Keep Stan Ricker or your favorite test LP nearby at all times. My wife mentioned that on side was louder than the other. Using Ohm Walsh speakers, I don't always notice an in-balance! First I tuned to an FM station and everything sounded fine. Could have also used a test CD. Then I put on the Cardas test LP. Stan's voice was much weaker on the right than the left. Examining the needle under magnification revealed a small piece of dust clinging stubbornly. A light cleaning with the appropriate brush and all is well.