Hum in Speakers - AMP switched to Phono

The hum is a typical problem from a turntable. the turntable needs to be GROUNDED! to the preamp... if you preamp has a ground screw sticking out somewhere on it's backside: the turntable (motor)is what is usually grounded there.

Elizabeth is right again, but you might also need to check your outlet as well. I had a situation in my house where the plugs were replaced (old two prongers to "modern" three prongers) but they didn't actually ground the outlets - hence, looked good, didn't ground a thing. Being a former builder, I rectified said stupidity (actually re-wired the outlet, since not only wasn't it properly grounded, they had the polarity reversed as well - "egads" says I), and lived hum free thereafter. I'll probably be chasing down this problem on every plug in the house for a while, but at least I've got good music to accompany me!

chas

Something else to consider re: ground loop problems. CATV lines are a common source of ground loops if you have a TV connected to the receiver, and a CATV line going into the TV (or VCR or whatever). I had a ground loop problem related to a CATV line, and for some reason I only heard hum or buzzing through the phono system (probably because it's a lower level signal). The problem was solved by inserting a Jensen isomax transformer before the cable box, cost around $50. www.jensentransformers.com