In the beginning...

...there was Matsumin. This distinguished Japanese guitarist decided to create a simple Tube stompbox with a "starved plate" design based on the 12AU7 sual triode.

What he ended up with it now known as the "Valvecaster". It is such a simple project which can be essentially mounted on a noval tube socket. Anybody who is able to handle a solder can build his/her own Valvecaster. Including me! This is my very own Valvecaster

The sample was recorded with my iphone sitting near the speaker of my Vypyr. The guitar goes through the valvecaster, then into the amp. Not bad, given the recording "technique" and the fact the circuit was running off a 9V battery. Yes, because this circuit can even be fed with a simple battery. Two issues arise, however.

1. The battery will be drained at a stupidly fast rate. This is because the heaters suck up a lot of current. Even more, a tube is designed to work with a precise temperature of the filament: electrons literally boil off the filament...But only if this is hot enough. This happens when 12V are fed to the heaters (when connected in series). At 9V the filament is simply not hot enough. Indeed, the 12AU7 emits a faint glow when it is hot enough. With 9V the glow is not even there. This impacts sound quality.
2. The anode voltage is again way too low. Although this is a specific characteristic of "starved plate" projects, 9V is really too low.

For the above reasons, I dug into computer cemeteries and I found a wonderful stabilized 12V PSU which I adapted to the project. Now this led to a huge improvement in the sound quality. Which was topped only by the usage of a sweet vintage Telefunken tube. My Valvecaster 1.0 was born!