My 78' modded JMP marshall issues

[shreddr69]

Hi all, I'm new here and was just wondering if anyone knows how I can find out exactly what mods were done to my 50 watt super lead JMP Marshall head? This thing sounds great but the foot-switch drastically alters the tone and the solo switching does not function anything like my old Quick rod ( I wish I still had!) or my buddy's Nitro and just plugging the foot-switch in kills a lot of high end in the amps sound. the foot-switch also has a channel switch, next to the solo switch, which doesn't seem to do anything. Now the amp has "modifications by splawn" labeled onto it and the name Scott Splawn is signed inside the chassis from 1993. I just want to know if the amp needs to be fixed as it seems like all foot-switch buttons should do something. The solo boost only really works if the solo volume is cranked and the amp master volume is around 1/4 or less, which is plenty loud but doesn't seem correct. Any help y'all can give would be a great help. Thanks!!!

[Ayton(e)]

First thing to do is call the shop! I doubt Scott has records going back to '93 (!) but he may well know what sort of mods he was doing to these models and understand from your descriptions what should/shouldn't be happening.

704.922.0020

I wonder if the footswitch is broken, say with the channel switch permanently on, which would explain why that switch doesn't seem to work and why just plugging in the FS causes a change in tone.

[shreddr69]

Thank you, I'll call the shop tomorrow. I appreciate the help!