I have an original tuber driver by BK Butler, not one of the ones made by Chandler, but one of the original BK Butler models. If you know who BK Butler is, I need say no more.

The question I have is this: The tube they used in the pedal is a generic 12AX7 and it is really muddy when I use anything other than a guitar with a single coil in the bridge position.

Can anyone recommend a replacement tube that is twangy? Should I call Groove Tubes and talk to them about it?