Pure class A amplifiers = "slow" amplifiers?

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.

Hello,

I know Guidocorona was just joking with his post. ... but ... I just would like to clarify for those who may not know. The tempo of a song ( how fast or slow it is played ) has nothing to do with the time signature. Two totally different things.

Best,
Tom

Thank you Tom, sadly, you are correct. Performers often take obscene liberties with clearly specified time signatures or stylistic practices, resulting in totally bizarre tempos of performances and recordings.
Rythmic signatures are a different matter all together, and are subject to their own special kind of manglings.
Eldartford, you are right of course, about time domain compression/expansion. I have played with analog time domain compression of speech streams since the mid 70s. . . . and in those days results were pretty horrendous. Now days, using advanced algorithms, reasonable intellegibility can be achieved by speeding up digital recordings of speech up to 3X. Text to speech engines (TTS) can yield intelligible speech upwards of 500WPM by adopting differing compression scales for different phonemes. I have heard formant-based TTS engine actually running at 1200WPM, but do not pretend to understand them at such speech rates. G.