Radio signal coming through pot

[Ang]

I get a radio station signal through my speakers depending on where the volume is set on my tube integrated. It occurs with seemingly random intensity at different positions of the volume control. I've pulled the pot out and sprayed it with deoxit but the problem remains. Would replacing it solve the issue? Thanks.

 

[dmills]

The problem is unlikely to be the pot, and is probably poor design for RFI immunity.

a few hundred pf from whatever connection the RF is getting in on (may not be the obvious input leads) to case ground (with the leads kept short (as in way less then an inch)) may help matters or get the manufacturer to ship you something built right in the first place....

In fact a smallish cap across the pot might do it (depends a bit on the amp topology), recommending a value is tricky as that pot could be anything from 4K7 to a meg or more.

Regards, Dan.

 

[Ang]

Thanks for the advice. The pot is a Noble 100K pot. I'd like to try putting a cap across the pot as you suggested.

However, it has six connections, with multiple wire going into it. There are 8 connections coming out of the pot itself. I'd tried to find two with variable resistance while changing the volume, but that didn't seem to work. Do you know where I would connect the cap to be "across" the pot? Thanks.

 

[Jan Dupont]

Try make a connection between Volume pot thread/shaft to Ground

 

[Ang]

Ahh, IC, thanks. Have a 10uF cap I'll try connecting from the shaft to the case.

 

[Geek]

Ahh, IC, thanks. Have a 10uF cap I'll try connecting from the shaft to the case.

No, try a 0.01uF or 0.1uF ceramic.

Your bypassing RF, not audio. Electrolytics are useless here.

Cheers!