Yes psu noise in analogue circuits is something I find I get on usb powered
devices. It seems to be on the earth as well. Some devices are more prone
than others.
It seems to be a factor of many tings particularly computer usb sockets.
Brian

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"Dave Plowman (News)" wrote in message
...
Have a few devices in the AV setup which are USB 5v powered. To try and
keep things as neat as possible, all the mains to that are now IEC, as
that takes up less space than 13 amp.

So decided a USB power supply would be nice. One where the PS was internal
rather than a wall wart, and a main cable I could fit an IEC plug to.
Found one on Ebay with 8 outlets - not cheap either.

One of the things it would power being the a Toslink to phono adaptor -
TV audio into the amp. Which was just fine on its supplied 13 amp wall
wart. With a USB to USB lead.

I now get a noise like a distant burglar alarm on its output with the new
PS. ;-) Changed back to the original PS, OK.

Not a ground loop either. Happens with only it plugged in.

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*El nino made me do it

Dave Plowman London SW
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