is the "something" you're trying to explain the >physical cause of? My hypothesis is that distortion makes circuits sound bad. Eliminate distortion and the circuit sounds good. ::: T .......
137: Propeller Head Plaza, So that's where he hides it :) (0.00)
Posted by mfc on 2003-07-17, 00:41:19 (67.75.231.77)
nt .......
138: Propeller Head Plaza, Re: It's better to travel in hope .... (0.00)
Posted by mfc on 2003-07-17, 00:37:30 (67.75.231.77)
Hi again Steve, >as long as we keep taking the same approach that the "creation >science" crowd does. No, No, No...this isn't a search for data to support a forgone conclusion (if that's what your get .......
139: Propeller Head Plaza, Re: I can't see the distortion for all the harmonics ..... (0.00)
Posted by mfc on 2003-07-16, 21:43:43 (67.75.215.191)
Hi Steve, I think its ok to develop a hypothesis and then get data. Another way to do it is data mining (look at the data, form a hypothesis). There are probably a lot of things that need to be connec .......
140: Propeller Head Plaza, Re: I can't see the distortion for all the harmonics ..... (0.00)
Posted by mfc on 2003-07-16, 19:16:26 (67.75.231.57)
Hi Duke, Well, not just emitter follower linearity. More trying to get data to support why certain circuits sound better than others. Current thinking (at least mine) is to greatly limit how much 7th, .......
141: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-16, 14:29:17 (66.179.49.35)
Hi, One good thing about the test as is, the FFT itself shows only the sqrt of the products of the absolute real and imaginary parts. So it should accomodate phase shift somewhat. Also, I'm ignoring I .......
142: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-16, 01:06:35 (66.179.49.35)
Hi, A little more time now to respond... >It is my firm belief that signal distortions down to -90 dB are >relevant to what we hear when listening to a home playback event. As bad as the 7th, 11th, 13 .......
143: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-16, 00:31:49 (66.179.49.35)
Here is a list of model parameters and quick definitions for the MLJ3281 ** means measured value different from default * means specified but equal to default blank means not specified * AF Flicker .......
144: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-15, 21:10:06 (67.75.231.109)
Hi, Gotta run...but here is the model for a MJL3281 from Motorolas site. Lots of effects being modeled these days * Model generated on Jan 7, 98 * MODEL FORMAT: PSpice .MODEL Qmjl3281a npn +IS=6.5498e .......
145: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-15, 16:42:30 (67.75.230.208)
Hi, >not to get yourself into a confusing situation, where you will have >everybody and his/her brother interpreting your results in different >ways. Including my own misinterpretations of the data on .......
146: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-15, 13:27:49 (66.179.49.35)
Hi Steve, >Are you just interested in simply getting a picture of the total >distortion? Yes, but broken down by harmonic. As long as the IM is low, then I think the test will be valid. I can see anot .......
147: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-15, 13:05:48 (66.179.49.35)
Hi, >The intermods from the square wave harmonics will all fall on top of >the harmonics themselves The intermods could be seen when viewing the results from the sine wave sim tests. These would start .......
148: Propeller Head Plaza, Re: test for transients (0.00)
Posted by mfc on 2003-07-15, 12:31:44 (66.179.49.35)
Hi, >Still, the odd order harmonics will fold back on the primary signal. I can see how a real world measurement of this would be tough. For a simulator (and Excel) it should be able to sub out the id .......
149: Propeller Head Plaza, test for transients (0.00)
Posted by mfc on 2003-07-14, 22:19:25 (67.75.215.192)
Hi, Interested in looking at phase anomalies and their effect in a circuit. Want to look at the transient case where a phase anomaly can cause overshoot, ringing, etc. Want to then provide quantitativ .......
150: Propeller Head Plaza, Re: TIM (0.00)
Posted by mfc on 2003-07-14, 20:09:21 (67.75.215.237)
Hi, The effect you are talking about I'm familiar with as when someone in the audience on a recording has a creaky seat, or coughs. In a hi-res system, the brain doesn't have to work hard at all to un .......
151: Propeller Head Plaza, Re: TIM (0.00)
Posted by mfc on 2003-07-14, 18:29:09 (67.75.231.48)
Scott, Charles mentions a strong preference for simple emitter followers. These seem to have minimal disturbances in phase. One question is: What does a phase disturbance sound like? Can phase anomali .......
152: Propeller Head Plaza, Re: Darlington Distortion and Single Device Distortion Results (0.00)
Posted by mfc on 2003-07-14, 13:38:46 (66.179.49.35)
Hi, Great suggestions. I noticed when the driver starts running out of current, the bottom part of a sine wave, on the right side, just after the peak develops a flat spot. A single device emitter fol .......
153: Propeller Head Plaza, Re: TIM (0.00)
Posted by mfc on 2003-07-14, 01:22:52 (67.75.231.3)
Hi Charles, Since we've seen Kurt's great derivations today, it looks like we are dealing with one basic kind of emitter follower for all of the different types we have been discussing. However as you .......
154: Propeller Head Plaza, Darlington Distortion and Single Device Distortion Results (0.00)
Posted by mfc on 2003-07-14, 00:59:47 (67.75.231.3)
Hi, I thought I'd post these just to complete the survey of various follower types... Here were the conditions for the Darlington MJL3281: B+ = 24V, Iload = 1.3529 amps, Remitter = 10, Rload = 10 (thr .......
155: Propeller Head Plaza, Darlington AC sweep (0.00)
Posted by mfc on 2003-07-13, 20:50:27 (67.75.231.93)
Hi, Did an AC sweep on a Darlington built out of a pair of MJL3281s. It had a peak at 437Khz, although it was not nearly as pronounced as the Sziklai. Compensated with 3500pf from base to collector of .......
156: Propeller Head Plaza, Re: Emitter follower stage as a feedback amplifier, Part 2 (with corrections) (0.00)
Posted by mfc on 2003-07-13, 18:18:42 (67.75.215.224)
Hi Kurt, I think you have it right basically. Back to the books for me. Ahh, here are some terms I've been using incorrectly. Beta isn't feedback factor according to Langford-Smith. The quantity (1-BA .......
157: Propeller Head Plaza, Re: Can I correct for bad room acoustics with a new interconnect? (0.00)
Posted by mfc on 2003-07-12, 23:19:41 (67.75.230.214)
Or we could all go watch Saturday night wrestling. They do a lot of the same stuff :0) .......
158: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-12, 23:15:37 (67.75.230.214)
Exactly Steve, This is what really got me...what does "100% feedback" mean? What I think it means is: put a probe on the emitter to gnd of the Sziklai and I measure 13.05 volts peak to peak...put a pr .......
159: Propeller Head Plaza, these conclusions don't fit with the later AC analysis (0.00)
Posted by mfc on 2003-07-12, 16:14:50 (67.75.231.46)
See below .......
160: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-12, 16:11:25 (67.75.231.46)
That was an AHA! The data stares you in the face. At first I refused to believe it, and then it all clicks. Thanks John .......
161: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-12, 15:13:23 (67.75.231.27)
>base to emitter Should have typed base to collector. Fingers don't follow brain sometimes. .......
162: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-12, 14:59:41 (67.75.231.27)
Hi, Yes! FEEDBACK!!!! Putting a 3500 pf cap from base to emitter fixes it by rolling the gain off. But this is what I don't get...If we have a lot of feedback, then why are the distortion results so l .......
163: Propeller Head Plaza, original circuit results (0.00)
Posted by mfc on 2003-07-12, 14:53:58 (67.75.231.27)
Hi, Here are the results using the circuit values I got from Steve. Here was the setup for the simulations: +-12v for B+, Rload = 10, R2 = 220, R3 = 3.3, R1* (base bias) = 50K. Vin = 4v peak @ 200Hz, .......
164: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-12, 12:33:57 (67.75.231.35)
Hi John, Here is the AC sweep results on the same circuit from the previous message: F-3db(lo) = 160.1Hz F-3db(hi) = 2.704Mhz The low end has a nice looking roll off. On the hi end, there is a nasty p .......
165: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-12, 02:25:40 (67.75.231.16)
Hi, Ran some simulations on the Sziklai pair. The idea was that if it is unlike a simple emitter follower, then its distortion profile should show it. Bottom line...it is just like a simple follower. .......
166: Tube DIY Asylum, Re: Primer on Paralelled Triodes (0.00)
Posted by mfc on 2003-07-10, 19:24:20 (67.75.230.137)
Here ya go .......
167: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-10, 19:06:45 (67.75.230.137)
Hi Steve, >... the feedback is effectively 100% I've heard this applied to all Cathode followers and it gets confusing. I suppose it means that the feedback signal is roughly the same amplitude as the .......
168: Propeller Head Plaza, How about food? (0.00)
Posted by mfc on 2003-07-10, 18:50:59 (67.75.230.137)
Blueberry season just started here in Oregon. .......
169: Propeller Head Plaza, Re: 110V PSU possibilities (0.00)
Posted by mfc on 2003-07-10, 18:47:13 (67.75.230.137)
Hi Steve, >though I would have a hard time imagining that it has never been >done up until recently. I've seen a choke in a Sand amp power supply, but not in a Sand amp output stage. They were outlawe .......
170: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-10, 13:55:05 (66.179.49.35)
Hi Scott, That is a real interesting special case. I wonder if it will take care of odd order terms? This looks like something to look into. Mike .......
171: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-10, 13:43:59 (66.179.49.35)
Hi Scott, >By increasing the NFB we can reduce these to some arbitrary figure, >say, -120dB. One observation, is that for a *really* linear device, you can get hi order harmonics down, way down, to li .......
172: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-10, 13:31:37 (66.179.49.35)
Hi John and others, For multiple stages, I'm thinking of a transfer curve that isn't nearly as linear as a single stage. See link below... What I found useful in this article was its discussion about .......
173: Propeller Head Plaza, Re: I've got a dumb question.... (0.00)
Posted by mfc on 2003-07-10, 10:53:38 (66.179.49.35)
Hi Charles, Partly guilty... This simulation series on followers got started due to interest in investigating whether feedback was happening in followers and unbypassed common cathode stages. A claim .......
174: Propeller Head Plaza, Re: How about at 6V? (0.00)
Posted by mfc on 2003-07-10, 00:46:06 (67.75.231.123)
Hi Kurt, Should go to bed but this fun... Here it is for 6v bias on the gate with the current source. Source = 10 ohms + .8H Choke, Rload = 10, Vin = 2V peak, Iload = .466 amps fundamental: 0.00 2nd : .......
175: Propeller Head Plaza, or just drop bottom bias resistor to 450K (0.00)
Posted by mfc on 2003-07-09, 20:58:22 (67.75.215.237)
...to get the same effect. Depending on device. .......
176: Propeller Head Plaza, shifted operating point (0.00)
Posted by mfc on 2003-07-09, 19:35:45 (67.75.231.87)
Hi Kurt and others, Played around with the operating point in Spice a little after work. Went with a battery to ground thru a 200K resistor to gate so I could vary the bias. At Idc = .715 amps, Rload .......
177: Propeller Head Plaza, Re: Cathode follower amp update - up to 600mW of power! Woohoo! (0.00)
Posted by mfc on 2003-07-09, 00:14:54 (67.75.230.214)
Hi, >Mike, did you happen to run the test for the FET w/R load only? Not at first. So convinced was I that it would be bad. Tried running it just now. Rsource = 10 (and no choke), Coutput = 100uF, RLo .......
178: Propeller Head Plaza, Re: 110V PSU possibilities (0.00)
Posted by mfc on 2003-07-08, 22:05:54 (67.75.231.80)
The choke idea is fairly novel. I don't think I've seen it used in a CF before. .......
179: Propeller Head Plaza, Re: Cathode follower amp update - up to 600mW of power! Woohoo! (0.00)
Posted by mfc on 2003-07-08, 21:52:14 (65.58.1.167)
Hi, Indeed you are right. I ran a simulation of a 2sk1058 model. Compared the circuit shown (idealized choke) and a circuit with an idealized CCS running at the same operating point and same load. The .......
180: Propeller Head Plaza, Re: Cathode follower amp update - up to 600mW of power! Woohoo! (0.00)
Posted by mfc on 2003-07-07, 21:11:34 (67.75.215.225)
Cool Kurt. Any plans to CCS it? .......
181: Propeller Head Plaza, Re: Cable Forum Mission (0.00)
Posted by mfc on 2003-07-07, 10:38:52 (66.179.49.35)
Hi Steve, >I could never even so much as point out that a mischaracterization >had been made Yes you can point it out. The problem is that words like "lashing" and "phantom" have double effects. At th .......
182: Propeller Head Plaza, Re: Cable Forum Mission (0.00)
Posted by mfc on 2003-07-06, 22:04:44 (67.75.215.182)
Hi Steve, >...the only way it seems things will go better is for nothing to go >at all. In other words, that I never question anything... Just a comment on writing style. Statements like the above are .......
183: Propeller Head Plaza, Re: Cable Forum Mission (0.00)
Posted by mfc on 2003-07-06, 17:03:29 (67.75.230.240)
Hi, >His posts are not constantly criticized by me. I should have asked if you are a little tired of the way these interactions are going. Maybe have things go a little better? It may be that John doe .......
184: Propeller Head Plaza, Re: Cable Forum Mission (0.00)
Posted by mfc on 2003-07-06, 16:34:49 (67.75.230.240)
Hi, What I'm learning is that you both know how to set the other off. This turns into a 360 degree feedback loop with gain > 1 - and we have an oscillator. For a moment set logical thinking aside. Dea .......
185: Propeller Head Plaza, Re: Cable Forum Mission (0.00)
Posted by mfc on 2003-07-06, 09:57:17 (67.75.231.51)
Hi, John mentions that he just gets static when he posts from you. I think he gets kind of tired of posting and having it constantly criticized. Don't get upset if this isn't what you think is happeni .......
186: Propeller Head Plaza, Re: Cable Forum Mission (0.00)
Posted by mfc on 2003-07-05, 22:05:54 (67.75.231.38)
Hi, I think subjective listening is a good thing. It usually leads in ways that measurements alone would not suggest. Yet, and to its credit, subjective listening is highly repeatable. This leads me t .......
187: Propeller Head Plaza, Re: I fixed a bias problem in my Mosfet follower (experiment #1 continued) (0.00)
Posted by mfc on 2003-07-02, 22:15:08 (67.75.215.238)
Hi, >Think of it as signal-induced *changes* in group delay. OK, I get the picture now. Thanks It seems like there is a lot of rediscovering of old ideas that have been forgotten. I guess you can just .......
188: Propeller Head Plaza, Re: I fixed a bias problem in my Mosfet follower (experiment #1 continued) (0.00)
Posted by mfc on 2003-07-02, 18:34:52 (67.75.230.254)
Hi Scott, >The spectrum of phase IMD contains the same frequency components as >amplitude IMD, but their phases differ by pi/2. Ahh, very interesting. Would the amplitude of PIMD depend on the amount .......
189: Propeller Head Plaza, Re: I fixed a bias problem in my Mosfet follower (experiment #1 continued) (0.00)
Posted by mfc on 2003-07-01, 22:25:41 (67.75.215.148)
Hi Kurt, I guess I should clarify. I wasn't referring to Nyquist or Bode diagrams or any of the basics. I was more thinking about phase modulation of the signal, when the feedback deviates just slight .......
190: Tube DIY Asylum, Re: "Good" Negative Feedback (0.00)
Posted by mfc on 2003-07-01, 21:46:13 (67.75.231.103)
Hi, >Removing the cathode bypass cap increases the local stage NFB. >This reduces distortion and increases the linearity of the local >stage Depends on the amount of local feedback. Here is a link tha .......
191: Propeller Head Plaza, Re: I fixed a bias problem in my Mosfet follower (experiment #1 continued) (0.00)
Posted by mfc on 2003-07-01, 18:58:45 (67.75.230.189)
Hello, >First, it has a very low intrinsic output impedance. Yes, relative to an 8 ohm speaker load, an emitter follower built with some beefy transistors could make 8 ohms seem like a light load. Tha .......
192: Propeller Head Plaza, Re: I fixed a bias problem in my Mosfet follower (experiment #1 continued) (0.00)
Posted by mfc on 2003-07-01, 12:45:34 (66.179.49.35)
Hi Scott, I wish their was a better term for multiplication. It makes it seem like these terms (harmonics) weren't present in the first place. It looks like they are always present, they are just buri .......
193: Propeller Head Plaza, Re: I fixed a bias problem in my Mosfet follower (experiment #1 continued) (0.00)
Posted by mfc on 2003-06-30, 22:18:21 (67.75.231.32)
Hi Kurt, >Then you have a situation where Vpk and Ip are both constant with >varying Vg and Vk. This forces Vgk to be constant. In other words, >the original cathode follower never moves from its cent .......
194: Propeller Head Plaza, Re: I fixed a bias problem in my Mosfet follower (experiment #1 continued) (0.00)
Posted by mfc on 2003-06-30, 20:02:34 (67.75.230.229)
Hi, I thought I'd put these results up here since the other thread below was starting to get branch rot. The Cathode follower simulation was similiar to the Common cathode simulation done earlier. A 6 .......
195: Propeller Head Plaza, common cathode unbypassed cathode resistor results (0.00)
Posted by mfc on 2003-06-28, 23:29:33 (67.75.230.254)
Hi, Here are the results for a common cathode stage with simple cathode degeneration. I'm working on the cathode follower... I used a 6c45 Spice model with a battery and resistor in the cathode. To in .......
196: Propeller Head Plaza, side question on feedback (0.00)
Posted by mfc on 2003-06-26, 21:38:48 (67.75.230.201)
Hi, >This threshold is set not only by feedback factor but also by >inherent linearity (neglecting DIMD's). If the triode is inherently >linear then PRF might make it moreso, is what I'm saying. Here .......
197: Propeller Head Plaza, Re: Care to elaborate? (0.00)
Posted by mfc on 2003-06-26, 20:57:39 (67.75.230.201)
>In a transformer, the impedances are reflected based on the square >of the turns ratio. In a bipolar Sziklai pair, the impedances are >reflected based on the product of the betas of the two devices. .......
198: Propeller Head Plaza, Re: I still think so... (0.00)
Posted by mfc on 2003-06-26, 18:23:54 (67.75.230.216)
I'm still in :) Here is a good link showing how closely related a follower is to NFB. http://digilander.libero.it/paeng/design_frame.htm click on cathode follower The output signal in the follower .......
199: Propeller Head Plaza, Care to elaborate? (0.00)
Posted by mfc on 2003-06-26, 08:28:27 (67.75.230.254)
Are you talking about the primary and secondary? .......
200: Propeller Head Plaza, Re: Don't think so (0.00)
Posted by mfc on 2003-06-25, 21:26:27 (67.75.215.132)
Hi, >But it does not apply to followers. This is why I said that it is >misleading to refer to followers as having "feedback". Cathode resistor sees output current. Causes voltage drop proportional to .......
201: Propeller Head Plaza, Feedback (0.00)
Posted by mfc on 2003-06-25, 18:47:24 (67.75.230.224)
Hi, >"feedback" clearly implies that the signal is being "fed" from one >point in the circuit "back" to a point earlier in the circuit. This >does not happen with a follower (or when using an unbypass .......
202: Propeller Head Plaza, Thanks (nt) (0.00)
Posted by mfc on 2003-06-17, 18:11:41 (67.75.215.189)
. .......
203: Propeller Head Plaza, Re: What is linear distortion? Thanks (nt) (0.00)
Posted by mfc on 2003-06-17, 08:20:31 (67.75.230.221)
Hi, Just trying to get my head around the implications of linear distortion... DA is a phenomena where the distortion pattern doesn't change with increasing signal amplitude (to reasonable levels), an .......
204: Propeller Head Plaza, What is linear distortion? Thanks (nt) (0.00)
Posted by mfc on 2003-06-16, 18:46:02 (67.75.230.199)
. .......
205: Propeller Head Plaza, Re: Happy meal all week (0.00)
Posted by mfc on 2003-06-12, 18:01:40 (67.75.215.242)
Hi, "To keep that number over 20Hz to 20kHz band you need the noise density of about 140 times less per root Hz, or about .3nV" Can you show your math? I've always wanted to know how to use those root .......
206: Propeller Head Plaza, Re: Try this on for size! (0.00)
Posted by mfc on 2003-06-06, 21:43:16 (67.75.230.193)
Hi, You sound like you have heard significant differences by moving speaker toe-in a fraction of an inch. I have. I feel that image size is being affected. I find it interesting that we have no quanti .......
207: Tube DIY Asylum, Re: p.s. (0.00)
Posted by mfc on 2003-06-01, 17:46:23 (67.75.215.232)
Hi, Since the TL-431 is just used as a voltage source, and is driven by a current source, it can be replaced with a resistor and capacitor. The resistor is calc'd by knowing the voltage drop divided b .......
208: Propeller Head Plaza, Re: Cheever's Fundamental Misconception (0.00)
Posted by mfc on 2003-05-22, 19:10:27 (67.75.230.156)
Hi Scott, The nice thing about using the property of an even harmonic to "neutralize" an odd harmonic, means that the Null condition can be attained solely by using the local properties of frequencies .......
209: Propeller Head Plaza, Extended harmonics - look at Self (0.00)
Posted by mfc on 2003-05-19, 00:59:11 (67.75.230.192)
Hi, With all that feedback, I was curious what my weighted THD measure would produce using D. Self's distortion results. This weighted THD measure is based on: sqrt( W2*W2*N2*N2 + W3*W3*N3*N3 + ...) w .......
210: Propeller Head Plaza, Re: Another way to calculate THD (0.00)
Posted by mfc on 2003-05-18, 22:13:44 (67.75.215.237)
Hi again, Ran an experiment where all harmonics where set to the same value of .001 (-60db) of the fundamental. Simulating a flat distortion pattern like you get from SS. THD calculated = .35% Using p .......
211: Propeller Head Plaza, Re: Another way to calculate THD (0.00)
Posted by mfc on 2003-05-18, 21:05:49 (67.75.215.230)
Hi, I made a spreadsheet of all the harmonics that shows what note they produce, what relationship it is (ie. fifth, major 3rd, etc), and how out of tune it is with the well tempered scale. Anybody th .......
212: Propeller Head Plaza, Re: Cheever's Fundamental Misconception (0.00)
Posted by mfc on 2003-05-17, 18:38:29 (67.75.230.214)
I should have said masking of an odd harmonic by an even harmonic not masking of an even harmonic by an odd harmonic. .......
213: Propeller Head Plaza, Re: Cheever's Fundamental Misconception (0.00)
Posted by mfc on 2003-05-17, 18:05:32 (67.75.230.221)
"Both Cheever and Hiraga insist on achieving an accurrate fit both as to ratio and to rate of fall-off for each harmonic." Yes but here in: http://www.audioasylum.com/forums/prophead/messages/2967.htm .......
214: Tube DIY Asylum, Re: DN2540 stock (0.00)
Posted by mfc on 2003-05-17, 11:58:17 (67.75.230.217)
I bought 30 from them several months ago. They have a minimum *online* order of $50. Don't know about a phone order. .......
215: Propeller Head Plaza, Re: Cheever's Thesis Half Right (0.00)
Posted by mfc on 2003-05-17, 10:40:26 (67.75.230.217)
Hi Scott, Great article. Couple of comments. "Mfc thinks that when feedback reduces all high-order products below the level of the open-loop circuit, that particular amplifier will sound better *with* .......
216: Propeller Head Plaza, Re: Another way to calculate THD - close (0.00)
Posted by mfc on 2003-05-15, 22:46:33 (67.75.231.72)
The equation has a flaw. If a pair of harmonics is sticking way up, and they are in the right proportions, the equation could give a value of 0 which isn't correct. .......
217: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-15, 20:54:08 (67.75.230.132)
Thanks for hanging out in this forum. I appreciate the opportunity to chat with people like you and Scott. Please see this link below. The depth of this thread was starting to get me dizzy trying to f .......
218: Propeller Head Plaza, Another way to calculate THD (0.00)
Posted by mfc on 2003-05-15, 20:45:14 (67.75.231.69)
In looking thru Cheever's calculations, we see a couple of problems: 1) In the limit when distortion approaches 0, TAD seems to give erroneous results. 2) Weighting of all harmonics are judged the sa .......
219: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-14, 21:18:56 (67.75.215.197)
Hi, Cheever's equation must break down for harmonics like the 8th (3 octaves), the 10th (3 octaves + major 3rd), and the 12th (3 octave + 5th). These harmonics are very consonant and also very much in .......
220: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-14, 19:53:56 (67.75.231.100)
Hi, An example of what you mean by "it should be noted that musical chords IM in tune with the other notes." I'm not following you. The reason you lost me is because IM is a beat frequency with a stri .......
221: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-13, 19:44:34 (67.75.231.71)
Hi, I've kind of dismissed Hiraga on feedback, I agree with you, his points about thresholds are very worthwhile however. An AHA for me lately has been this. Accept that certain distortion patterns ar .......
222: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-12, 21:45:10 (67.75.223.223)
Sorry, I don't think I have it. My second explanation isn't right either. Hiraga shows this complex tone going thru the test amp and then he looks at the output. It looks like the setup needs to be as .......
223: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-12, 21:30:27 (67.75.223.223)
Hi again, Now, I think I see what Hiraga was saying... I think the point about his complex waveform generator is that, he could simulate an entire amplifier with feedback, and he did this by setting u .......
224: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-12, 21:21:54 (67.75.223.223)
Hi, Oh. I didn't read this carefully enough. Hiraga isn't talking about a single pure sinewave, he is talking about a complex waveform compose of pure seperately contollable parts. I'm glad you caught .......
225: Propeller Head Plaza, Re: From Pianos to Amps (0.00)
Posted by mfc on 2003-05-12, 21:02:30 (67.30.87.84)
Hi, I received the book from Amazon. That is one of the first "physics of music" type books worth getting...and its less than $10 :) They even had subjectivist/objectivist debates back then. Page 181 .......
226: Tube DIY Asylum, Re: Gary Pimm Current Sources (0.00)
Posted by mfc on 2003-05-11, 20:28:58 (67.75.231.48)
Here are the numbers for a 6c45 and a (2x) DN2540 FETs cascoded current source. The current source was something we discussed on this forum a few weeks ago. The numbers are basically identical to the .......
227: Tube DIY Asylum, Gary Pimm Current Sources (0.00)
Posted by mfc on 2003-05-11, 17:35:48 (67.75.230.147)
Hi, I've been listening to an amp I've built based around a variation of Gary's current source. The amps sound amazing. I built a simulation of the driver stage in Spice to see what sort of theoretica .......
228: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-11, 14:27:02 (67.75.230.242)
Hi, I should clarify the previous message. We want to use devices that have a harmonic pattern that falls off more rapidly than what the Cheever data or the Hiraga data would indicate is neccessary. T .......
229: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-11, 10:34:55 (67.75.230.242)
Hi, I don't really think I've ever found any written material that has explored these particular intricacies of feedback. I've learned a lot about feedback since this thread started. Let me give my ex .......
230: Propeller Head Plaza, Bypass the cathode resistor (or not) (0.00)
Posted by mfc on 2003-05-10, 21:31:03 (67.75.230.129)
Hi, This was part of a subthread down below discussing whether or not to bypass a cathode resistor because it changes the harmonics. It was an interesting question posed by John Curl ( I always read h .......
231: Propeller Head Plaza, Re: Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-10, 20:36:31 (67.75.230.129)
OK. I'll ignore Hiraga. I studied the data from both somewhat... Took the data from Hiraga and the data from Cheevers graphs. They do two different things. If you take a look at the delta between harm .......
232: Propeller Head Plaza, Hiraga on Feedback (0.00)
Posted by mfc on 2003-05-10, 17:10:13 (67.75.230.217)
Hi Scott, One thing that has me confused is that Hiraga talks about feedback like small amounts *reduce* higher order distortion. We have seen in this thread that small amounts of feedback *increase* .......
233: Propeller Head Plaza, From Pianos to Amps (0.00)
Posted by mfc on 2003-05-09, 19:59:42 (67.75.231.60)
Hi John, I can almost hear several violin or piano makers discussing this subject 2 or 3 centuries ago. Not that they would be talking about feedback, but they would have terms for 2nd, 3rds, overtone .......
234: Propeller Head Plaza, Re: Harmonic Multiplication in Linear Devices (0.00)
Posted by mfc on 2003-05-09, 10:48:34 (67.75.230.183)
Hello, OK, got it. But then one advantage of feedback isn't really an advantage (reduces distortion), cause it really is doing a good job on the 2nd, but not the other harmonics. To get *real* reducti .......
235: Propeller Head Plaza, Ordered it from Amazon, and Test setup (0.00)
Posted by mfc on 2003-05-09, 10:39:40 (67.75.230.183)
Hi, I'm thinking of using a 16-bit Soundcard, some sort of differential preamp to null out the crud, and software like Audiotester to investigate these low level harmonics. Can you see things like cap .......
236: Propeller Head Plaza, Re: That's what I was thinking.... (0.00)
Posted by mfc on 2003-05-09, 02:37:41 (67.75.231.23)
Hi Scott, Cheever didn't have much data on the 45. I'll look around for a 45 model though. I tried the TY55N20 (which is really a MTY55N20) since Cheever shows data for this. Also figured out how to g .......
237: Propeller Head Plaza, Re: That's what I was thinking.... (0.00)
Posted by mfc on 2003-05-08, 19:45:13 (67.75.231.12)
Hi, I'd like to see a device that has no high order harmonics, and then apply feedback and watch the harmonic multiplication occur. I think I'll see if I can find a decent model for Cheevers example t .......
238: Propeller Head Plaza, Re: The paper can't be that good and here's why... (0.00)
Posted by mfc on 2003-05-08, 19:37:13 (67.75.231.12)
Hi Steve, "Only that it's rather silly to relate them to the music scale itself." ... "Particularly given that the western, even-tempered scale you're relating them to isn't universal." This particula .......
239: Propeller Head Plaza, Re: That's what I was thinking.... (0.00)
Posted by mfc on 2003-05-08, 13:22:36 (65.212.157.20)
k. I'll try it to night (this isn't my day job unfortunately). My Spice shows harmonics up to 1Khz. The frequency I'm using is 50Hz. So that would show the first 20. I hope I didn't obscure the fact t .......
240: Propeller Head Plaza, Re: That's what I was thinking.... (0.00)
Posted by mfc on 2003-05-08, 00:47:16 (67.75.231.63)
Hi, I spent a little time with Spice this evening. Used a DN2540 FET model in a local feedback circuit. Wanted to see if varying level of local feedback increased high order harmonics. I veried feedba .......
241: Propeller Head Plaza, Oh, not spices, more like rat poison? Not really (0.00)
Posted by mfc on 2003-05-07, 16:13:15 (65.212.157.20)
That is a real cool reference... On a different note :), I know a clarinet produces some odd harmonics. But these must be balanced, and allow the instrument to produce its beautiful piercing sound. An .......
242: Propeller Head Plaza, Re: The paper can't be that good and here's why... (0.00)
Posted by mfc on 2003-05-07, 00:39:08 (67.75.231.100)
Silly? Don't think so. Not if your amp produces a lot of 7th, 11th, 13th harmonic. The point is the input source material contains harmonics and fundamentals. The brain locks all these together and pr .......
243: Propeller Head Plaza, Re: Neither pentodes nor transistors (0.00)
Posted by mfc on 2003-05-06, 19:34:55 (67.75.215.155)
Hi, Here is something I've wondered about and you probably know. If you take two triodes in cascode, you essentially create the plate characteristics of a pentode. Wouldn't this type of stage have muc .......
244: Propeller Head Plaza, Re: That's what I was thinking.... (0.00)
Posted by mfc on 2003-05-06, 19:23:53 (67.75.215.155)
Hi, How about local feedback? A resistor from plate to grid, or an unbypassed cathode resistor? Even a triode has feedback builtin. AFAIK, a pentode doesn't have any feedback (although it can be kind .......
245: Tube DIY Asylum, Re: Some reasons why high order harmonics are bad (0.00)
Posted by mfc on 2003-05-06, 15:58:49 (65.212.157.20)
Yes, I agree about the harmonics already present in the source material. Those already present in the source compose a recipe of sorts. This recipe is a composition consisting of a blend of basic ingr .......
246: Tube DIY Asylum, Some reasons why high order harmonics are bad (0.00)
Posted by mfc on 2003-05-05, 18:19:21 (67.75.215.250)
Out of tune and some harmonics are dissonant. More at the link. .......
247: Tube DIY Asylum, Re: Since I started this............ (0.00)
Posted by mfc on 2003-05-05, 00:35:36 (67.75.231.83)
"4) our ear/brain processing systems find small amounts of high order distortion discordant." Yeah, I've been busy building a spreadsheet that looks at high order harmonics compared to their correspon .......
248: Propeller Head Plaza, Re: The paper can't be that good and here's why... (0.00)
Posted by mfc on 2003-05-04, 21:19:35 (67.75.230.170)
Hi, In the process of looking at how harmonics match notes I stumbled on another big misconception I had. The 5th harmonic does *not* correspond to a major 5th in an octave. The 4th harmonic does *not .......
249: Propeller Head Plaza, Re: The paper can't be that good and here's why... (0.00)
Posted by mfc on 2003-05-04, 19:44:49 (67.75.230.170)
Here are some interesting fun facts about the differences between harmonics and notes. Looking at the 7th harmonic... Take all 12 notes starting at C1 (32.703 Hz) up to C2 (65.406 Hz). Multiply the no .......
250: Propeller Head Plaza, Re: OK, all you hi-RPM propellerheads........... (0.00)
Posted by mfc on 2003-05-04, 16:24:32 (67.75.230.170)
Hi Scott, Yes I suppose that is probably what these pioneers were doing. It never occurred to me until very recently that a common thread to these approaches is the idealized triode plate characterist .......
251: Propeller Head Plaza, Re: The paper can't be that good and here's why... (0.00)
Posted by mfc on 2003-05-04, 10:24:17 (67.75.231.17)
Looked around and found some interesting (to me anyway) graphs showing how (some) harmonics of a note will differ slightly from the notes on a standard piano. Before I assumed that the problems were t .......
252: Propeller Head Plaza, Re: The paper can't be that good and here's why... (0.00)
Posted by mfc on 2003-05-03, 21:37:28 (67.75.231.18)
"...higher order odd harmonics because they do not follow the musical scale very well" Are you saying (for example) the 9th harmonic of 100hz (900Hz) doesn't match a note? If this is so, it all makes .......
253: Propeller Head Plaza, Re: OK, all you hi-RPM propellerheads........... (0.00)
Posted by mfc on 2003-05-03, 17:48:58 (67.75.215.187)
An ideal triode would have plate characteristics with equally spaced grid lines (constant grid voltage plotted on a graph of plate voltage -vs- plate current would be equidistant from each other). Eac .......
254: Propeller Head Plaza, Re: OK, all you hi-RPM propellerheads........... (0.00)
Posted by mfc on 2003-05-03, 14:40:32 (67.75.230.143)
Scott, The article you mention in stereophile (your the author :) along with the Hiraga article have to be the two best articles on amp design I've ever read. What do you think is the best way to appr .......
255: Propeller Head Plaza, Re: The paper can't be that good and here's why... (0.00)
Posted by mfc on 2003-05-02, 15:48:05 (65.212.157.20)
Hiraga states in his paper that eliminating the high order harmonics makes for a dull or soft sounding amp. I think this paper also implies that high order harmonics must be smoothly decreasing, becau .......
256: Propeller Head Plaza, Re: OK, all you hi-RPM propellerheads........... (0.00)
Posted by mfc on 2003-05-02, 00:44:19 (67.75.215.192)
His figure 2-2 in his paper is the one he gets all his data and derives his calculations from. It is not in the book referenced in his paper: Olsen, Harry F. “Music, Physics and Engineering .......
257: Propeller Head Plaza, Re: Neon Bulbs as Bypass Capacitors (0.00)
Posted by mfc on 2003-04-30, 19:48:21 (67.30.83.137)
It was across the AC mains, and barely illuminated. You caused me to remember an effect I'd forgotten about that had a very positive improvement in my system. I got a chuckle when I remembered doing t .......
258: Propeller Head Plaza, Re: Neon Bulbs as Bypass Capacitors (0.00)
Posted by mfc on 2003-04-30, 18:05:41 (65.58.155.15)
Hi, I was really surprised to by your post... I've tried various power conditioners and didn't like them. Finally settled on an old power strip with a neon bulb in it. Several years ago, I decided the .......
259: Hi-Rez Highway, Re: Does anybody know if Theta Digital is working on a SACD player or universal player? (0.00)
Posted by mfc on 2003-04-03, 18:29:58 (65.58.223.153)
They just released a Gen 8 D/A at CES. Don't know when it will ship. I asked them about SACD, and they said they were prepared for it, but I got the understanding that this would be an upgrade to the .......
260: Tube DIY Asylum, Re: DN2540 MOSFET (0.00)
Posted by mfc on 2003-03-20, 22:06:54 (67.30.85.182)
Try www.allamerican.com They have a minimum online order of $50. .......
261: Tube DIY Asylum, Re: Perfectly balanced still cancels even order harmonics? (0.00)
Posted by mfc on 2003-03-18, 01:00:44 (65.58.157.75)
I think you have it. Here is my interpretation... It looks like the feedback summing node is the output transformer which is interesting. Push Pull operation would cancel or reduce even harmonics. It .......
262: Tube DIY Asylum, another thought (0.00)
Posted by mfc on 2003-03-18, 00:04:00 (65.58.157.75)
Heh Gary, How about an arrangement with a pentode driver driving a grounded grid triode output stage? The pentode should see the Rp of the output tube divided by its gain or Rp/A. This should be down .......
263: Tube DIY Asylum, Re: Single FET CCS (0.00)
Posted by mfc on 2003-03-17, 23:30:06 (65.58.157.75)
Slightly smaller lots can be bought from: www.allamerican.com They have a minimum online order of $50 + shipping. I got 30 DN2540s at that price. They are amazing devices. .......
264: Tube DIY Asylum, Perfectly balanced still cancels even order harmonics? (0.00)
Posted by mfc on 2003-03-16, 09:35:28 (65.58.156.22)
When you talk about a simple harmonic spectrum do you mean total absence of even harmonics but still a few odd harmonics? .......
265: Tube DIY Asylum, Re: Shouldn't that be 2.9v on the cathode? nt (0.00)
Posted by mfc on 2003-03-15, 00:28:32 (65.58.152.66)
Hi, Yeah I got trigger happy on my first send. But what is the extra drop of 7v for? In other words 2.3v/45ma only needs 51 ohms. Why the 220? .......
266: Tube DIY Asylum, Re: Shouldn't that be 2.9v on the cathode? nt (0.00)
Posted by mfc on 2003-03-14, 21:17:27 (67.30.86.74)
Just noticed the drop between cathode and grid is probably 2.9v, but the 9.9 is between cathode and gnd. What does the extra 7v drop thru the bottom of the bias pot help? .......
267: Tube DIY Asylum, Shouldn't that be 2.9v on the cathode? nt (0.00)
Posted by mfc on 2003-03-14, 20:58:38 (65.58.1.193)
nt .......
268: Propeller Head Plaza, Re: looking for book (0.00)
Posted by mfc on 2003-03-09, 18:25:41 (65.58.153.121)
No Joy. A search on author R. D. Patterson just turns up books on sexual preferences :-) .......
269: Propeller Head Plaza, looking for book (0.00)
Posted by mfc on 2003-03-09, 09:17:51 (65.58.7.157)
Hi, I was wondering if anyone knew the original audio textbook this image came from? I think it was from the '60s and might be something by R. D. Patterson. I've been looking around for it on the Inte .......
270: Tube DIY Asylum, Looks like cathode feedback to me (0.00)
Posted by mfc on 2003-03-05, 19:31:23 (65.58.7.29)
Here's a link .......
271: Propeller Head Plaza, Re: Critical Bandwidths.... (0.00)
Posted by mfc on 2003-02-25, 18:02:15 (65.58.6.54)
Hi jj, >Well, the number of critical bandwidths or ERB's between the >fundamental and a given harmonic determines about how much the >fundamental will mask the harmonic. This sounds interesting. What .......
272: Propeller Head Plaza, Re: That only holds for a very small slice of the frequency spectrum... (0.00)
Posted by mfc on 2003-02-23, 09:53:21 (65.58.159.12)
Hi, During my diggings, I found a graph (originally by Wegel and Lane) that shows how the distortion pattern varies with frequency and level for the first 5 harmonics. It appears in Harry F Olson. M .......
273: Propeller Head Plaza, Re: Confusion (0.00)
Posted by mfc on 2003-02-22, 22:23:10 (65.58.5.222)
Hi, That is why I used the example of the quarter note in the previous message. An individual cycle has an attack and decay, but a note itself has an attack and decay that lasts many cycles. A notes a .......
274: Propeller Head Plaza, Re: Harmonic patterns (0.00)
Posted by mfc on 2003-02-22, 12:59:02 (65.58.223.92)
Hi, Perfect. Just what I was looking for. This seems to be on the right track. Thanks! .......
275: Propeller Head Plaza, Re: Harmonic patterns - Timbre and music - to humans (0.00)
Posted by mfc on 2003-02-22, 11:41:17 (65.58.223.92)
Hi, Good. Now I know exactly what you are referring to as an attack. I think Fourier covers what you call an attack under the umbrella of fundamental plus overtones. Look at this link below and you ca .......
276: Propeller Head Plaza, Re: Harmonic patterns - Timbre and music - to humans (0.00)
Posted by mfc on 2003-02-21, 20:42:43 (65.58.223.121)
Hi, >since the metal resonates easier, I expect some loss and hence >it'll take slightly longer for the attack. My purpose for diving further into the experiment was to understand what you and Timbo a .......
277: Propeller Head Plaza, Re: Harmonic patterns - Timbre and music - to humans (0.00)
Posted by mfc on 2003-02-21, 18:36:10 (65.58.2.219)
Hi, >This is almost certain as attacks very accurately characterise >each instrument's structure and resonances, no matter what the pitch. You say this as a fact. I don't know that it is. >This is so .......
278: Propeller Head Plaza, Re: Harmonic patterns - Timbre and music - to humans (0.00)
Posted by mfc on 2003-02-20, 19:30:27 (65.58.222.205)
Hi, Thanks for the food for thought. Do you have any research on the subject of attacks and decays you can point me at? I wouldn't dismiss harmonics + overtones (harmonic patterns?). Here is an exampl .......
279: Propeller Head Plaza, Re: Can you please explain to a layman why Wadia Digimaster ... (0.00)
Posted by mfc on 2003-02-16, 08:43:21 (65.58.7.34)
Its filter has gentler slopes than a brick wall filter. This allows the filter to not ring as much when a impulse type of signal comes along. The gentler slopes start rolling off earlier in the audio .......
280: Propeller Head Plaza, Harmonic patterns (0.00)
Posted by mfc on 2003-02-16, 00:32:57 (65.58.153.16)
Hi, What a cool place! Has anyone seen anything interesting about harmonic masking or patterns of distortion? I know there are the usual rules of thumb about lo-order distortion being preferrable to h .......
Found total of 280 records, Query: , Author: mfc in All Forums, Time: 1 sec.