36W Hiss Noise Problem

[Oldschooltone]

I Finished the amp a few weeks ago and it was working fine apart from the wiper noise on the pots, Master & Bass, I ordered a couple 1m pots replace them and bam it's done, before I replaced the pots "10 days latter" this hiss shows up.

I just figured replace the pots everything will be fine, NO. The hiss sounds like I have a Distortion pedal almost cranked with my volume on the guitar off and now wipers on the Master, Bass, Mid, & Treb make noise.

[rjgtr]

It sound like you have a bad coupling cap. Check for DC voltage on both sides of your signal caps. If you find one with voltage on both sides it might be bad (if the wiring is all correct). This could also explain some of your scratchy pot issues too. It just could be the bass cap is bad.

If that isn't it it might be some oscillation (probably ultra sonic). This is almost always lead dress (wire placement). Use your chopstick to move some wires around.

[TDuly]

Don't forget tube hiss. Have you tried swapping preamp tubes with others.

[Oldschooltone]

Still scratching my head, I changed out the .022 cap to the bass pot, back side was reading 93v and the tube side 161v after the change 46v and the tube side 161v.

I have swapped out preamp tubes tapped the wires even checked the solder to wire for ohms, I am now going to go back over the hole amp to make sure everything is correct for the third time.

[Oldschooltone]

(((((rjgtr))))) did you mean the other coupling cap, hehehe man do I feel like a moron, the voltage at both ends where almost the same and when I measured it .000, almost 500pf right.

Thank you, problem fixed and the amp sounds great.

[rjgtr]

Glad you got it!

Actually it could have been any of the tone stack caps that were leaking, but if the issue is solved, then you got it!