http://www.dazatronyx.com/class-a-germanium-amplifier/ The Germanium Amplifier+ is a vintage voiced boost that can smash your amplifier hard in the face. It can be used for volume boost and shaping, or for additional drive pushing a gain stage.
The Germanium Amplifier+ is constructed with a 'tin can' PNP germanium transistor. The germanium transistor has a rich history in musical effects for its round and life-like sounding properties. Germanium transistors were used before the introduction of silicon and have become increasingly difficult to find in acceptable condition with low leakage and suitable gain. I have been collecting germanium transistors in bulk supplies since I was in high school.
Each transistor is selected for over-all excellence and will always have its own sound. Each circuit is individually biased and tailored to suit the characters of the transistor. The circuit squeezed maximum use out of the transistor and runs with a little bit of its round break up.
A silicon selection switch has been added to the Germanium Amplifier+. Silcicon can be used for less background noise and a sharper clipping.