2. amps-preamps
  3. 1217171355

Pure class A amplifiers = "slow" amplifiers?

Hi folks, I know this is subject of controversy. In general pure class A has been regarded as the best way in solid state amplification to get the purest sound. In my experience many pure class A solid state amplifiers (Accuphase, Pass Labs, Plinius) sound "slow" and are lacking "dynamics". Do they sound that way because they have less distortion than class A/B amplifiers, I mean sometimes a signal is so pure that one is increasing the volume adjustment knob to get a louder sound. With a very pure sound it seems like music goes slower too (= psychoacoustic phenomenon).

Chris
dazzdax
dpac996's avatar
dpac996
694 posts
 
No. Some of the fastest rise times are from class A.

So if this perceived slowness you think you hear from pure class a, its something else in the system

What i have experienced from class A/AB (Pass x250.5) and class A, sa102, is an incredibly dynamic and lucid presentation. A fine example of a class AB (though it is biased for about up to 5 watts in class a) was my dna 225. Also good dynamics and sense of rhythm, but outclassed by the more expensive amps ive had.

Both the pass and plinius have very "black" backgrounds upon which the musical event is built. The 225 has higher noise floor and dynamic contrasts not as extreme. I think what you are hearing is the purity of the event and maybe used to a more hyped sound from lesser amps.

just my 2 cents
audphile1's avatar
audphile1
4,919 posts
 
do you know for sure that the slow sound you have heard was attributed to the amplifiers?

I have never heard a system with a Class A amplifier sound slow. Slow sound is usually a result of overripe, fat and bloated bass. If the amps you heard possess that quality, then I guess it is what you heard.

Systems that overemphasize bass usually sound slower. Although there are amps that sound heavier in bass with softer highs than other amps, but it hardly is a characteristic of a pure Class A amplifier sound.

If I recall correctly from your previous posts, you own digital amps. Sound of digital amps is different. If you are used to one type of sound, you need to readjust and get used to a different sonic presentation if you switch to Class A amps. The sound is just different. Which is right, it's for you to decide.
kirkus
502 posts
 
The thing that makes this comparison tough is that in order to be valid, the amps you're comparing (class A to class AB, etc.) have to be the same in other ways as well . . . and this may not be the case in your experience.

I would hypothesize that the class A designs you're associating the "slow" sound with also are single-ended or zero-feedback designs that have a comparitively high output impedance, which will definately affect most loudspeakers' response in such a way as to change the way you percieve timing information.
More to discover