I got to try a 50-watt Marshall JMP model today. I believe it's a 50-watt big box model. It sounded amazing. The guy wasn't sure how much he wanted to get for it. I'm not sure what year it was but it is a 4-input non-master volume model. 6550 tubes w/ a circuit board. it's definitely not point to point. The amp is a sorts hacked up. Apparently way back in the day, someone installed a fan and a male-to-male power chord so it couldn't be played with a standard removable chord. The back plate on the actual amp (not the chasis) is completely missing so there's no serial number or markings on the back at all. The impendenace selector is definitely not original. It's looks like some home made job. The pots are pretty dirty and the second input channel doesn't work all to well and the channel volume is really touchy. The first input sounds great. Other than those mods, i think it's all original. I have no idea if the amp has ever been serviced. Does anyone know when marshall made the switch from ptp to circuit board? What's a the going rate for this in mint condition? or with all these mods?