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Re: If your amplifier is clipping, you have left the realm of High Fidelity.

"It has long been known that clipping at low frequencies is much harder to hear than high frequencies"

So what? Most of us would be concerned with the high frequency garbage coming out since it IS much more audible. Why even bring this up??

"Your obsession with negative feedback is duly noted, however, audio amps are judged by what they do in linear mode, not when they are clipping"

Maybe that's how amps are judged but the topic is about clipping is it not? Try to stay on subject, I know its hard for you when you have nothing meaningful to say but try anyway.

And how are most high feedback amps judged in terms of sound quality when operating in the "linear" mode? At what frequencies? As I have shown with measurements, many high feedback amps show a marked increase in distortion as a function of frequency. Clearly they get much less linear at higher frequencies. Also, what do the harmonics of that distortion look like? THat is more important anyway. Do you think this gets better when the amp clips? More likely it follows the tendency and makes even MORE high frequency high harmonics when it clips.

When all amps clip there is for sure a whole spectrum of high order and high level distortion products. This is clear and in severe cases clearly audible. What I want to know is with a high level burst that pushes an amp into clipping how quickly does that amp return to normal operation once the transient has passed? Can you tell me this for your amp? How many microseconds? Milliseconds? Seconds???? Does your amp have a little wobble (ie. does it oscillate a bit?)? How does this compare among amp circuits?

IMO, most pop/rock listeners will not clip their 100 watt amps. You and I both know that this genre of music is so compressed that a few watts will be plenty loud with most speakers. YET, most amps still sound different from each other. So clearly distortion is not below audible thresholds or even at the limits of hearing.

For non-compressed acoustic music the average levels will be much lower than the compressed rock music and therefore the demand for power will usually be much less than for the rock (so we are talking quite low powers here). The PEAKS will likely drive many amps to clip (I saw a demo that showed up to 2000 watts on a music peak where average was below 1 watt) so it is not a question of if but when.

For example you have a 45 watt tube amp and 300 watt SS amp. Now for most of the music the demand at a reasonable listening level is between 0.1 and 10 watts but peaks go to 500 watts. Both amps clip but only on the same peaks, at all other times they are both operating in "linear" mode. The question then becomes: Is the clipping audible from both amps? If so, which one sounds worse at clipping? The big 300 watt amp will hard clip, being driven about 3db over its limits, how fast will it recover? The 45 watt amp will also hard clip, being driven about 10db over its limits, how fast will it recover? I am speculating that the 45 watt amp, having no feedback, will recover more quickly. Why? Because if the SS amp has high amounts feedback then a substantial clipped signal is fed back to the input and may make the amp continue to clip (or oscillate) long after the transient is gone. Can you prove to me one way or the other is correct? This has been noted by other designers so it is not like it should be something new to you.

Honestly, you are so biased in favor of your own technology that you can't even think about the problem logically. You just try to bash me which simply shows me you don't know because you never tested your amp for clipping recovery, did you? Your amp will for sure clip on some peaks because it is not all that powerful, am I right?



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