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
Other than making sure your power is enough to command the A1's, maybe the accuphase pre is adding some fudge...nice sounding but not speed racer! Try a used Krell stereo amp with a KCT...should be warm and fast.
Guidocorona...Believe it or not audio can be speeded up without the tonal change that results from overspeeded playback...but no using a simple amplifier. It takes some digital processing.

It is a fact that our sense of hearing can recieve and understand speech faster than our tongues can wag. Alarm messages, for example to airplane pilots, can be speeded up.
Class A (in general) will produce less distortion than any other form of operation. The human ear uses odd-ordered harmonics as loudness cues; in particular the 5th, 7th and 9th. Although only found in trace amounts in most amplifiers, even very subtle increases in these harmonics are readily noticed due to the way our ears work.

We perceive the increase as brightness/hardness.

I would not surprise me in the least to find that some people hear that as 'speed' (to me the word speed refers to the risetime or slew rate of the amp) or bandwidth.

If those harmonics are not altered the amplifier will be more relaxed or 'laid back', which is **not** to say that there is a coloration- in fact. there is *less* coloration.

In transistor amplifiers some of the fastest risetimes are manifested in Class A amplifiers. This is true of tubes too, although to really get the same speed as transistors you have to get rid of the output transformer, but then they can be every bit as fast as the fastest transistors.
"Speed" or more properly "rise time" should never be a problem for audio amps. After all, both tubes and transistors are used at radio frequencies.