Noise with cerntain notes on my Express build

[Picker]

Away from home at the moment, but wanted to get this out there and get some advice on how to proceed.

When I play certain notes (specifically G or A) in different places on the guitar I get a static like noise from my Express. At first, I thought something was just rattling in the basement or possibly in the speaker cabinet, but now I dont think so. I think it is coming from the amp.

Any ideas on what may be causing this and what I can do to correct?

Thanks,


Royce

[Gibsonman63]

The Express clone I built does not like to be on top of the speaker cabinet with the tubes I am running. You're going to have to isolate things to see if it is actually coming from the speakers or from somewhere else. You might also try a different speaker cabinet, just to eliminate that possibility.

[jelle]

Chances are that this is a tube issue.

[redshark]

I had the same issue. It was bad solder joints. To test this get the express chassis on and connected to the speakers of course with no instrument plugged in. Then with a rubber mallet softly hit the chassis in diferent spots and then you will see depending where you hit what the bad joints are. I had 2 or 3 in the ground bar behind the pots so basically a couple grounds.
Problem gone!!

[Picker]

Thanks guys.

1. I have tried different tubes, and think I remember having the same issue with different tubes. I'll check again to be sure, but I don't think this was the issue.

2. I do not have the amp sitting on top of the Cab, so this also is probably not the issue.

3. I will check the solder joints as you suggested. Things seem to be pretty solid, but I'll go over everything with a fine-toothed comb and see if I can tighten up anything that looks loose.

I'll report back with what, if anything I can find. Until then... thanks for the suggestions.

[Picker]

Think I have resolved the issue. I'm not sure what cured the problem. I adjusted some of the wiring to be more 90 degree angles at crossing points and changed out one of the tubes.

Somewhere between the different changes I made I think I got rid of the noise.

Express goodness.

Thanks for the advice all.

[gingertube]

Had a similar sounding problem with my "Junkbox" Trainwreck.
For me it was a microphonic input tube. I found it using the tap each tube with a chopstick. Tapping V1 would recreate the problem.

Pulled the long plate Philips 12AX7A it with a modern production ElectroHarmonix. Problem solved.

Cheers,
Ian