Marshall Super Lead Reissue Master Volume Pop

[Greg_L]

Or it could be that the new shielded cable just has a closer spacing between the shield and conductor. Making it more capacitive. Small shakes now as the problem is solved. Sort of...

I never saw a stock 1959 with a shielded lead for the inputs. But this IS a reissue with a different board and I can't say if Marshall did this or it was added. Regardless, like I mentioned before, the bright channel on these amps can be a marginally stable circuit in my experience. Maybe there's some mojo there? As in when it's only just stable it's good and when it's more stable it's just ok.?. I don't know, food for thought though.

I've seen a small handful of 1959 and 1987 reissues that oscillate and need to have the grid wires and grid stoppers removed from the board and run straight to the tube pins from the jacks. The board layout itself is a little different from vintage PCBs, and the voltages are higher and the resistors are small metal films. Maybe that has something to do with it? I'm not sure. Running shielded cable and carbon film grid resistors right at the tube pins usually takes care of it.

[GoldtoneWorkshop]

Or it could be that the new shielded cable just has a closer spacing between the shield and conductor. Making it more capacitive. Small shakes now as the problem is solved. Sort of...

It was a different type/brand of coax so you may be on to something

EDIT: Carbon composition plate load resistors are notorious for hiss. They have a different construction that is a prone to very tiny arcs in higher voltage circuits that can sound like crackling, but sometimes hiss. If there are carbon comp resistors in the plate load circuits you could change them to metal film and it MAY make an improvement. Maybe not.

This amp does have carbon comp plate resistors on V1, so I'll try swapping those out. Thanks for all the info!



EDIT:

I swapped out the two carbon comp plate resistors on the first gain stage with metal oxide resistors. There is still hiss present, but to me the pitch of the hiss has gone down so it seems less noticeable.