I'll make an attempt. Let's consider a class-AB amplifier.
The output stage runs in class-AB. It can distort both on large signals (like beta droop) and on small signals due to the gain discontinuity at crossover.
Everything else runs in class A. These circuits are incapable of generating discontinuities. Unless the input stage is badly designed and creates lots of TIM, which is easy to avoid. Thus, all these stages will only distort on large signals.
From GedLeee distortion metric, we learn that large signal distortions matter very little, while discontinuities in the transfer function around zero matter a lot.
The only place this can happen is at the ouput. Its large, slow transistors also usually determine open loop response, ULGF, phase margin, and therefore the amount of feedback available to correct their own distortions.
You've could have asked: "What's a knowledge engineer"
Why did you add "..when it's at home?"
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You are not alone. Never heard a convincing explanation for this. My dac has an output stage dissipating close to 50W, so there is not even a remote chance that a preamp is reducing the loading. Actually in the current setup it is not: my power amps have 100k input impedance and the preamp just 15k....
Subtle RF filtering perhaps? In any case the preamp is the most musically important part of my system. I easily find commercial power amps and speakers i can live with, not such luck with preamps, at least not up to sane price levels (~10k)
As for the power amps...not sure what exactly you mean by "front end". Are you saying you are looking at amps which only differ by the number of output devices and the ps? This may be true for the old Thresholds but the Krells generally followed very different topologies even within the KSA range...
It turns out "sustaining evidence" was made up. Such action erodes away your credibility.
It depends on what we're looking for in a discussion. Are we looking for answers or not? If we're looking for an answer, have we got the answer to our questions? I myself am not looking for any answer 😉
That was Stereophile's employees. Two questions: (1) Are they qualified listeners? (2) Is there any 'political' interest in the Carver-Stereophile agenda such that independent and serious conclusion can be expected?
I know only the answer for the first question: They are not. This is exactly what I said "What is the point saying that amp A is better than amp B if we cannot differentiate them in a blind test?"
The biggest difference comes from its frequency response. When they are made similar, the audible difference drops considerably. But it doesn't mean that everyone cannot hear more.
The first school requires (great) electronics knowledge, the second school requires (great) ears 🙂
Back to the topic and to support your claim regarding front-end importance...
GIGO, Garbage In Garbage Out. The front-end should be able to provide a perfect signal for the later stages. In low performance systems, where the bottleneck is in the output stages and everything else, the front-end doesn't matter much. But when the overall system performance is very good, you will start to hear the front-end differences! At this level, you cannot just throw in a 2N5401/2N5551 or similar transistors.
Native English speakers will understand.RobertS61 said:
My understanding (after Googling) is that a knowledge engineer is responsible for coding other peoples' knowledge into an AI system. This may be the source of the OP's confusion; he is used to handling knowledge at arm's length without fully grasping it. Hence he can form incorrect deductions which he finds personally convincing. Of course, a good knowledge engineer should always submit to the domain experts.
Correct, that's the right definition.
My knowledgedomain was in the field of environmental law and inheritance law not electronics. You're the knowledge experts I'm the interogator and that's why I posed a assumption that was not that ill based, and you can correct what I've assumed. That doesn't need to go with dedain or disrespect, just stick to your wellinformed opinions and I will adjust my "knowledge system" accordingly.
A number of us have tried to correct your wrong thinking, in various different ways, yet you still persist in it. You have not 'interrogated' us; you have stated a belief and seemed surprised to get so much adverse comment on it. A good knowledge engineer in this situation would accept that he is wrong, even if his domain knowledge was insufficient for him to understand why he is wrong.RobertS61 said:
When you are interrogating someone and that person says he has sustaining evidence, then you ask him to cite it and he says "it's in the discussion we had earlier in my opinion", you take him seriously, right?
That reading a thread about a mainboard makes it seem like it is the most important part of an amplifier may simply be a consequence of the focusing illusion: https://www.edge.org/response-detail/11984 In short: “Nothing in life is as important as you think it is, while you are thinking about it”
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