Krell anticipator circuits of the 1990s

@yyzsantabarbara   Yes I did watch the video.  This adds nothing to the story.  The Krell personnel say the Class A watts output is varied according to monitoring of the watts of the signal output.  It does not say how it is done - 'we've found a way...', 'a very high degree...'., 'this is completely new...'.  All this is marketing puff.  It does not say how long the amp takes to adjust the bias in response to the measured output.

Since Krell must know the length of the delay, we are left to assume it must be relatively long.  If it were so short that there is an argument that its effect is inaudible, Krell would surely have told us the details.  This is all very unsatisfactory and in the result I continue to use my KRS200s.

If that guy does not spill the beans, then I doubt anyone else will since I am under the belief that he was the inventor of the iBias circuit.

Indeed.  If they don't tell us the details then we can be pretty sure it's a pig in a poke.

It may even be the iBias circuit is a spoof.  If there is anything good to tell then they will tell it.  They are protected by patents, after all.

If it sounds impossible then it probably is impossible.

It's interesting that the subject of my initial post:1990s anticipator circuits, continues into new Krell products being launched right now, nearly 30 years later.  Brought my subject right up to date.  Maybe they're still selling the same old tat.

Not at all like Krell's first product, the KSA50 which was and remains wonderful.  I still use the one I bought nearly 40 years ago, in my second system.  Not even a service required, although use has been sparse these 30 year.

I still don't believe it.

+1@jasonbourne52,

Qualified Krell service engineers have not been able to explain to me how it can work.

In my opinion they could not explain how it works because they knew it was marketing baloney.

Example of marking baloney in audio see below:

This feature plateau biasing circuit allows for the Krell FPB 600 amplifier to have Class A bias output without all the wasted electricity and heat. Really?

This is all very unsatisfactory and in the result I continue to use my KRS200s.

I agree, keep the Krell KRS200s if want new ''real'' class A amps see Pass XS300 mono block amps, they will give you all the heat you need to keep your English castle warm. 😎

Mike

https://www.passlabs.com/product_tags/class-a/

@dlcockrum - My friends amplifier is a Krell KSA-100S.  It has sustained plateau biasing with four lights on the front to indicate the various levels.  Not quite the same implementation, but similar concept.