Amp affected by other devices

[Danlampton]

Not sure how to describe this... I have an older tube amp plugged in to an outlet on my bench. I was letting it "cook" before I sent it home and it would make a popping sound when I turned other amplifiers off that were plugged into the same circuit.

I'm not sure why it does this, but I would like to make it stop. Is there a problem with the filtering? This could resolve some of the customer complaints with the amp.

Thanks for help.

[Jazz P Bass]

Are there any caps fixed from line wiring to chassis?
Or across the lines.
I have seen movistors attached across the line to get rid of spikes.

[TransLucid]

To expand on Jazz P Bass' comment, I've seen the ground switch cap on 2-wire AC input circuits cause noise. It's best to disconnect the ground switch when you add a 3-prong cord.

[Danlampton]

I did change to a grounded ac cord. I still use the switch (as a junction) but I removed the .047 cap. I'll try just wiring around the switch.

Thanks Jazz P Bass. I'll see what I can find tonight.

[Enzo]

I doubt you can do much about it. Certainly wouldn't be the first time an amp made a noise when the room lights were turned on, or when the sump pump kicked in.

[jrfrond]

An EMI/RFI rated line filter might help, but they are a bit pricey and I've only seen them in IEC receptacles by companies such as Corcom and Schurter.

[Danlampton]

Thanks guys. I talked to my customer about getting a power conditioner. Furman has one that isn't real expensive.