How would you compare it to another amp, unless it has the same exact circuit design one with the anticipator circuit and one without.
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.
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@invalid You used the term 'sounds better'. We are comparing different amplifiers all the time and expressing opinions as to which sounds better (to the listener). None of these has the same circuit design, yet we express opinions, sometimes vehemently. By the way, what makes you sure the circuit is fast enough?? |
Where’d this “anticipator circuit” come from? As I see it, Krell has been attempting to improve their amplifiers by innovation which includes removing/addressing issues with class A amplification while maintaining the benefits. Heat, and efficiency being the problems with fully class A. I doubt Krell is just tossing about ad claims to sell product. They are not a mass market company looking to move amps and ramp up production. I do not, I am no engineer, think the OP bass drum analogy accurately describes what Krell is doing here. It is a sort of straw man. The process is patented. It can be proven on the bench and to the ears. It either delivers its goal or it does not. It is not as some seem to think, a secret circuit that can tell the future. In the end does it deliver on its promise? |
@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. |
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