I have always been a fan of the Dumble Overdrive Special sound; however, I don’t need 50+ watts of power. This gave birth to the abomination that the world needed, but Dumble would have hated: The Sharkbomb Audio Womble.
For this amp, I designed the chassis using Fusion 360 and used oshcut to fabricate the actual chassis using sheet metal. I used KiCad to create the board, which I then got printed using JLCPCB.
As far as parts go, I tried to remain authentic to what I believe Dumble would have used. I used coaxial wire for most of the long wire runs, Koa Spear Carbon film resistors, and Sprague orange drop caps.
For the 1-watt power amp, I based my design off of a simple push-pull two triode design that is heavily inspired by Rob Robinette. I used a 12au7 output tube into a Hammond 125B output transformer.
I have built 2 units of this amp: one for myself and one for a teacher. One follows the typical Dumble chassis design while one is in a blackface style angled chassis, so it would fit in a spare head shell I had lying around.
All of the files for this build are on my Github.