Man alive! I had the input and output wired wrong. Sounds great with the Mullard OC71. I really like the 9V sound but would be upset if that was all it did - the higher voltage adds an amazing amount of body. Really digging it on bass with a lot of low cut.
I'm having some issues with my Duocast build - there is a terrible jagged hum overwhelming the base sound.
The low cut works, the lo channel works (but with a massive hum) and the hi channel seems to have no effect. I can't see any solder bridges and the parts all seem correct. But voltages not...