Correct Sheldon.
The Original Poster was doing a " Shishido Loftin White", which we know has none of the " original-design's " hum cancellation. Essentially, a simple two-stage direct-coupled all-triode amp,..... with a high mu Driver stage,, and 2A3 Finals.
Jeff
The Original Poster was doing a " Shishido Loftin White", which we know has none of the " original-design's " hum cancellation. Essentially, a simple two-stage direct-coupled all-triode amp,..... with a high mu Driver stage,, and 2A3 Finals.
Jeff
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Why don't you just get the compilations from me, read them over, and decide for yourself IF it is worthy of your time, to build and listen to? Decide AFTER reading what the two EEs say.
Never mind, that this supply sounded GREAT at the RMAF show this year !! 🙂
Jeff
Well, I already read the JLH post you referenced above. Frankly, it made no sense. If what you are saying is true, it really shouldn't be hard to explain why in simple language. Instead, I am seeing fuzzy terms like "dynamic contrasting." Is that the same as dynamic range or something? I just don't even know what it is that you are claiming with that term, hence the snark above (sorry, by the way).
Personally, my latest designs used Maida-style regulators and I couldn't be happier with the power-supply performance. They have no output capacitor (well, besides the Zobel) so I guess I adopt your philosophy in a way. However, if I were building a conventional power supply I would want considerably larger capacitors than what you are advocating.
BTW, your appeal to the authority of the others being EEs probably doesn't carry that much weight in a forum filled with EEs. Facts (and being able to articulate them) are what matter.
Hello,
I really THINK I understand where you are coming from.
Contact me please, and allow me to send you the two EE's 2008-2010 compilations. I am TERRIBLE at explaining things, and these two guys are NOT. BUT, one must read the posts as a WHOLE. It should be helpful. Free. drlowmu@gmail.com
Jeff
I really THINK I understand where you are coming from.
Contact me please, and allow me to send you the two EE's 2008-2010 compilations. I am TERRIBLE at explaining things, and these two guys are NOT. BUT, one must read the posts as a WHOLE. It should be helpful. Free. drlowmu@gmail.com
Jeff
I've shown up to where I agree with you. Whether more final capacitance is harmful, remains.
The supply first stage is going to have series resistance for damping the transformer, can be dealing with higher frequency undesirables and lots of ripple, all unrelated to the audio goal including the topology, and choice of components. Would you blame me for not wanting this first stage in the signal path?
A low shunt impedance can put up a two way barrier anywhere along the supply. (An example is a smoothing cap filling in the missing 0V portions of ripple, this cap essentially becomes the supply).
SET users listen to a modulated power supply. In most cases, as I explained, they also listen to a modulating power supply. Both effects are present, but much weaker, in a conventional P-P amp with feedback. Hence it is particularly important that SET has a good supply, which means caps of adequate size - somewhat larger than would be needed for a more conventional amp. Get this wrong and you may hear it, although you may prefer it to be wrong.drlowmu said:
Could I get some clarification on the former please. Is this where the rail isn't sitting still so that the character of the supply can be brought into the mix?
No, that would be the latter. All I was saying is that drlowmu is right to say that SET people listen to the supply but modulated by the output valve (better designs such as PP don't suffer from this problem to the same extent); hence SET needs a good supply with big enough caps. What he seems not to realise is that SET people also listen to the supply modulating the output (and input) valves.
I am amused by the frequent references to EEs, as though this guarantees the truth of their statements. Of course, some non-EEs can talk more nonsense about electronics than EEs but at least non-EEs have an excuse. Anyway, I don't take much notice of person A saying that B supports him, as my experience is that sometimes B has been misunderstood by A. I once queried a derivation given by an EE professor in a lecture; instead of answering my point he referred me to the textbook; on checking I found that the textbook agreed with me. It was a subtle point he had got wrong, so I concluded that the point had gone over his head.
I am amused by the frequent references to EEs, as though this guarantees the truth of their statements. Of course, some non-EEs can talk more nonsense about electronics than EEs but at least non-EEs have an excuse. Anyway, I don't take much notice of person A saying that B supports him, as my experience is that sometimes B has been misunderstood by A. I once queried a derivation given by an EE professor in a lecture; instead of answering my point he referred me to the textbook; on checking I found that the textbook agreed with me. It was a subtle point he had got wrong, so I concluded that the point had gone over his head.
Fair enough. I think this should be able to go without saying, in an ideal world. I build SET amps, I don't like distortion and I don't like stages talking to each other through the supply. I used to be different, I haven't ceased building SETs but I've changed the way I do it.
AllenB,
Have you requested and READ the compilations as I have asked people to do? If not, I suggest you start there !! Especially if you build SETs !!
I am sure DF96 will NOT request and read the compilations, simply given his general nature. This is quite OK for me.
The material will help you, I am sure of this, from decades of me DIY building DHT amps ... since 1982.
Jeff
Bingo !
These ill-fated LSES (or "flywheel") creatures seem to be liked by very few people of age far beyond 60, probably its some kind of mental nostalgia of their grand-mom TV sound era.
One can search AudioAsylum for enormous amount of this junk science presented as "brilliant engineering gem", promoted by someone without even basic knowledge of electronics.
Attachments
I can't get to my email at the moment. If you can post the file or provide a link, I'll read it.
Hi AllenB,
When you can get to your email, send me one and I will happily send you the compilations by return email.
Regards,
Jeff
I guess refutation of what has been said takes more effort than merely objecting to the fact that it has been said. The former leads to a technical discussion; the latter leads nowhere.
SE vs PP
Unfortunately most valve amplifiers do have an output transformer, here is the great advantage for SE, in a SE OPT current flows always in the same direction, the magnetic field vector, B, always conserve the same direction also, this subtle fact has enormous importance because it needs less energy to orientate magnetic domains inside transformer core, i.e. less losses/more linearity and minimize Barkhausen noise due to lower movability of magnetic domains.
In addition, a SE OPT has an air gap in its core, which lowers magnetic permeability to an extent that it is quite constant all over the hysteresis loop, this ensure linearity.
Some people call this "micro detail" and "quack experts" make fun on them.
Unfortunately most valve amplifiers do have an output transformer, here is the great advantage for SE, in a SE OPT current flows always in the same direction, the magnetic field vector, B, always conserve the same direction also, this subtle fact has enormous importance because it needs less energy to orientate magnetic domains inside transformer core, i.e. less losses/more linearity and minimize Barkhausen noise due to lower movability of magnetic domains.
In addition, a SE OPT has an air gap in its core, which lowers magnetic permeability to an extent that it is quite constant all over the hysteresis loop, this ensure linearity.
Some people call this "micro detail" and "quack experts" make fun on them.
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Very interesting comments to me. Enjoyed what you wrote a whole lot.
From my simple, common sense perspective, HOW can someone expect to perfectly INVERT the phase in a P-P amp, and TRY to perfectly recombine it at the output, with NO LOSSES or degradation??
Would be much better to leave the signal alone, and intact.
ONE other IMPORTANT thing, you can not use a B+ of 409 VDC , leading to the Finals, to do a Loftin White Type 2A3 amplifier. B+ needs to be in the vicinity of 485 VDC, give or take ten VDC, to optimize the two audio tubes' op points. 409 VDC as a start, as shown the the very beginning of this thread, assures mediocre load lines / op points !! This is one of several areas where Nobukazu Shishido and Isamu Asano's early L-W style amps are deficient. Another is their use of an R/C filter after the tube rectifier. That is a huge error, both those fellows adding series resistances, as it needs to become L/C there. L1/C1/L2/C2 always works and sounds best to the Finals.
Jeff
From my simple, common sense perspective, HOW can someone expect to perfectly INVERT the phase in a P-P amp, and TRY to perfectly recombine it at the output, with NO LOSSES or degradation??
Would be much better to leave the signal alone, and intact.
ONE other IMPORTANT thing, you can not use a B+ of 409 VDC , leading to the Finals, to do a Loftin White Type 2A3 amplifier. B+ needs to be in the vicinity of 485 VDC, give or take ten VDC, to optimize the two audio tubes' op points. 409 VDC as a start, as shown the the very beginning of this thread, assures mediocre load lines / op points !! This is one of several areas where Nobukazu Shishido and Isamu Asano's early L-W style amps are deficient. Another is their use of an R/C filter after the tube rectifier. That is a huge error, both those fellows adding series resistances, as it needs to become L/C there. L1/C1/L2/C2 always works and sounds best to the Finals.
Jeff
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My pleasure, thank you.
Common sense sometimes agree with physical facts, Barkhausen effect reach its maximum at zero crossing, then your guess is correct, it is impossible to reconstruct a clean signal with no losses or degradation, you just can see how horrific is magnetic permeability in a whole hysteresis loop of PP OPT, they need very high primary inductance to save some quality.
Totally agree, if you want a good PP amp, forget the OPT, try a hybrid instead.
No core no pain... 😛😀
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I have to totally disagree dear Juan. The worst thing about tubes is microphony and vibrations. In real world the best hybrid combination is solid state fron-end with power tubes, IME. Barkhausen, phase splitting are highly negligible in comparison.
How do people tame (eliminate is too much for this higly ignored issue) vibrations? In the best case they use dampers that unfortunately don't work! They don't work because a damper has to damp something otherwise is useless. But if some vibration is damped it meams it has happened and altered the original signal to some extent per some time. So at low levels it is worse, first because of the worse ratio between signal and microphony. Then the distorted signal will also be amplified a lot. In general damping is widely used in audio gear but it is not good!
SS state has other issues....
How do people tame (eliminate is too much for this higly ignored issue) vibrations? In the best case they use dampers that unfortunately don't work! They don't work because a damper has to damp something otherwise is useless. But if some vibration is damped it meams it has happened and altered the original signal to some extent per some time. So at low levels it is worse, first because of the worse ratio between signal and microphony. Then the distorted signal will also be amplified a lot. In general damping is widely used in audio gear but it is not good!
SS state has other issues....
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