Here’s a few shots of my latest scratch-built tube amp project: A 25W guitar amplifier using a Mojo British Vintage 12″ and other Mojo-supplied electronic components. This wasn’t a kit – I built it from scratch from the stack of parts shown. I built the cabinet, which is 16-1/2″ x 18″, out of ¾” birch plywood and upholstered it with padded tolex. I bent the preamp chassis from flat aluminum and used a pre-made BUD chassis for the amp/power supply.
Tube compliment is a 5U4, a Russian 6N2P (preamp and line out amp – it was a lot quieter than most modern 12AX7s!), a 12AT7 (tone shaping), a 12AU7 (driver), and a pair of 807′s in push-pull. The electrical circuit is similar to the rare classic 1954 Standel 25L15, with a few modern conveniences added: an external speaker jack, switchable speaker output impedance (to accommodate different outboard speakers with or without the internal speaker), a line out jack with its own level control, and a DPDT filament switch to accommodate either 12AX7s or 6N2Ps in the preamp socket. It’s smaller and lighter than the original 25L15 (36 vs. 52 lbs) and in my opinion the Mojo British Vintage 12-inch sounds every bit as good as the larger 15″ JBL D130 in the original.