JFT Class-A Transistor Colour


  • Full Kit
  • Step-by-Step Guide
  • Supported
  • Intermediate

Thick, musical saturation that shines on any source.

Part of the magic of vintage solid-state gear is that, because transistors were expensive, they used as few as possible, so each one had to work harder. And when transistors are pushed to their limits, they begin to distort in beautiful ways. The JFT Colour is designed by this philosophy: choose great-sounding transistors and then make them work very hard.

The JFT employs two class-A saturation stages to create a complex, layered character. In the first stage, a NOS JFET generates asymmetrical distortion, clipping the bottom of the waveform but not the top. This type of saturation, which is associated with triode tubes, thickens and warms up the signal while maintaining its integrity. In the second stage, five transistors form a primitive discrete opamp which operates just on the verge of instability. This stage applies a subtle layer of harmonics which give the Colour a “finished” sound.

MKII Improvements

In 2019 to celebrate the fifth anniversary of the Colour Format, we redesigned the first three Colours, the 15IPS, CTX, and JFT, to use only discrete, class-A transistor circuitry. You could think of this as the opposite of an update—we’ve reversed the technology of the Colours back to the late 60’s. The result is an authentic vintage character that’s more nuanced and refined.


  • Discrete, class-A saturation circuitry
  • NOS 2SK170 transistor for musical, tube-like harmonics
  • Compatible with the Colour format
  • Blue PCB
  • Full, step-by-step assembly instructions and guaranteed support

Real analog plugins.

Colour is a new format for analog audio gear designed for and by the DIY community. We took our favorite sounding analog circuits and put them on modules that are small, affordable, and swappable.

The Colour format consists of Colours and Palettes:

Colours are ultra-compact, pluggable analog circuit blocks that impart various types of analog color. Check out our ever-growing selection of Colours. Colours can be designed and released by anyone.

Palettes provide controls, power, and support circuitry for Colours. We currently offer the Colour 500 Palette and CP5 Mic Preamp with Colour.

Customer Reviews

Based on 2 reviews
Paul Najar
Nice Colour

This was my first colour build. It was easy and quick. The sound is great for a transistor based saturation even at hi gain. It doesn’t seem to crap out very easily. It’s early days but so far I like it on guitar and am keen to try on bass and and vocals. We shall see. Recommended.

Joseph Chudyk
Instant Beautiful Mixable Distortion

I've also been using the mkI for five years. The mkII has so much more of a smoother distortion characteristic that I find myself reaching for more and more in a mix. Right now I have a pair set up for a parallel mix that I can send any element in Pro Tools to for added weight, warmth or pure destruction. It offers a different harmonic flavor that the other colour modules don't offer. Again, another piece of my setup that I can't do without.

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