Not hurt, just mildly disappointed (though unsurprised) that your audibility claim that supposedly had "scientific" evidence seems to be totally unsupported.
So, is there any actual data showing audible differences in CFA amps?
Even if there is one measurable difference between amplifiers, there is a basis for different sound, SY. A scientific basis. In case you want to doubt the sound difference, YOU have to organize a scientific test and bring the proof 
. As you can see, your way of arguing may be easily turned against you.
. As you can see, your way of arguing may be easily turned against you.
In case you want to doubt the sound difference, YOU have to organize a scientific test and bring the proof
BS. YOU claim the difference in sound, YOU proof that it actually exists.
If you get that far, we may indulge in trying to find out where the difference comes from. First things first.
Jan
Only if they were kept totally separate from one another and all other society.
Of course, the argument has been made that the totally random nature of "high end" amplifier design (by which I mean amplifier design that is informed by factors beyond standard engineering and generally accepted auditory thresholds) is an indication that indeed, once the basic and trivial engineering issues are addressed (e.g., low noise, flat frequency response...), all boxes of gain are indistinguishable by ears only. "Topological Analysis of Consumer Audio Electronics: Another Approach to Show that Modern Audio Electronics are Acoustically Transparent", Rich, David and Aczel, Peter, 99 AES Convention, 1995, Print #4053.
Humans love forming tribes.
Hard to believe that with some of the more advanced designers, or at least smart people who do understand the implementation of both cfa and vfa topologies that we don't have actual measured responses of these two type of amplifiers. From what I have read it is possible to make two very similar, almost exactly the same amplifiers with only the feedback circuit changed. This is where I would like to see actual measurements of not only FR but also any phase shifts and IM and other distortion products.
Perhaps this isn't enough to answer all the questions but at least we would have baseline analysis. Someone with an Audio Precision or similar equipment that could do this type of testing would be very welcome if they could give us some real information besides the anecdotal information that listening tests alone are not acceptable here as scientific proofs.
I think it is Ostripper who has done much with designs but I am not sure that any of that is beyond just sims at this point. Two real devices that can be compared at that level would go a long way to at least showing measurable comparison. Anyone capable of doing this for all of us?
Perhaps this isn't enough to answer all the questions but at least we would have baseline analysis. Someone with an Audio Precision or similar equipment that could do this type of testing would be very welcome if they could give us some real information besides the anecdotal information that listening tests alone are not acceptable here as scientific proofs.
I think it is Ostripper who has done much with designs but I am not sure that any of that is beyond just sims at this point. Two real devices that can be compared at that level would go a long way to at least showing measurable comparison. Anyone capable of doing this for all of us?
Jay,
While it is well known the higher 2nd order harmonics are what attract many to tube amplifiers why would you think that a cfa would be similar to that? Is there any evidence that a cfa would have any higher harmonic distortion than a vfa amplifier of similar topology? Now if one had higher odd order harmonics that would go a long way to answering why people would prefer one amp over the other at least as regards what we are usually calling listener fatigue, at least that is something I am wondering about.
While it is well known the higher 2nd order harmonics are what attract many to tube amplifiers why would you think that a cfa would be similar to that? Is there any evidence that a cfa would have any higher harmonic distortion than a vfa amplifier of similar topology? Now if one had higher odd order harmonics that would go a long way to answering why people would prefer one amp over the other at least as regards what we are usually calling listener fatigue, at least that is something I am wondering about.
Pretty simple, really. That which is better, is the one in a system context which provides more convincing sound. Not "nicer", not "ruthlessly revealing" - but the one that just gets 'out of the way', doesn't remind you constantly of its presence - it allows you to forget that there is a mechanical process taking place, which is attempting to recreate a musical event ... you "are allowed" to be in a place where that event is just happening, and that's all that matters at that moment ...
That's a system context, where not only topology (CFA or VFA) is responsible with sound quality.
I like CFA more than VFA but it doesn't mean that CFA is better. Earlier in the CFA thread I suggest/challenge to build a CFA version of Greg's SKA gb150d for comparison. There's good reason there.
No, I don't mean similar in term of second order distortion like that. When I say "not an easier load for the source" it means the distortion comes from the source. But of course many CFA have high input impedance but I think that is strange.
About THD, I think only recently I have seen low number from CFA, but the added complexity is not so favorable either. But this extra low number has little or nothing to do with tonality.
That's correct, Jay. Even extremely low harmonic distortion does not assure same sound and has not much in common with resulting sound. Also, added 2nd harmonic does not mean any "attractiveness" of the sound. 2nd harmonic can be easily added by software and one can easily evaluate the "attractiveness".
But I think you cannot deny that too many people are attracted to it. I think it is normal because it has the capability to mask a boring and clinical sound. Only a few people who have heard low distortion system that is even more enjoyable than fake sweet sound of second order distortion. But only a few, so. (May be there will be less debate about importance of this distortion if they understand the situation).
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