On Thu, 04 Nov 2004 07:56:20 GMT, "harrogate2"
wrote:

It has to be said that in the main amplifier PSUs are very simple and
usually a tad underrated - on the basis that few people can and will
run them to the limit. Voltage rail limiting and the attendant
clipping distortion is likely to set in long before that!

If you can't run a PSU to the limit, then it is over, not under rated.
And of course in any audio amp voltage clipping IS the limit for 90%
of speaker loads.

A good amp with a good regulated PSU - as designed by the sadly missed
and late John Lindsey-Hood - makes a world of difference. There you
really do notice the difference, as I'm sure Pinky and others will
agree, but in the commercial world they are very few and far between
and horrendously expensive to boot.

What difference do you think you might find? For small signals - below
clipping, that is, an amplifier will have sufficient common mode
rejection that movement of the supply rails has no effect whatever on
the signal. As you are approaching maximum power a regulated supply
will certainly hold things up better, but this really applies only if
you are playing continuous tones - the power peaks in music rarely
trouble an unregulated supply with decent sized capacitors.

I'm talking classical and similar here, not hypercompressed an clipped
pop - that will tax any power supply when driven to the limit.

d
Pearce Consulting
http://www.pearce.uk.com