"Eeyore" wrote in
message
Arny Krueger wrote:

"Eeyore" wrote
Adrian C wrote:

Use a PC switchmode power supply?

To make it sound REALLY crappy ?

I've run a lot of audio gear off of PC power supplies
without bad things happening.

Car audio stuff is pretty happy running off of the 12
volt lines, which have pretty impressive current ratings.

Car power rails are massively noisy so if course they're
designed to cope with that.

But the 12 volt rails in PCs aren't all that bad.

I just probed the major DC lines that supply the hard drives in an
operating PC with my Fluke 85. As you probalbly know, the Fluke 85 is not
one of those meters that rolls off jst below 1 KHz like many, but is pretty
flat up to 100 KHz or more. It's less than 0.1 dB down at 20 kHz.

The 5 volt supply line had less than 1 mv of broadband AC on it.

The 12 volt supply line had less than 4 mv of broadband AC on it.

I've seen a lot of switchmode supplies in DVD players
and the like.

So ? You can make an SMPS very quiet if you know how. I
do for example.

My point is that:

Just because its a switchmode supply, it doesn't necessarily create problems
with sonics.

The classic 300 watt ATX PC power supply is not all that shabby.