Fred Briggs - Rangemaster MKII
The Dallas Rangemaster is an absolute classic circuit that's been around since the 60s creating killer guitar tones for guitarists such as Tommi Iommi, Richie Blackmoore and Brain May among hundreds of others. Essentially a treble booster used to push older darker amps into natural break-up it's treble laden overdrive tone is one of the most recognisable sounds in rock 'n roll guitar. Now, I like the Rangemaster but there are a few inherent problems with the design:
1) The circuit is inherently noisy producing a lot of hiss,
2) The germanium transistors required by the circuit are hugely rare and hard to source with the correct specs,
3) Due to the range of transistors used they weren't always biased correctly to produce the best tone possible.
The Fred Briggs Rangemaster MKII design looks to solve these problems and add a little more practicality and usability to this classic circuit. Noise reduction is achieved with the used of suppression choke based power filtering and ferrite bead input filtering. Using a germanium transistor in combination with a silicon transistor in a darlington configuration which is custom biased to the correct voltages ensures the best tone possible is produced by the unit. The addition of a "Filter" control (which allows you to sweep from treble boost to full range boost) and an "Aggression" control (which allows you to alter the gain of the transistor pairing from low boost to full on clipping) makes the unit much more versatile and super usable!
1 comments:
I spent much of my weekend re-designing an OC44 germanium Rangemaster circuit I built a few years ago. I loved the sound, but I used an old school metal box case much like the original Rangemaster, and as ultra awesome retro as that is, I liked having the Rangemaster sitting next to my old Thomas Organ company wah straight into my Sovtek Mig 60 head with my beloved home made more or less SG guitar with p90 pickups. With the Rangemaster it simply howls. Anyway I moved it into a case much like the way yours is , and it is so much better to use. I love your idea of having it hit a silicon transistor to so it can have the stability and predictability of a more orthodox gain pedal .
Anyway great work and ideas I relate to. I'll keep checking your site to see whats new!
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