cassette adapter

I recently purchased a cassette adapter on ebay, but for some reason the sound output only goes to one speaker. Am curious is this the fault of the adapter or is it just my car? When I use my radio, all my speakers work. Also my car cassette reader makes a lot of noise (not as noticeable when the music is on, but still annoying when changing track) while spinning the cassette. Is this normal? The adapter is pretty generic and looks poorly built.

Originally Posted by Sloth

The adapter is pretty generic and looks poorly built.

you gave yourself the answer.