The Dallas Rangemaster is a treble-boosting guitar effects pedal from the 1970s. Plenty of good info online about these units; for a brief history, take a gander at this article.
The original Rangemaster is an extremely simple design: it's essentially a high pass filter combined with a small amplifier. The key to the design is the use of a single germanium transistor; this device's unique (and usually undesirable) electrical characteristics make for a unique tone.
See, pretty simple, right? In the last few decades a number of clones have improved on the original design a bit; it seems like some folks will putz about with the 0.0068uF cap value to change the bass attenuation, and using an NPN transistor (rather than a PNP unit) is handy as it pulls ground negative. In any case, it seems like step zero is to find a source of good condition NOS (new old stock) germanium transistors. I think this circuit might be best suited to copper ground plane construction to improve noise performance, which will be a new one for me.
Anyone out there in project land ever built a Rangemaster clone? I'm not a guitar player, so this stuff is all pretty unfamiliar.