The idea behind the Kalamachamp was to build a single ended harp amp that was not just another Fender Champ clone. I had heard good things about the early 60s Kalamazoo 1&2 models, which had very simple circuits, so I looked around to see what parts I had to commence the project. I had a pair of suitable transformers, but the PT did not have a 5v rectifier winding. I had a nice cabinet from a 1950s tape recorder, and a standard chrome tweed champ chassis. Well, that's a start. The final result exceeded my expectations. If you jump to the video at the end, you'll see why. Anyhow, here's the circuit I came up with.


I decided to use a 6X5 rectifier, which has an indirectly heated cathode and a 6.3v heater, so all three tubes could be run off the same transformer secondary. The 6V6 output tube only has 215v on the plate, but the amp is plenty loud and nicely gritty.

I've never given much credence to the online fuss about different tone capacitors, but I'm beginning to think that some of this amp's mojo comes from the vintage 'black beauty' caps I used. Here's a shot of the amp with the hinged back off.



 Modifying the cabinet was a challenge for someone with zero woodworking skills, particularly cutting the speaker hole without ruining the vintage vinyl, but the result was satisfactory. The choice of  an Italian Jensen C10R speaker gave the amp a satisfying bark, while keeping plenty of low end in the mix.

If you would like to hear the beast in action, here is a YouTube link. The video was filmed in my garage with Joris Kostelijk playing a Hohner harp in A, through a Greg Heuman 'Bulletini' mic.