I'm now a convert to mains conditioning. For some reason (??) my huge 25A
variac seemed to have a beneficial effect on smoothness and detail. Encouraged,
I bought an EPI mains conditioner, essentially a large toroidal isolation
transformer. This was smoother and more detailed again. So:
a) what mains conditioners are you using?
b) what effects do you observe?
c) where is this detail coming from - is it possible there's some compression
going on, or is it just more resolution and less interference?

Andy

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

In article ,
Andy Evans wrote:
I'm now a convert to mains conditioning. For some reason (??) my huge 25A
variac seemed to have a beneficial effect on smoothness and detail.

Have you had a look at your mains with a scope to see what artifacts it's
removing?

--
*Happiness is seeing your mother-in-law on a milk carton

Dave Plowman London SW
To e-mail, change noise into sound.

I have a scope but I'm ashamed to say I haven't yet got around to using it.
Andy

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

In article , Andy Evans
writes
I have a scope but I'm ashamed to say I haven't yet got around to using it.
Andy


Well it might be instructive to see what's on the waveform and then look
at the HT rails in your amp.....

--
Tony Sayer

In article , Andy Evans
wrote:
I'm now a convert to mains conditioning. For some reason (??) my huge
25A variac seemed to have a beneficial effect on smoothness and detail.
Encouraged, I bought an EPI mains conditioner, essentially a large
toroidal isolation transformer. This was smoother and more detailed
again. So:

I assume you are asking comments from everyone? If so...

a) what mains conditioners are you using?

Some 'RS' RF filtered mains distribution boards. Plus one I made myself
ages ago with some larger ferrite inductors. None with any 'audiophile'
pretentions.

b) what effects do you observe?

Meridian 200/263, Power-amps and my own preamps: Nil.

Quad 34 and my old cassette deck: reduction in sensitivity to mains carried
pops and clicks. FWIW I like the Quad 34 a lot, but I find it does pick up
mains clicks more easily than I'd like. I suspect my DVD recorder and the
Quad FM tuner may be sensitive as well, but haven't checked as I decided
just to use them via spare sockets in the RS boards.

c) where is this detail coming from - is it possible there's some
compression going on, or is it just more resolution and less
interference?

Afraid I have no idea as I don't know enough about your designs, nor about
the state of your 'raw' mains power. So can't really say.

However with poor PSUs I'd tend to expect a change in the details of the
mains buzz that comes through, particularly when the power amp is under
load. May also let through more RF. If the amp's bias and operation is rail
sensitive, changing the effective rail impedance may change the amp's
behaviour in more dynamic ways. Can only generalise and speculate without
knowing a lot more about the situation.

Some amps may also be affected by having RF on their power rails. However
my reaction has been to try and eliminate this by design of the amp and its
PSU, not by adding external units for conditioning.

FWIW One of the tests I did (many!) years ago was to use one d.c. coupled
amp to supply one of the rails for another. Then waggled the rail in all
sorts of ways whilst the amp was playing music. This allowed me to check
that - provided the amp didn't clip - there was no audible effect. However
I would not recommend this test for every design I've seen. :-)

Slainte,

Jim

--
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Andy Evans wrote:

I'm now a convert to mains conditioning. For some reason (??) my huge 25A
variac seemed to have a beneficial effect on smoothness and detail. Encouraged,
I bought an EPI mains conditioner, essentially a large toroidal isolation
transformer. This was smoother and more detailed again. So:
a) what mains conditioners are you using?
b) what effects do you observe?
c) where is this detail coming from - is it possible there's some compression
going on, or is it just more resolution and less interference?

Well......

The power supply in any amplifier doesn't affect compression or the like. It just
supplies DC voltage(s) to the innards.

If you knew the waveforms in the PSU you wouldn't be worrying about treating the
mains in an audiophool manner.

Likwise - the idea of RF getting onto power rails is grossly exaggerated.

If you're *really* getting any difference ( try measuring ? ) then I'd suggest you
need to take a look at your incoming mains. It must be awful in some unknown
respect ( gross interference from industrial plant ? ) for any of the above to have
any audible effect.


Graham

If you're *really* getting any difference ( try measuring ? ) then I'd suggest
you
need to take a look at your incoming mains. It must be awful in some unknown
respect ( gross interference from industrial plant ? )

No industrial plants I know of. The differences with a mains isolation
transformer are subtle, but audible and very satisfying in fact. There's always
a danger of trying to seperate binaries such as "theory versus practice" on
this ng, and I'm simply reporting what I hear in this instance. It may be the
case that 'if you can hear a difference there's something grossly wrong' but I
somehow don't think there's anything grossly wrong anywhere in this case.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

"Andy Evans" wrote in message
...
If you're *really* getting any difference ( try measuring ? ) then
I'd suggest
you
need to take a look at your incoming mains. It must be awful in some
unknown
respect ( gross interference from industrial plant ? )

No industrial plants I know of. The differences with a mains
isolation
transformer are subtle, but audible and very satisfying in fact.
There's always
a danger of trying to seperate binaries such as "theory versus
practice" on
this ng, and I'm simply reporting what I hear in this instance. It
may be the
case that 'if you can hear a difference there's something grossly
wrong' but I
somehow don't think there's anything grossly wrong anywhere in this
case.

=== Andy Evans ===
Visit our Website:- http://www.artsandmedia.com
Audio, music and health pages and interesting links.

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!

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.


--
Woody

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

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!

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.

Indeed they are, mand despite its well-known problems with capacitive
loads, the real strength of the Naim NAP250 is that it does have
excellent regulated supplies. That is the main reason why it appears
to be horribly overpriced for its power rating - much like my '50
watt' Krell! :-)

--

Stewart Pinkerton | Music is Art - Audio is Engineering