snap almost Cured the main troubles in valve preamp and amp, suspect EL84 and 2 badly soldered pcb wire links (lead free solder again, note only 2 or 3 years olkd) . But there is a low level throbbing rumble noise obviously associated with the tremolo oscillator on the effects board, as it cycles up and down with varying tremolo pitch and depth. The owner lives with this but is there a simple cure, assuming its a grounding/screening/decoupling/smoothing problem.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on