Class A, AB

Aldavis:
I am the opposite orientation on the A vs. AB choice -- after some intial experimentation and excitement about the sonic benefits of the class A mode, now I almost never go that route -- not so much concerned about the electrical use as the heat factor -- that is troublesome in a way that is not so easily overcome. Also I will say that in the case of Plinius at least, they are phenomenally close in AB, so I guess that makes me a "non-critical" listener for the most part.

Ngjockey:
According to the SA100 manual (page 6) "The current from the mains/line supply by the amplifier in BIAS A is now approximately 1,000 watts." So looks like the current draw actually is up by quite some margin to use it this way, also should be constant (see below).

Elizabeth:
Page 21 same manual:
"A class A circuit topology is one in which the total current the amplifier is capable of delivering, is kept flowing in the circuit regardless of the demand....
In a Class A circuit, current draw should be constant therefore there is an absence of the power supply modulation common in Class AB design amplifiers."

This under the heading of WHY IS CLASS A BETTER? So again, it sounds to me like these amps are switchable from Class A to AB.

>>Also I will say that in the case of Plinius at least, they are phenomenally close in AB<<

That depends to a large extent on the speaker as well.

It's very difficult to evaluate an amplifier based on one speaker.

Your Plinius may sound terrific on speaker A and like a dog on speaker B.

My analogy is also applicable to tonearms and cartridges.

Oh yes, there is little doubt that when it comes to audio review, people are not hearing the same thing. That is why the only real way to determine if a given component is for you, is to buy and listen in your own environment -- enter Audiogon.

Interestingly, I try to stay away from really narrowing down what something sounds like because of this factor, and whenever I break from that, inevitably it has a predictable result. Had a buyer recently work really diligently trying to get me to characterize the sound of a piece I was selling. I explained my position, but gave at least that it was one of the more "dynamic" pieces I had heard. He bought it, and was happy, but one of his first comments: "Does not strike me as particularly dynamic." All I could say is "there you go..."

Maich, I didn't mean to imply anything about your listening. I used quotes to emphasize that Gryphon refers to AB that way in their manual. Sorry if I offended you - jim

Oh, not at all...to tell the truth, I was not even referring to your use of the term "non-critical" -- the Plinius manual also refers to AB listening in those same terms. I was just amusing myself by restating that characterization because it strikes me as funny that my listening habits might EVER be considered "non-critical" -- I ALWAYS, even on a moment by moment basis, find something to criticize in whatever sound I have going (but nothing that ever really prompts me to want to use the Class A switch, I must say...)