Buzzy hum

[Utopia]

My Crack + Speedball has a buzzy hum that becomes audible when I turn the volume pot up to 50 % or more. I believe I had it before the speedball upgrade, but then at 80-90 % and up. I have tried different tubes with no change. The noise is also the same if I disconnect the DAC from the input.

After reading the forum I'm pretty sure I have a bad solder joint somewhere, but from the information above, is it possible to pinpoint where it could be? Before or after the volume pot?

Thanks in advance!

 

[Doc B]

If it goes up and down with the volume knob you know the problem is ahead of, or at the volume knob. It could be your cables. Try shorting the RCA jacks and see if it goes away.

 

[Utopia]

Thanks, I'll try that!

Good to know the problem is ahead of the pot. Then it shouldn't be too difficult to solve.