Why is there an annoying hum in the background when I listen to my lp's?

Question

I have a turntable connected to a stereo receiver. It plays well and sounds good but there is a loud hum in the background. I was recording lp's to tape, and the noise comes through on the recording. Any recording enthusiasts out there?

Answer 1

Commonly this is caused by an earth loop (power travels on the earth between devices) and is added to the audio signal or the turntable could be floating above earth and picks up electrical noise.
If the turntable is not earthed, it should have an earth connection on the audio cable (RCA) or it may need a separate earth on the back of the turntable to connect to the back of the amplifier.
Try connecting a bare wire between the turntable earth connection (it will be a screw on the back of the metal chassis if it has one) and the earth screw on the back of the amplifier.

Answer 2

you're not grounded....
If you've connected the lp to the computer directly...
you need an adapter....
best adapter is a Reciever with a phono jack.

http://www.ramelectronics.net/html/howto-pc-audio.html
Connecting a turntable (phonograph) to your computer.
You cannot connect a turntable directly to your computer. Why? A phono cartridge puts out an extremely small signal, which has a rather strange frequency response curve (due to RIAA equalization). A phono preamp is required to boost the signal and "straighten out" the frquency response. This is why you must plug a turntable into the "phono" input of a reciever or Amplifier rather than the "Line" or Tape inputs. Therefore you must connect the turntable to the Reciever, and then connect the Tape outputs to the computer, using the computer as you would a tape deck.

Harder to find these days....
A isolation transformer...GREAT for killing hum

AHA here's one....
http://www.ramelectronics.net/html/GLI1-X1.html

for more info about your problem.....
http://www.jensentransformers.com/an/an004.pdf
ORIGINS OF HUM
Often sound systems exhibit strange and perplexing behavior such
as hum that appears and disappears when power to other
equipment, not even part of the audio system, is switched on or off!
Traditional methods to eliminate hum often seem more like voo-doo
than engineering and, more often than not, are trial and error
exercises that end only when someone says "I can live with that".
This author has previously written about balanced lines in audio
systems, so this paper will be strictly confined to unbalanced
systems.[2]

Hope I helped you!!

-dawgy