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Luxman/Accuphase/Yamaha - Quality?

It is, but people claim "it is because it is a class A amplifier" and then the discussion starts because it isn't. IMO (including what I'm writing) if someone writes things that are technically wrong, the claim has to be corrected because otherwise the wrong information is repeated and manifest and that can't be the goal. Hifi still is and always will be technical based.


 
[URL='https://sound-au.com/class-a.htm']Rod Elliot has this to say:

Another version of the Class-A amp looks exactly the same as a standard Class-AB (Class-B) power amp, except the quiescent current is increased to just over 1/2 of the peak speaker current. This is thought by some that this is not a 'real' Class-A amplifier. It is real Class-A, and is best described as push-pull (as opposed to single ended) operation. If the bias current is not high enough for the actual reactive speaker load (not some quoted nominal resistive load), it is still possible that one transistor or the other will switch off at some part of the signal cycle. This will happen at a much higher power level than is normally the case, but if this happens, then the amplifier ceases to be true Class-A.

In simple terms, if the output devices are biased to conduct the full 360 degree input cycle at any given power output/load, then it is class A. This is the very definition of class A operation. It matters nowt if it reverts to class AB at higher levels.[/URL]
 
It really doesn't matter you know. I do wonder how, if it's deliberately deceitful, Accuphase get away advertising my E-650 as "Pure Class A operation (30 watts into 8 ohms)". I've no way of knowing if the amp strays into Class AB operation, but I suspect, given my speakers and the volume I use, that it never does. so for practical purposes, it's Class A.
 
Always the same, if people like you have no arguments left, they trying to offend the other side or getting personal.:rolleyes:
I'm not arguing with you, I see zero point in you harping on about Class A cos you know best and wanna be a keyboard warrior.

If it sounds good I buy it, if it sounds crap I send it back or sell it - Meerkat
 
It is, but people claim "it is because it is a class A amplifier" and then the discussion starts because it isn't. IMO (including what I'm writing) if someone writes things that are technically wrong, the claim has to be corrected because otherwise the wrong information is repeated and manifest and that can't be the goal. Hifi still is and always will be technical based.
Yes, I just don’t see the fuss around whether it is class a or not. Personally think ‘class a’ is wasteful & unnecessary, ducks for cover etc.
 
No way a 62lbs. stereo integrated amp is 30w Class A. What is pure Class A is a 25w 65lbs. mono Mark Levinson amplifier.

There are many variants of class A from single ended (least efficient) to class G or sliding bias etc (more efficient).
Weight is not that well correlated with class A power, especially if the amp is fan cooled.


Of course weight and cost correlates well to sound quality:D:D
 
It really doesn't matter you know. I do wonder how, if it's deliberately deceitful, Accuphase get away advertising my E-650 as "Pure Class A operation (30 watts into 8 ohms)". I've no way of knowing if the amp strays into Class AB operation, but I suspect, given my speakers and the volume I use, that it never does. so for practical purposes, it's Class A.
I heard the Accuphase 100W Class A monoblocs (A-250s) in action a couple of weeks ago. They have the entertaining feature of an instantaneous digital readout of the power output, refreshed every second or so (it gets a bit hypnotizing). We played the entire Bernstein Mass VERY loud into a pair of (91dB) Fyne Audio F1-8s. For the most part the display showed an output <<5 Watts, rising to barely more than 30 Watts in the most dynamic peaks. I think the highest I saw was still <40 Watts.

What this suggests to me is that if you have a Class A amp which will deliver a solid 30 Watts in Class A, but reverts to Class AB for headroom above this, there are probably very few occasions when such an amp will depart from Class A into Class AB, unless you have inefficient loudspeakers or are trying to fill a large room to ear-bleeding levels.
 
I heard the Accuphase 100W Class A monoblocs (A-250s) in action a couple of weeks ago. They have the entertaining feature of an instantaneous digital readout of the power output, refreshed every second or so (it gets a bit hypnotizing). We played the entire Bernstein Mass VERY loud into a pair of (91dB) Fyne Audio F1-8s. For the most part the display showed an output <<5 Watts, rising to barely more than 30 Watts in the most dynamic peaks. I think the highest I saw was still <40 Watts.

What this suggests to me is that if you have a Class A amp which will deliver a solid 30 Watts in Class A, but reverts to Class AB for headroom above this, there are probably very few occasions when such an amp will depart from Class A into Class AB, unless you have inefficient loudspeakers or are trying to fill a large room to ear-bleeding levels.

I think it needs a "pure" indicator and a "soiled" indicator that flashes on the class B peaks. Then you will know when it sounds awful.:D
 
Mmm, would they really be capable of delivering 100w class A? I very much doubt it. It is a fair point about Accuphase having a potential labelling issue.
Published specs clearly indicate pure class A operation of 100W into 8R, with actual peak output up to 190W into 8R which I take to be the Class AB mode headroom; 200W into 4R, 400W into 2R and 800W (music peaks) into 1R. If you think they're being a bit disingenuous, why not take it up with them and report back on what they say?
 
Mmm, would they really be capable of delivering 100w class A? I very much doubt it. It is a fair point about Accuphase having a potential labelling issue.
What is there to doubt? Not big or heavy enough? Each mono-block consumes 300W idling. That level of inefficiency seems reasonable for close to 100W class A. Its maximum output (into 8R) is closer to 200W, but presumably not in class A.
 
Published specs clearly indicate pure class A operation of 100W into 8R, with actual peak output up to 190W into 8R which I take to be the Class AB mode headroom; 200W into 4R, 400W into 2R and 800W (music peaks) into 1R. If you think they're being a bit disingenuous, why not take it up with them and report back on what they say?

If it is running 'pure' class A to 100 watts it would be putting out huge amounts of waste heat and consuming ridiculous amounts of electricity. Class A is a bit like having your car floored all the time and using the clutch to regulate speed. It's a wasteful design even at lower wattages, so I really hope 100 watt class A isn't the case.
 
Yes, I just don’t see the fuss around whether it is class a or not. Personally think ‘class a’ is wasteful & unnecessary, ducks for cover etc.

ATC quote that their amps are class AB, but quietly say that they are class A up to about 25w. My integrated certainly runs hot, perhaps the amps in your ATC speakers are the same?
 
So we seem to have 2 expert views that the Accuphase either doesn’t output 100W in Class A, or if it does, it shouldn’t. You can’t really win an argument like that, so I’m not even going to try.
 


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