Hi sometime ago I asked Steve about an intermittent crackling problem with my amp. On switching the amp on there would be a crackling noise fading to silence. Other times it would work fine. Steve suggested that I go to a reputable electronics guy. I found this guy Cyril Ryan of Audiotronix at Unit 9, Moycullen, Co.Galway. I left the amp in with him and after two hours he came up with the solution as follows: This maybe of some help to somebody.
Got the bastard J
It was a dry solder connection on the phase splitter board (small valve before the output valves). The fault appeared only once ...and only for about a minute but I was able to isolate it to this board. Inspection of this board with a high magnification loupe revealed that one of the resistors was not soldered properly.....must have been troublesome from day 1.
I have re-soldered the joint and tested the unit. All is fine. Beautiful amp.