Custom 2204 build, low output fuzzy distortion

[Pochie45566]

Hey, I received this 2204 type build, made small changes where necessary to make it more like a original 2204 with just some cap values and resistors. Replaced all pots, electrolytic caps, all that stuff. Only mod is someone put a 5u4gb rectifier tube in. However the amp crackles a bit, and distortion is very fuzzy. Low voltage maybe? Where should I start.

[TIMBO]

Hey mate, Crackling sounds like a cold joint or bad/loose ground connection.
A schematic of what you have and voltages off each pin on the sockets and at "node" of the power supply.

[Pochie45566]

This is basically it, all the voltages present in the schematic are present or very similar to what im reading in the amp. Anything specific youd like me to check? I can get those tomorrow for ya.