anyone know where Ed ran the Channel 2 volume? I know he often dimed everything but the unused channel too? This doesnt seem to affect tone but does increase noise floor
well the input jack to V1 grid has no coax wire. I would put one instead of regular non-shielded. Start chop sticking around and move the leads to see if noise abates.
at this point Marshall is just a brand. They are putting all their eggs in the "Lifestyle Brand" strategy. Amps will be mass produced the cheapest way they can get away with. Buy a Friedman
lowering the dropping resistor will increase the B+ (more, headroom, tighter). lowering the .022 coupling cap to .0022 will reduce the bass (important to get the bass out early in the preamp circuit to reduce mush)
recently had one of these. very cool head it has a separate set of preamp tubes for each channel (lotta preamp tubes!). i needed to bias it for new power tubes and after getting a look at the guts i decided to sell the amp as servicing this would be quite a task should anything go wrong. Lots...
if i were you i'd email Dave Friedman he may be able to hook you up with someone to buy the lot at a fair price and most of all trustworthy. sorry for your loss