I finished building my crack a few weeks ago and so far I'm pretty happy with it.
Today I installed the Speedball upgrade.
Unfortunately I don't get any sound now. All LED's light up and the tubes are also heating up.
There is a distinct crack/pop a few seconds after turning the amp on. But no loud buzzing or humming and it is silent otherwise.
My voltage readings:
OA 114,7V
OB 110,2V
G 0V
B+ 190V
OA 74,7V
IA 190V
B-A/B 0V
IB 190V
OB 84V
The mains voltage is 230V.
Any help is appreciated.