I have got what sounds like an alternator whine but it only comes on badly
when the cassette unit of my in dash Sony is being used and then it is only
really bad whtn I turn the air conditioning on:

I tried putting a Pyramid NS21 20 amp high suppressor Isolation transformer
just between the phono imput and the amp which is directly next to the
battery in a hole below the floor of the trunk in my car but it makes it
about 3000% worse. Is there some trick to using these suppressors? Must it
be nowhere neat the amp or no where near th e battery or something or is
this just a loust suppressor or a faulty one? (The instructions don't say
anything about it needing to be grounded or anything so I tried just hanging
it loose on the floor of the trunk to see what effect it had on reducing the
whine and as I say it made the sound completely unbearable)

Licensled to Quill