JDM Pedals “OC Boost” is a compact modern recreation of the classic “Rangemaster” circuit. Our modifications include an “EQ” knob, which progressively blends in more low frequencies, and a “hi cut” switch to adjust the very top end of the response. We build this pedal using original “black glass” OC71 and OC44 transistors. Other transistor models have become increasingly hard to source. Contact us if you would like to order one with OC75, OC72, OC42, OC45, etc.

Order the JDM “OC Boost” w/ OC71 Valvo “Black Glass” Germanium transistor:

Order the JDM “OC Boost” w/ OC44 Valvo “Black Glass” Germanium transistor:

Order the JDM “OC Boost” w/ Custom Choice Germanium transistor (email Joe first for options!):

A Classic Guitar Effect – Overdriving the Amplifier Itself

The basic feature set is the “boost” control (naturally), and the “EQ” control. With the “EQ” set fully counterclockwise, you have a classic treble boost. This effect was popularized in the 60’s when british made amps were voiced fairly “dark”, and boosting the treble created a one-two punch of increased clarity and a boosted signal, overdriving the input stage of the amp, and creating singing sustain.

Clapton used the treble boost style Rangemaster for his immortal “Beano” sound, whereas Tony Iommi of Black Sabbath used a modified “full range boost” to craft proto-metal sounds. Our boost features an adjustable EQ range, from full-range to treble boost so you have those classics plus many shades in between.

Modern components, Vintage tone

We use modern components on a copper ground-plane board to ensure the quietest possible operation with a circuit that is notorious for creating noise. High tolerance resistors allow accurate biasing to hit the “sweet spot” on the transistor. Proper grounding ensures that stray noise is not amplified.

The analog voltage inverter allows you to run the pedal on either 9v block battery, or a standard, center negative (“Boss style”) power supply. So this boost can be daisy chained with other pedals, despite the vintage Ge transistor!

As the original Rangemaster was voiced to boost the input signal to darker sounding vintage British amps, we’ve added a “cut” to tame harsh highs. The 3-way top-cut switch allows you to shave off “harsh” or “brittle” tones from the signal. It’s a 3-position switch with center off (off is classic rangemaster response). The other two positions we set to “just take off the edge” in one position (can help cut hiss or interference if you experience it at a gig). The second cut “warms up” the tone, just right for brighter American amps (Fender, Boogie…).

*NOTE – the demo video is from some years ago, when we had *plentiful* OC75, OC44, etc – we do still have a limited quantity, so contact us if you prefer a different transistor, as this listing is for OC71 only, as long as those last!


Naturally, anyone who is getting a handmade vintage Germanium boost pedal at this quality and price is in seventh heaven. Here’s a good example, from our seller page on Reverb.com:

Our Return Policy

If you’re not satisfied with any JDM Pedal, you can return within 14 days for a refund (minus shipping and payment processing costs, which Paypal does not refund to us 🙁  If you encounter any functional problems with a pedal at any time just contact us! Since we use vintage transistors, it is possible that a transistor can fail, as rare as that is, and we’ll always do what it takes to get your beloved fuzz machine growling again.