Hi all, I was wondering if anyone could tell me of an appropriate forum to try and get some basic help diagnosing an old valve amp i bought. I suspect it may need new valves or a transformer. I'm not afraid to get my hands dirty with a multi meter but i'd need step by step help on what to test. Basically when i turned it on with nothing plugged in it started to crackle loads and changing the volume knobs effected the crackle like a very dirty pot would but didn't seem to impact the volume of the crackle. I plugged a guitar in and with a little twiddling the noise settled, it was working with a really rather nice crunchy tone for all of about 20s then the volume slowly faded away to nothing and it wont make a sound. Is this typical behaviour of a certain failed component? The amp is a fairly unknown one from the late 50s/early 60s. A dallas scala. valves are i beleive 1 x EZ81 rectifier, 1 x ECC83 and 1 x EL84. Only one of these is uncovered the EL84 i assume but i can see it is lighting up. There is now nothing coming out of the speaker not even hiss.