Krell anticipator circuits of the 1990s

@retiredfarmer     Thanks for your understanding and kind words.  I agree with all you say.

I do take Stereophile (not AS as I have been a John Atkinson fan for the whole of his journalistic career) and am keen to keep up with all the new products.  But like with my cars I don't change equipment very often and very rarely sell anything.  Now approaching my mid-70s I am increasingly finding new products, especially cars, are not to my liking and that I get more pleasure and satisfaction with the older stuff I already have.

Neither am I much of a tweaker.  I use stock mains cable and have had my heavy Kimber speaker cables 20+ years and all Kimber silver interconnects for longer than that.  I am sure someone will tell me they oxidised years ago but the music still sounds great to me.

Perhaps one should not generalise about blue collar people, but one thing most of them do not do is love their work; maybe it's not that kind of work.  I loved my work and got as much out of it is from my down time.  Spending most of the time working it is crucial that it is found enjoyable.

Yes I love Da Vinci and Monet but also Dali, although I can't do the really modern stuff.

If anyone is interested. I re-read the thread I posted earlier about 

WestminsterLab

They also have an iBias system similar to the KRELL XD. The designer of those amps explained how the iBias predicts the needed power. His amps go into Class AB for a second if they go beyond the existing limit of Class A. Then the Class A ramps up.

@yyzsantabarbara  - yes, I think that @clearthinker is misunderstanding the purpose of this type of circuit. It is not designed to anticipate the bias requirements to always be in class A. It is designed to adjust it's bias based on the user's load requirements so that it operates in class A "almost" all the time. 

I think most of us don't always listen to extremely dynamic music or at very high volumes all the time. For me, most of the time I am only needing a few watts of power from my amps. The plateau bias mechanism allows the amp to operate much more efficiently when high power is not needed, but has plenty of power reserves when it is. Once the bias has been ratcheted up, it will stay in high bias as long as the requirements persist (unless the heatsinks get too hot). 

@jaytor The type of iBias described by the WestministerLab designer seems to me different than what KRELL seems to be saying with the new iBias XD amps. I am under the impression that the new KRELL stays in Class A all the time. I was going to email Walter Schofield at KRELL and talk about the iBias but then I saw that he is no longer with KRELL.

All I know is that I put back my KRELL 175XD into my office system this morning and it sounds great. So smooth and yet powerful.

@yyzsantabarbara - I was thinking about the bias mechanism used in the older FPB series which is what I used to own. There newer amps could use something completely different.