@clearthinker there is something to be said about owning your amps for many years. First off you know them very well. Secondly you are off the rat race to continually buy and sell. In my opinion it takes a bunch of time to get a system at its peak. That is not in a month or two. That takes a few years. You can get them fairly close in a few months but top performance takes time and effort and listening. As you eluded to before many times the biggest effort is put into early products. When the person who formed the company was in control and had the passion for what he was making long before the bean counters were there. As far as time goes most everyone who plays with stereo equipment at this level works very hard in what ever they do. Most blue collar people think that the wealthy are lazy that is far from the truth more like some of the hardest working people out there. So that also brings up a couple of points spare time is limited so what does a person get there happiness from in audio, listening to music or discovering each new piece that comes out? None of those things are bad but a person wants to get enjoyment out of the hobby and that in a nut shell is what the goal is. I always maintain that what a person is doing is trying to paint a picture with your hifi system. There is no right artist just different styles just because a person's taste is a monet doesn't mean a DaVinci is bad. I love hearing other people s choices as it is a view into that person's soul it shows in ways that people rarely show you. What makes me enjoy this thread is the passion that many people are showing that is one thing that is wonderful about this quest is it brings out passion.
Krell anticipator circuits of the 1990s
"Krell FPB-600 Stereo Power Amplifier
This big power amp features the evolution of the plateau biasing circuit introduced in the KSA series of amps. This circuit anticipates the power demands of the output by monitoring the incoming signal as the demand for power increases, the more power the amplifier supplies. After a grace period of fifteen seconds and no additional high current signal demands, the Krell FPB-600 amplifier returns to its appropriate power setting. This feature allows for Class A bias output without all the wasted electricity and heat."
Do you believe the anticipator can up the bias quickly enough? A guy hits a huge bass drum, the anticipator circuit senses this and ups the bias in time for the hit to be amplified in Class A?
We are talking a micro second. Once he hit it the start of the moment was over. This was a con. Created by Krell because they were under pressure from the emerging green lobby to cut power consumption. Qualified Krell service engineers have not been able to explain to me how it can work.
Me? I still have my KRS200s. Pure Class A. So there's my answer.
- ...
- 63 posts total
@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 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.
|
- 63 posts total