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The build was based on a JTM-45-inspired Mojo kit but souped up with a few JCMstyle touches and, of course, many custom Egnater mods. There were some nice surprises, like the cathode follower – a circuit where the output is taken from the cathode instead of the plate, making it easier to drive the tone controls while creating killer harmonics when overloaded – and a choke, which filters some of the DC hum before the juice hits the screen grids.
We followed the schematics as Bruce and his staff explained what we were doing for eight solid hours – even longer for those of us who weren’t technically inclined to begin with. As each person finished up, Bruce went through their amp and tidied things, correcting mistakes like the red and green wires that my slightly colorblind eyes misread on the schematic, rerouting connections under something instead of over it, or even resoldering buzz-prone areas like pot grounds.
Our moments of truth came during a final check. Every circuit was tested with a voltmeter, which ferreted out additional problems that some of us had to correct. Tubes were matched and biased. Bruce also showed us how to read a scope and plot output signals.
When all systems were go, it was on to the sound booth in the back of the shop where our still cabinet-less amps were plugged into a 4x12 cab and put through the paces. Each person stole away to that little room like a purse-snatcher slipping into an alley to check out the loot. We’ve all test-driven amps before, but nothing compares to plugging in and firing up your own creation for the first time. After 10 or 15 minutes of the happiest noodling you’ve ever heard, each person walked out of that room cradling their amps like newborns.
To sift through amp building theory on the second day was indeed well thought out. The hours of assembly and instruction from the day before were put into macro and micro perspective. We also spent significant time talking about future mods – the changes in tone that would take place by switching this cap here and that resistor there. The last thing we did was drop our amps into their cabinets – a process akin to mounting a prized image into a frame, complete with the desire to take a few steps back and look at the finished product from different angles. Talk about a room full of swelled chests.
Building your own amp is a powerful experience that is especially rewarding when instead of sounding like a run-of-the-mill kit amp it sounds better than anything you’ve played through before. It’s also an invaluable process for personal growth as a player; after building an amp from the ground up you’ll suddenly hear things that you’ve never heard before. I’m already jonesing to build another one.