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Triton Mk. III Preamp Drive

Based On
Dirty Little Secret Mk. III
Effect Type
Overdrive / Amp Emulation
Build Difficulty
Project Summary
An adaptation of the classic Marshall® amplifiers from the 1960s. It uses cascaded mu-amp stages in place of tubes for amp-like tone in a small box.
Triton Mk. III Preamp Drive printed circuit board

Printed Circuit Board

What's included?
PCB only. Build instructions and parts list can be viewed or downloaded from this page.


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Complete Kit

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Project overview

The Triton Preamp Drive Mk. III is an adaptation of the Catalinbread Dirty Little Secret Mk. III, their “amp in a box” voiced with a Marshall amplifier in mind. This third version was released in early 2013.

The Formula 5F6, released a few months later in the summer of 2013, is the same circuit with several tweaks in part values to make it more like Fender’s tweed Bassman amplifier from the late 1950s (which was Jim Marshall’s source for the first Marshall amps). With the Triton PCB, you can build either the DLS or 5F6, as well as the hotter “Red” special edition of the DLS from 2019.

The production version of the DLS includes an internal slide switch to go between “Super Lead” and “Super Bass” modes. This slide switch has four poles, with two poles controlling the gain and two poles controlling the tone stack. The Triton splits this into two discrete toggle switches so you can switch the gain and tone stacks independently, e.g. the gain of the Super Bass but the tonestack of the Super Lead.

Like several other Catalinbread pedals, this circuit blurs the line between a preamp and an overdrive. Like a true preamplifier, it’s very reactive to what comes before it, so it’s best placed after other drive pedals but before modulation. However, it also generates more than enough drive on its own and can be used as a standalone overdrive pedal just like any other.

The original DLS Mk. III used MPF4393 JFETs, which are no longer produced. Aion FX sells the original MPF4393 in sets of 5. The PCB also has an extra pad so that surface-mount JFETs can be used (part number MMBF4393), which are still in production and perform identically to those used in Catalinbread pedals. See build notes for more details.

The Triton Mk. III is compatible with the 18V Voltage Doubler / Bypass module if you want to run the circuit at 18V without an external adapter. The higher voltage provides increased volume and clarity.