Krell anticipator circuits of the 1990s

So the Bias slides up, big deal and down. Krell would have done time domain tests to determine if there spurs appear off the fundamental.  Something like this would not be done by a field but an engineer. We would do this in the digitally domain for the floating dynamic amps and  converters we built. It not simple but not rocket science either but timing has to perfect as did this to 60 channels in parallel. This was at Texas Instruments and several others. I doubt I changed any minds but keep an open mind that analog computing is fast.

I’m in on Pass Labs, Cherrs

@jaytor 

Do you use your parallel  300b amplifier and Pass Labs XA 60.8 driving the same pair of speakers? Is so, this seems an interesting comparison of two very different topologies. Nice!

Charles

Maybe Martin Collums in his Stereophile review, gets it.

“Krell's regulation feature is still more impressive when you take into account Krell's "Sustained Plateau Biasing," a patented Krell technique that provides an effective equivalent to class-A biasing—without a long-term power dissipation penalty—by anticipating the size of any and every musical event (footnote 1). It uses high-speed current-feedback circuitry to do this, then holds these required levels in a static condition for tens of seconds after the event is over. This minimizes any possible dynamic interaction of bias level with sound quality. The FPB 600's seven stages of bias represents the highest evolution yet of this technique…”

@johnlnyc 

Martin Collums doesn't add anything to the debate.  He eulogises the anticipator circuit.  But he doesn't say how long it takes for the bias to be changed.  That still hides behind the emperor's new clothes.

At this point it is necessary for me to repeat the question in my OP: how long does it take for the amp to react to the increased current generated by the signal (the big bass drum hit) before the bias is restored to Class A.

No-one has told me.  But it will be longer than it takes for the initial pulse of that drum hit to pass.

The bias is always in class A unless you exceed a certain temperature, then the top two bias levels stay in class A/B until the temperature drops.