Help! Constant underlying fuzz/distortion under clean tone

[juneaudio]

Hi all,
I have a GDS kit that I built many many years ago which just always has had a fuzz/distortion underlying the clean tone regardless of volume, and especially noticeable of course at lower volumes when you expect things to just be clean. Its very hard for me to say if this is the "18 watt fizz" that its so often discussed, but I feel like it might be a different problem.
I have re-flowed every connection as well as tried multiple good sets of tubes and still the issue persists. It is the same for both channels. I figured Id upload some photos and just see if any of you experts are willing to have a look and see if you notice something off.

Thank you!

[juneaudio]

Decided to upload an audio sample, volume is on 1, and amp is not loud at all, so I would expect just a clean tone, this is from a Strat with single coils. Any thoughts? Could my output transformer be bad?

[Bieworm]

Sounds like sympathetic vibration. Can you hook another amp to the cab you’re using?

[juneaudio]

I have the amp out of the cab for testing, so I dont think its the cab getting to the amp, but I also tried another cab and same result unfortunately, really confused at this point!

[Iain T]

Do you have a load box with DI out to remove the cab from the equation altogether?

I've got a cheapo Bugera unit that does the trick as it has a DI and phones out on it with bearable speaker sim!

[JMPGuitars]

Start by posting your voltages. Use one of my charts from the downloads section...and fill out the whole thing.

It could be a few different things causing the issue. Assuming there isn't an acoustic guitar in the room pickup up the sympathetic vibration, it could be a number of electrical issues in your circuit that might cause this.

Likely unrelated to your issue, but grab some IPA and clean the flux off your board and solder joints.

You can also apply the Ruby mod just to rule it out.

Thanks,
Josh