Catalinbread Knight School Synth

The Catalinbread Knight School Synth is a DIY kit synth pedal: you buy it as a bag of parts and a labeled circuit board, solder it together yourself, and end up with a pedal that converts your guitar signal into a square wave whose pulse width you can shape by hand or sweep automatically with an onboard LFO¹. It sits in Catalinbread's Knight School line, a family of build-it-yourself pedal kits that also includes overdrive, fuzz, filter, bit crush, distortion, delay and tremolo circuits¹²³.

The synth voice at the heart of it comes from pulse-width modulation. The LFO varies the pulse width at a speed and intensity set with the knobs directly adjacent to the LFO toggle, which is how the pedal moves from a steady synthetic voice to a sweeping, raygun-like motion⁴.

What the Knight School Synth does

The pedal's core effect is a pulse-width modulated version of your input signal. Pulse width is what determines whether a square wave sounds thin and nasal or fat and hollow, and having it under a knob, and under a moving LFO that varies the pulse width at a speed and intensity set with the knobs adjacent to the LFO toggle, is what gives the Knight School Synth its synth character. Compared with polyphonic pitch-tracking synth pedals, which analyze your notes and rebuild them as synth voices, this is a simpler, more direct approach: the wave itself is reshaped rather than resynthesized⁴.

The LFO is the motion source. With the LFO toggle off, the two knobs beside it do nothing; with it on, the LFO automatically varies the pulse width at a speed and intensity you set¹. Turned down, the LFO softly shifts the pulse width; all the way up, the most dramatic effect is heard⁴.

The controls

Catalinbread describes the control set in its own words on the product page⁴:

The layout tells you how to use it: the toggle gates the modulation, and the adjacent RATE and DEPTH knobs shape it. With the LFO off, the pedal behaves as a static pulse-width synth voice; with it on, the same voice starts moving¹⁴.

Power: 9V, center-negative

The Knight School Synth accepts a center-negative DC power supply capable of supplying 9 volts and at least .5mA of current, with higher current being fine⁴. That is the same power arrangement Catalinbread specifies across the Knight School line, from the Fuzz to the Filter, Bit Crush, Overdrive, Distortion, Delay and Trem²³⁵.

Kit build and mods

The Knight School Synth is sold as a kit, and the build is aimed at people learning to solder. The circuit board has everything labeled as to what part goes where, so component placement is spelled out rather than left to a separate diagram¹. That matches the philosophy Catalinbread has applied to the whole Knight School range: Guitar World reported on the line's Overdrive kit in 2023, noting you need a soldering iron to piece the pedal together, and Gearnews observed of the Fuzz kit that the DIY build option is around $50 cheaper than the built version and the circuit does not contain a huge amount of components, making it a way to teach yourself the basics of pedal building⁶⁷.

Because you build it, you can also change it, and Catalinbread points to two specific component swaps on the product page¹.

LFO speed range. The 4u7 electrolytic capacitor governs the range of the LFO rate control. Bigger values shift the range down, so the RATE knob reaches slower speeds; smaller values do the opposite, pushing the whole range faster¹. If the stock range feels too slow or too fast for the parts you play, that one capacitor is the part to change.

Low end. In this circuit, the 100n capacitor is the output capacitor, and enlarging it slightly enhances the low end of the circuit¹. For bass players, or guitarists who want a thicker synthetic body, that is the bass mod.

Both mods are single-component changes on a board where every position is labeled, which makes them reasonable first projects for a builder who has finished the kit and wants to go further¹.

Where it sits in the Knight School line

The Knight School Synth is one circuit in a broader Catalinbread series of DIY kits. The line includes an Overdrive based on the stock TSF circuit, a Fuzz with silicon 1N4148 clipping diodes, a state-variable low-pass Filter whose RESONANCE knob introduces feedback to make it more "synth-like", a Bit Crush descended from Catalinbread's Heliotrope, plus Distortion, Delay and Trem offerings². The Filter in particular overlaps in spirit with the Synth: both lean into synth-style sounds, the Filter through a resonant low-pass sweep and the Synth through pulse-width modulation and its LFO.

Where the rest of the line covers conventional gain and time-based effects, the Synth is the line's odd one out, the kit to pick if the sound you want to build toward is a square-wave synth voice rather than an overdrive or a delay⁸⁹.

Questions