#1
So I have this JCM800 which is a single channel amplifier. Would it be possible to have a tech making it a 2channel amplifier, and adding a master volume?

Probably stupid question - don't flame me
#3
The master volume wouldn't be a problem. You just add a pot between the preamp and the phase inverter.
The second channel would be a bit of trouble. You'd have to make sure you actually have room for the circuitry in the amp, room for at least one extra tube, make sure you transformer can handle the current draw, and wire in a relay if you want it to be footswitchable. You probably have room on the front panel for the controls though.
#4
Quote by Danyg
So I have this JCM800 which is a single channel amplifier. Would it be possible to have a tech making it a 2channel amplifier, and adding a master volume?

Probably stupid question - don't flame me


Most single channel JCM800s that I know of (2203,2204) already have a master volume?
The 1959/1987 type JCM800 circuits have two channels.

Making it two channel (2203,2204) isn't a massive job, and has been done many times successfully.
The best way is to install a relay switch to switch between the high and low inputs.
You need to bypass the 10k cathode resistor on the "clean channel" so that the volumes are close, normally there'd be a big drop in volume between the new clean and dirty channels otherwise.