Krell anticipator circuits of the 1990s

@johnlnyc    Thank you for this input.

As in my OP, the anticipator circuit is claimed to monitor the output from the pre-amp and adjust the bias quickly enough so that the change has taken effect before that output is amplified.  A tall order I think.

At the introduction of the FPB series environmental issues were discussed.  My KRS200s draw more than 1kW per side.

Just because an idea is patented doesn't mean it is effective.

As a manufacturer previously claiming the benefits of pure Class A, if they wished to sell FPB prorduct it was encumbent on Krell to claim they had overcome the disadvantages of Class AB designs.

Yes the circuit could be proven on the bench but it has not been.  The time that the circuit takes to adjust the bias has never been revealed or found.  To that extent it is a secret circuit.

The paper you publish does not speak of the time it takes to change the bias.

I never said it was claimed the circuit could tell the future.  It does claim it can change the bias quickly enough in response to changes in the signal.  We don't know if that claim is true or not.

Krell has never been forthcoming with any of their circuit designs and schematics. They also came out with sustained plateau bias long before the FPB series came out.

@invalid    I am aware of these facts.

Not so long.   I believe the first variable bias Krell was the KSA300S, launched in 1994.  The first of the FPB series started in 1997.

The krell audio standard was the first variable bias amplifier krell made, it was their flagship amplifier at the time 1993 I believe.

Thanks, right.  It was 35,000 1993 dollars.  KRS200s were around $30,000 in the late 80s, so very much on a par.

Looking around the used ads I find KRS200s are regularly priced around double the 1990s FPBs.  I wonder if this is related to sound quality?