Class A and B differences?

Have you been leaving the Pass amp fired up 24 / 7 ? If not, try doing that and see what you think of it. Give it three days of "steady AC burn" before really giving it a good listen. Things may settle even more after that point, but they will be very gradual and take an extended period of time. The 72 hour "settling period" will give you a good idea of what the amp sounds like with the rest of your system. Sean
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Personally, I think that 10%-15% is a pretty good increase in performance, when you are getting up into the higher levels. Remember, you get into that "diminishing returns" area at some point, where you have to pay alot more for each little increase in performance. At the top of the scale, a 15% improvement would be astonishing, and costly.

As far as Class A and Class B are concerned, the quality of implementation is the key, and not always just the A or B classes that may make the difference. A real good Class B design may sound better than an inferior Class A amp. It is generally accepted, though, that well done Class A amps will give the most sonic purity.

I can't comment on your exact comparison, as I have no experience with those amps personally.

And yes, the quality of the speakers and source will have a direct bearing on the sound that you get out of the amp.

I've owned amps that were rated class A up to a certain output and then transitions over to class AB. I can't say I've have heard much of a difference. Basically, class A amps have their output devices on all the time, where as class B devices are on only 1/2 the time. One device handles the positive waveform and another handles the negative. The crossover point is where distortions can occur. Whether it's audible or not depends on the resolution of your entire system. Not to nitpick, but when you mention class B I believe you are refrring to class A/B. Class B amps are very efficient but would not really make a good audio amp.

Jim

"but when you mention class B I believe you are refrring to class A/B."

No, I think he's right. "Class" A/B (althought there are plenty on the market) really isn't a class: its an amplifier that goes from class A mode into class B mode when the power demands reach a certain level. Randy Slone and Douglas Self among others cover it pretty well (saying exactly that) and many of their designs are Class B. I've seen other artcles on the internet that'll even state "Class B amps aren't used in Audio" and I don't think they know what they're talking about entirely. Incidentally, he does have a Spectron which is a Class D circuit and "even worse" than class A or B--loosely speaking. As TWL put it "the quality of implementation is the key."

I believe there have been a few previous threads on the subject in the archives now to help answer the original thread/question--can't vouch for the content though, but....

I retract partially--you may be right on the Class AB. But they both seem to be of the impression that to quote "Class AB is less linear than either A or B" and "is not really a seperate class of its own..." Or "Class B is by far the most popular mode of operation...." and many of there designs are just Class B. Parasound, Adcom, and Magnum Dynalab all claim Class a/b in many models. And Perraeux has that weird Class a/ab, which got me thinking more about what you said cause that would make sense for ab to be real, just a little weird.