tube amplifier auto bias- accurate?

Bin, please see my comments above, which is my opinion of Eldartford being "one of the most knowledgeable here on tube amps".

I'd rather have auto bias. I don't have the time or the patience to do it any other way. I have an amp that I turn on and play music, end of story.

A question on auto bias. When would an amp perform said biasing? Unless it was a real smart implementation, seemingly auto biasing would be active all the time the amp is on, that is even when music is being played. Wouldn't that have a negative impact on the music?

Tubes108...In military equipment that I worked on we had a similar situation.... we were adjusting amplitude and phase of an AC power supply to account for variables of the load. The way to do it is to run the adjustment process until the parameter you are adjusting is within some tolerance, (and then a little longer so you don't always get hung up ON that tolerance). Then, quit the adjustment process unless the parameter drifts outside of a larger tolerance. In other words, introduce "hysteresis".

This is how automatic tube bias adjustment onbviously ought to be done, but...? Does anyone know the actual details?

This is an excerpt from Hank Wolcott in response to questions about how his amplifier works:

The circuit has to be made virtually distortionless through optimal loading before positive feedback can be allowed to increase the gain.

The output of the pentode cathode follower is direct coupled to the output stage and constant current sourced by a pair of transistors forming a current mirror.

The grid circuit of the output tubes is connected to a digitally controlled automatic bias circuit which checks and resets individual tube biases at turn-on and then is disengaged from the signal path

I don't know if that helps, I know Hank very well and could call him and ask for more details.