Help me diagnose my (probably user-induced) intermittently crackling tube guitar amp!
Okay, here are the data points:
-- Brand new Blackheart BH15H
head, worked fine out of the box
-- I installed the Bitmo Triple Bypass mod
myself (which involves soldering in a three-way switch and couple of capacitors and resistors).
-- After the mod the amp works as expected -- overall tone much improved -- but produces a 'bacon frying' crackling and noisy volume pot when I first turn it on. After about 15 mins to half an hour, the noise goes away and it works silently.
-- I have checked all my solder joints and they seem solid
-- I have swapped out both the tubes and it makes no difference
-- I have cleaned the volume pot, no difference
At this point I'm suspecting either (1) a dry joint that I can't find which is closing once the innards of the amp warm up or (2) some DC across the pots from a leaky cap, but can't understand why this would clear up once the amp gets warm.