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

It depends on multiple elements in the design.

The Bias point the amp runs at at idle. The speed of the output stage ( slew rate ) How long long do you hold the amp stage at a class A bias before returning to idle. There are multiple way to increase the bias but end the end it must be summed to the output to the bias circuit.  We use to design analog amps for or Seismic equipment for exploration. One method is to monitor or sample the signal, it will take have multiple stages of opamps is series then compare it to a the decision point then sum the decision to the bias to increase it current and voltage p. Of the speed of the gain decision must be quick. The purpose of was the  digital control of gain was to keep the ADC at 3/4 full scale. That is the point that an ADC is most linear. This works great as we would ranging the gain of 64 channels at a time.  I have always found to keep it simple it the best approach. I have left off details because to in theory become complex. But it should work fine if was implemented to meet the change in bias in the correct time domain.  Straight class A is is more simple of course.  I always thought my Krell KSA250 was a little harsh they must have improved but it did not have dynamic biasing.

If it changed the bias in few milliseconds you will not know the difference. However can the power demand keep up, will it compress the dynamics in the outputs. The main reason for doing this is to save money in the power supply and lowering the weight and size of the chassis.
 

Example,  If a fiber is Cut on a long haul fiber network happen the system will switch to a backup fiber with in 50msec . ( telecom voice and data ) it has been proven that at most you will hear tick in that time period of 50msec to restore the path. The data is buffered and request a retransmission and it works.

In the long run you’ve added unneeded complexity to a simple amplifier to reduce cost those element I mentioned. Keep it simple stupid is the cry. But it can work, I never compared one type amp to another 🤷‍♂️