JFT Class-A Transistor Colour

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. Features 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 Samples Resources Assembly Guide Schematic (PDF)