Troubleshooting Unwanted Guitar Amp Sound

[Glenn Masa]

Hi,

So my amp has developed this squeaking sort of sound (?) and I'm wondering if anyone here might be able to identify what it is. I believe it might be dust in the chassis components but wanting to get a second opinion before I go barking up the wrong tree.

Link to YouTube video of the audio https://youtu.be/C07MK2gxT8A
One Drive Link to Audio File: https://1drv.ms/v/s!ArfZ97nShOZliTBJrcUwHvprZnwz

Thanks in advance,
Glenn

*Edits: added one drive link as YouTube link not working

[Chuck H]

The video appears to be in limbo at this time. *outube instructs me to check back later.

[Glenn Masa]

YouTube route seems to be a little slow for some reason - here's a link to the audio file https://1drv.ms/v/s!ArfZ97nShOZliTBJrcUwHvprZnwz

[Chuck H]

I can hear clicks (foot switch?) and gain level changes happening. Though it doesn't seem to affect the mice. Just for clarity please:

What model amp?

Does it do this with nothing plugged into the front end and nothing in any sort of effects loop?

Do any of the panel control affect the problem?

[Glenn Masa]

Yes, so that's me unplugging the cable from the amp.

The model is a '64 Princeton Reverb RI.

Yes, the clicking sound was me unplugging to illustrate. Sorry I should have explained. Nothing in the effects loop.

That I don't know. I should also say that this sound isn't constant it does come and go but quite regularly which is a bit of a problem as I use it for recording. I'll listen again with nothing plugged in and turn each pot up to see.

[Glenn Masa]

Okay seems to be related to the treble tone control. Turned up the others also but treble showed the most notable increase of the sound.

[Chuck H]

Three suspects would be a microphonic preamp tube, failing power supply filter capacitor/s or dirty contacts. Try a different preamp tube in the first and second preamp tube slots. Contacts should be cleaned with a contact cleaner like Deoxit or similar. Including tube pins and their socket holes. I don't know how old the amp is, but I know the power supply capacitors Fender uses aren't known for their long life and sometimes they seem to go funny prematurely. So if trying different tubes and cleaning doesn't do the trick you could get a known good capacitor of a similar value/voltage spec and temprarily clip it in parallel to the preamp node filter cap. If that stops the problem I would replace all the filter caps.

[Justin Thomas]

That sounds like good old digital transmission noise to me. On top of the three things Chuck listed above, do you keep a phone or any other wireless pr electronic gadgets close to or on your amp while playing? Or even in the room...

If it's the 64 hand-wired one, check to make sure the inputs t grid stoppers are okay. I wonder if the top of the cab is shielded, also?

Justin

[Glenn Masa]

Thank you, I only got it around a year ago - but it has moved and moved back again. I'll start with switching tubes and I've ordered some deoxit. Think it'd be a good idea to spring clean regardless of if it's just a bad tube.

Hopefully it's one of the first two �� but good to know.

[Glenn Masa]

Hi Justin, Not on the amp but my phone was in the room but on on my desk away from me and my guitar.

That it is, sorry however - what am I looking for when you say t grid stopper? The top of the cab is shielded not to say that that shielding might have been damaged somehow?

[eschertron]

Does changing the amp's physical location make a difference? For instance, rotating it 90 degrees (if it's facing south, turn it east). Or moving it across the room or into a different room. If it's picking up interference, you can sometimes troubleshoot - even identify the source of the EMI - by moving the amp around, using it as a detector.