I recently purchased an MP3 player and tried running it thru the Bose cassette player using one of those cassette adapters. I get a loud humming noise thru the speakers. Anyone have the same problem?. It may be I bought a cheap adapter (Coby). I don't think its the player since it sounds great in my truck ( I don't need an adapter for the truck - I can go directly into the headunit). I know I could use a source switching relay instead and go directly into the amp but it seems like a lot of work (too lazy to run wires

 

dont use a cassette adapter to begin with, they ruin the tape head in the cassette deck.

If you must use it, try switching the play direction on the deck.