Tube amp picking up radio frequencies

[admin_exported]

I have a tube amp, a Jolida JD502BRC, and a preamp, a Jolida JD9, that's picking up radio frequencies. I can hear faint voices and radio programs when not playing LPs.

Any idea where that's coming from...?!

The turntable is grounded. I turn off the turntable but still hear radio activity. I have noticed I only hear these sounds when the turntable is selected on the amp, not the CD player, etc.

I've been doing some tube rolling, not sure if I heard these sounds when I had the original tubes in place. Do you think it's the tubes???

 

[Anonymous]

I think you've already partly diagnosed the problem.

1) Disconnect the turntable at the power amp end. (i.e connection between pre-amp and power amp)

2) Can you still hear the radio sound on the speakers when this is the selected source?

3) If yes then the problem lies within the amp

4) if no then the problem lies within the preamp or the turntable.

5) Reconnect the preamp and disconnect the turntable from it. Can you hear the faint radio noise?

6) If yes it's a pre-amp problem. Are thre any inductors in the input side of the pre-amp circuit?(sorry don't personally know your amp).

7) If no it's probably to do with the lead from the turntable to the pre-amp. try replacing this.

 

[Anonymous]

No 7 is the culprit!

The turntable is a Music Hall mm 7.1, I'm using the stock cables that came with it, they're grounded to the preamp. I could try changing the cables if I can find another set with a ground connector. Very annoying!

 

[Anonymous]

I fixed the problem by replacing the stock Music Hall cables from the turntable to the preamp with high quality shielded cables. Radio interference disappeared immediately.

Yeah!