"Richard Crowley" writes:

From your description, I can only assume you are refering
to "hum". There are several good tutorials on eliminating
hum (caused by ground loops, etc). Google returned more
than 7000 hits for ground-loop hum. The reason you couldn't
find what you were looking for is that you were using the wrong
term. "Hum", not "feedback".

Check my tutorial at
http://www.epanorama.net/documents/g...oop/index.html

Ground-loop hum from cable-TV connections is a
common problem and there are vendors of isolation
transformers that break the ground loop. For example...
the "VRD-1FF Cable TV Ground Loop Isolator"
from http://www.jensentransformers.com/

Isolation transformers for audio (for your computer
connection) are also available in many places.



--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/