HT1R Microphonic tubes

[oly2b]

I am problems with buzzing at specific fretted notes (similar on three different guitars), it went back to Blackstar they said the tubes needed changing, worked fine for a bit then same problem, changed to a fresh pair of JJ tubes fitted end of January which worked but now same problem.
No buzzing on when on headphones, using a 1 x 12" cabinet, tried differ positions of the HT1 but still there.
Is two months normal for tube life? Any ideas what to try?

[thephantum]

Since there is no buzzing on headphones, something is resonating with particular notes...and since it keeps coming back, it's something else in the amp that's vibrating.

If it's still under warranty, take it to an authorized service center for repair....as the next steps I would take in troubleshooting will definitely void that warranty.

[oly2b]

Hi
Thanks for the replay. The amp is outside its warranty period now and as already been back to the manufacturer's once.
I did notice on Monday when doing the pencil test (chassis open and powered up) there was no problem, but when firmly screw back together it started again, EQ set at zero also helps and get worst when been on for a long time.

I have also noticed some light brown stuff around capacitors C57/C58 (2200uF 25V) and over what could be the fuse (X1), Is this some form of seal or leaking electrolite?

Regards

Craig

[thephantum]

My guess is you are seeing a foam adhesive used to keep certain components from moving around.

Based on the symptoms, I think you might have at least one cold and/or cracked solder joint someplace.