So I built my guitars. I showed them to my friends and after ‘Dude, you should build an amp for that now,’ I Googled ‘Marshall schematics’ and ‘how not to get killed by high voltage amps’ and did my research. My grandfather was a professional electrician, so I approached the project with some kind of hope that a few of his genes made it into me. I settled on building a 50 Watt JCM800 – 2204 like everybody else did. By the way, a really great source of information is Rob Robinette’s Tube Amplifier Website, Designing Tube Preamps for Guitar and Bass by Merlin Blencowe, and Nik at CeriaTone.
The amp was ready, now I needed a speaker cab. A 2×12 should do it. I used 15mm birch plywood and the speakers are two Celestion Vintage 30’s. The open back panel was not calculated for certain frequencies, I just simply ran out of plywood and now it serves as a great storage place for cables, a guitar stand, extension cords and other junk gathered after a gig.
I soon realized I’d like to use both High and Low inputs while playing. So after going back to Blencowe’s book and reading a chapter on relay switching, I gutted out the amp and rebuilt the preamp section. I split the tone stack for both channels, keeping the low the Marshall way and trying a little bit different cap values for the high gain.
