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RE: Since you still have a burr under your saddle

"Wait- huh? All people that listen to Naim amps can't hear worth a damn?"

Pretty much yes...same for 99% of the rest of hifi gear that sounds like crap.

Most people are not good critical listeners and the latch on to either advertisement (Naim is good at PRAT) or some specific aspect of the sound they like at the expense of most of the rest.

"The amps you are talking about are not designed for class B. You seem to be ignoring that simple fact. So yes, when improperly biased (and so operating as a class B amp) they will have a problem. But if the circuit is designed to get around that problem with intention of being a class B circuit then your statement is false."

Designed to get around it HOW??? You keep saying that but it doesn't mean that there is a way around it. Naim certainly hasn't found the way around it because they make Class B amps that have zero crossing distortion. If you know how to get around it then demonstrate how you would get around it. The fact that you haven't expressed a single circuit idea on how to do it tells me that YOU DON'T KNOW HOW to do it. Oh, and please provide measurements that demonstrate that it actually worked as claimed...claims aren't what they used to be you know.

User feedback is meaningless. You can always find someone who likes something, no matter how terrible it really is. It is evidence of nothing other than a subjective opinion and you don't know if that is in the minority or majority. You see the difference??

"'ve worked with amps that were operating class B because of insufficient bias and I can tell you they don't reproduce a sine wave properly. You don't need to have them at super low power- the problem shows up because at zero crossing the amp is low power at that point! Amirim's measurements don't show any evidence of a problem; if there was one the sine waves he showed would have been sufficient. Based on your comments though I fear this will be lost on you."

It's sad that you think a professional challenge is abusive. Stop being a snowflake Ralph and man up. You keep ignoring my point that Amir's measurements don't show the residual distortion in the sine wave plot. With low distortion amps the high level sine wave will never look distorted, you have to extract out the residual distortion and plot it like Stereophile does (so, we know it's possible but curiously Amir doesn't do it) and then you can see if there is zero crossing distortion. Until then there is no proof one way or the other. The fact that STereophile gets this and you don't seem to get it makes me wonder what you have really learned in 40 years of amp designing. Measurements don't seem to be your strong suit.

https://www.stereophile.com/content/naim-classic-200-series-nap-250-power-amplifier-measurements

Please refer to Figure 7 to illustrate what I am referring to. You see the residual distortion plot shows the zero crossing distortion in this Naim amp. No such plot was provided for the Topping.

"You've still not explained how the EV A-20C, which is a class B amp, can have no zero crossing artifact."

Explain what? You have not provided any evidence that this is in fact true. I cannot explain something that has not be demonstrated to exist. When you can do that, then perhaps there is something to discuss here.

"My recommendation is get an amp on which you can adjust the bias and put a scope on it, then adjust the bias and see what I'm talking about. If there's a problem at the zero crossing its pretty audible and you won't need a super low signal level to see in on the 'scope."

I have first-hand experience with a Plinius SA-103, which has a Class AB and Class A bias setting (push of a button on the front panel). The sound quality difference is very significant and the measurements on Stereophile show clearly the effect of the AB setting vs. the A setting.

https://www.stereophile.com/content/plinius-audio-sa-103-power-amplifier-measurements



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