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.

User Reviews

Based on 1 review Write a review

Related Products