I love the sound of an overdriven tube amp but I also love the convenience of a battery powered, solid state amp. What to do? Enter Matsumin Valvecaster. This is a simple, low voltage pedal that drives a 12AU7 tube to pretty convincing overdrive.

I like the retro feel of tubes and I thought this clever and rich pedal circuit needed a stylish home in keeping with the feel of its main component.

I spotted 2 vintage Weston electrical meters online and the idea hit me, mount the valve externally and make a show of it. I took cues from the shape of the upper plinth and the meters viewing window and after some careful measuring of the tube, socket and meters body I made a template and cut 6 cooling fins from 2mm aluminium. After further measuring I drilled the tube hole and mounting points. I used 5mm hex stand offs between each fin. After a lot of sanding and finishing the radiator was done.

I removed all of the meters guts and external fittings and drilled where I needed to for the power input (no room for an internal battery) and pilot light ( a fender amp jewel light with a led imbedded in it with translucent silicone for diffusion. The Valvecaster has 3 controls, volume, tone and gain. The meter had 4 terminals so I fitted a 4th pot that switches on and can set the brightness of a 3mm led that illuminates the tube from below emulating a tubes glow. I drilled out the meters original brass terminal screws and used them as control knobs.

The input and output jacks fit amazingly well owing to the efficient and space saving point to point wiring of the circuits components onto the valve socket itself. I used a daughter board on the foot switch which makes true bypass, ground connections and hook ups a cinch.

And there we have it, a real tube based, Machine age style overdrive emulator pedal...as used by The Rocketeer!