http://www4.head-fi.org/forums/showthread....&threadid=43771

Those with external USB sound cards, go get a linear regulated wall wart... it could potentially improve things quite a bit. Those cheap 10 cent Chinese AC adapters deliver dirty and unstable power.

Edit -- of course, it could be that the AC adapter (Creek OBH-1) in the comparison at the link above was designed poorly on purpose so people would upgrade to the $100+ Creek OBH-2... "Audiophile" equipment can really be a joke sometimes...

Wall warts rated for audio use also have caps across the bridge diodes to slow the turn-on and turn-off. I'm not a big fan of wall warts though. Always a little trickle of primary current driving up your electric bill.



mobius

Can you disconnect the ground wire of the Elpac ? Or plug in into a two-pins plug ? We know that using a ground wire for turntables, plugged into the ampli, greatly diminishes the background noise. Actually, I wouldn't even think about listening to a vinyl without the ground plug, so much hum it generates when it is unplugged.
In this case it would have nothing to do with the quaility of the power supply itself.

That's an interesting idea, to see how much of it is due to grounding. If I can find a grounded plug to two-pin adapter, I'll give it a try.

I suspect a lot of it wasn't grounding, as the noise floor was fluctuating so much with the Creek PS... hum is usually a steady tone that doesn't cause the noise floor to fluctuate between -90 and -60dB rapidly. After amplifying/listening to the recorded files, I didn't hear what sounded like a 60Hz hum in it either.

If you like, I can provide 2-second FLAC files of the Creek's noise floor using each PS... I saved them for the possibility that someone might want to see the results.

Edit -- here's an interesting link related to this subject:

http://www.tangentsoft.net/audio/opamp-ps.html

I don't think a new wall wort would help my USB sound card ( http://www.edirol.com/products/info/archive/ua3.html ) since it gets its power from the USB cable. Of course the PC gets its power through a power conditioner/filter.

On my previous computer, I couldn't touch both the parallel cable from the printer and the PC case ! There was too much voltage between them. Not enough to paralyse my hand but enough to make me drop it. And when the parallel wire was being plugged into the computer, blue sparks could be seen on the plug when it was touching the other plug.

Just to illustate how crappy power supplies can be.

Hey I had the a similar problem between my '286 PC and the radiator...

When we took out the multimeter, it showed a voltage difference of ~114V !

Problem vanished with my next computer case (and PSU).