My words ;-)
Anyway, John said: "slight change" with the BQP. Sometimes in a good way and sometimes a bad one.
This is enough for me: I will never buy for 400 $ a mysterious device, that look and smell like snake oil, described with the same sentenses than the ones used on books about close encounters of the third kind, which are supposed to make a *slight* change in a good or bad direction . ;-)
Richard, nobody commented this extraordinary test result. The same amp with new better layout PCB.
Damir
They are hung up on trivia again
yes... better pcb layout and lower distortion.
THx-RNMarsh
I think this PCB version is not ready for listening test, but Richard could tell more about previous version sound.
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I'm sure its not, but the results Richard published were hardly anything to go 'wow' over. I wait for those.
Attachments
No. What I mean is a crossover nonlinearity of output impedance of class B/AB amplifier. It is not discussed here in cycles, it is not a "popular" theme. As attached and then measured at several frequencies. A "hint" for "pros" here.
It is neither a textbook, nor datasheet method and info.
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The silence that follows Mozard is still from Mozart.
And this with an evil current feedback ?
Hats off, dadod.
What kind of "nonlinearity" do you expect from an amp able to produce 0.00024% of distortion at 100W 1kHz (100W 10KHz 4Ohms = .0057%) under load ?
BTW, what are the dumping factor and slew-rate (with no input filter nor output L) ?
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That´s the problem with such tests, bias and prior belief. We all know that no perfect experiment exists but if we choose to accept or neglect possible variable because the results of an experiment suit our prior beliefs there is high risk of observing a selffullfilling prophecy.
As said before, the "unnormally" high proportion of "no difference/preference" votes raised my concern, as it is known from several studies/experiments (see for example the afore mentioned crosscultural study) that in preference tests proportion of "wrong answers" in the case of evaluating identical stimuli is usually in the range from 65-80% .
AS you´ve said already, the impact of words or prior belief might be strong and without additional controls it is impossible to conclude about the results of "sceptical" participants. It is a good countermeasure to hide the effect under tests in these cases. Would not prevent participants from exspecting something (seems that humans always do exspect something) but would minimize the impact of prior belief.
In your case it revealed "little to nothing" but we can´t really conclude about the reason due to the methodological points we have mentioned. "minute" or "no effect" might be true, but ....
The point is that the manufacturers of these devices advertise a black and white difference. No amount of bias would account for not hearing changes on the level of the claims they make.
I don't see why we should give them any benefit of the doubt. The burden of the proof is on them. Discussing ad infinitum about how subtle the changes might maybe, on a good day, with the proper system, with the good listeners be audible is just a way of giving them a credibility they don't deserve.
I don't see why we should give them any benefit of the doubt. The burden of the proof is on them. Discussing ad infinitum about how subtle the changes might maybe, on a good day, with the proper system, with the good listeners be audible is just a way of giving them a credibility they don't deserve.
Having not seen that "night and day difference claim" myself i nevertheless understand your point.
But, imo there is no widely accepted definition for "night and day" or "big difference" nor is it a given that a difference below that level can´t be or relevance (at least to some listeners).
Testing for "night and day" difference (assuming my definition) is totally different from testing trying to catch every difference. But, if you have tested for "night and day" you can´t claim having found that "no difference" or "only minute difference" possibly exist.
It´s absolutely valid point of view to express that one does not follow their "technical" explanations, does not belief in any possible audible difference and would only accept hard facts from scientific experiments.
But otoh we know (see our recent mention/discussion of inattentional blindness/deafness) that even quite large differences can slip through due to confounders.
Furthermore i hope that people do realize that there is a lot to consider which hopefully helps them when doing some tests for evaluation purposes.
Just because every consumer has to decide if something is of relevance; even if a manufacturer provides hard facts, does it mean that it is of importance to every listener? Does anybody has to buy "blind" (scr) due to the fact that somebody was somewhere, somehow able to detect a difference?
Thanks Pavel.
This is the remaining part of your #98030 post (from which I selectively quoted ) about which I would like to ask you a simple schematic of the test setup, so I can understand what the plots really show and hopefully to replicate it, I am not a pro.
The last attachment of post #98052 show an amplifier with Rout=0.035 Ohm, yes?
George
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