The Matsumin Valve Caster is a very underrated little circuit, with almost no decent demos online.  The only demos I could find either sounded kind of terrible, which is nothing like my build, or they are attempting high gain sounds, which is something this just doesn't do.  

The Matsumin Valve Caster works best as a clean boost, through to a medium amp like drive.  I know everyone says that their pedal sounds 'amp like' this one really does.   It does react well to being pushed with a booster, and if you hit it really hard it becomes very squishy with very obvious sag.

The tone control is not all that useful, as it's not a bright sounding pedal to start with.  It could probably be completely removed from the circuit, or replaced with a low value capacitor directly to ground to tame the highs a little.   Matsumin did intend this to be used with single coil pickups, and on some settings a tone control is useful (bridge pickup as an example).

The maximum voltage for a 12AU7 heater is 12.5v, so you can run this at 12v if you wanted to, or even higher if you know how to reduce the voltage to the heater (otherwise you will cook the valve very quickly).  A 12AX7 will not work, a 12AT7 is said to be passable.

Oh yes, if you try and run this off a 9v battery - it won't work.  The battery can't provide enough current to run the Valve Caster.  If it does work, it will only work for a short time as it sucks the life out of the battery.

MATSUMIN VALVE CASTER - POINT TO POINT LAYOUT

note: I used a 1uf as an output cap, where the original calls for a 470nf.   Easy to swap if you prefer to stick with the original.

MATSUMIN VALVE CASTER SCHEMATIC

12AU7 / EC882 DATA

MATSUMIN VALVE CASTER ON THE SCOPE

Input signal:  440hz sine wave, approx 130mv TRMS

Gain at 0

Gain at 50%

Gain at 100%