On 2017-02-13 16:03:55 +0000, Eiron said:

On 13/02/2017 15:26, Jim Lesurf wrote:
In article om, mick
wrote:
Hi Brian, You don't mention which unit you have, but I'm using a
Behringer UCA202 feeding a home-brew headphone amp. There's no apparent
background noise at all. I'm using a quite good quality lead between
the Behringer and the amp to prevent noise being introduced here. I've
not got any sort of fancy power supply or earthing arrangement.

Brian mentioned his having a ground terminal. The UCA202 I have doesn't
provide one of those. So he may have a variant that includes an RIAA
preamp.

The UFO202 has line/phono input and a ground terminal.

If using a laptop it can help to disconnect the power and do your work
on battery.
And also checking the earthing. One path to earth is better than none
or several.

When I had this problem some while ago between an iMac and a fixed HiFi
system using an M-Audio DAC, I guessed that it was an earth loop
problem and tried transformer coupling the audio. That cured it.

I believe that this whine is a quite common problem and there are
readily available USB isolators that will break the earth connection on
the USB lead.

Arthur

--
real email arthur at bellacat dot com