ThorpyFX Fat General

The ThorpyFX Fat General is an analog optical compressor pedal made in the UK by ThorpyFX. Its circuit is a reworking of Dan Coggins' Dinosaural OTC-201 Opticompressor, a now-discontinued pedal whose design, in Coggins' words, "lives on in a new guise: as the Thorpy FX 'Fat General' Compressor"¹. ThorpyFX and Coggins collaborated on the pedal, which MusicRadar describes as "based on optical circuitry and offers two modes of parallel compression where some of the dry signal is mixed in proportion with the compressed signal"².

The core idea is parallel compression: instead of feeding your whole signal through the compressor, the Fat General keeps a portion of your dry, untouched signal and blends it back with the compressed signal. ThorpyFX says the pedal "adds sustain and balance to your signal without unnecessary noise or signal 'pumping'", staying transparent with sparkle and clarity³. On That Pedal Show, the presenters noted that "there are loads of players who are using this as their always-on pedal"⁴.

What it does: an optical compressor with a parallel blend

Optical compression uses a light-dependent element to control gain reduction, which typically gives a smooth, gradual response. The Fat General's circuit follows the OTC-201 optical design⁸, and Aion FX notes that the pedal "adds a treble control to allow a more jangly tone to be dialed in, but is otherwise basically the same circuit as the original"⁹.

The pedal runs in two modes, both built around parallel compression²:

• Blend mode: the Balance knob mixes dry and compressed signal from fully dry to a full parallel mix².
• Juicy mode: the blend is locked at 90% compressed and 10% dry, and the Balance knob becomes a volume control⁸⁷.

MusicRadar's Trevor Curwen found Juicy mode delivers "smooth, fat compression that can get nicely squashy at higher settings yet delivers a consistent snappy sharpness at the start of notes"².

The controls

The control set is small: three knobs, a mode switch and, on the MKII, an attack switch⁵¹⁰.

Guitar.com's review notes that with the blend disengaged, the balance control becomes "a volume knob, with a certain amount of clean boost"⁵. The same review advises that "you'll need to exercise restraint with the sustain control here to keep things sounding natural"⁵. MusicRadar found the Treble knob "voiced just right to add a bit of sparkle"².

Power and connections

The Fat General runs on 9V DC, center negative, drawing 35mA⁶⁷. The original version could also run on a battery, though one was not supplied⁵.

Connections are a TS input and TS output⁷, with input impedance of 10M and output impedance of 39K⁶. The MKII has recessed knobs and top-mounted jacks⁶. The pedal uses buffered bypass rather than true bypass⁵. Internally it is built with 1% metal film resistors, Wima and Panasonic capacitors, Neutrik jacks and a Burr-Brown opamp, on a gold-plated PCB with dust-sealed potentiometers⁸.

History and versions: the Dan Coggins design and the MKII

The Fat General's lineage goes back to the Dinosaural OTC-201 Opticompressor, designed by Dan Coggins, co-founder and co-designer of Lovetone pedals². That pedal is now discontinued, and its circuit was reworked for ThorpyFX: on That Pedal Show, it was described as "a sort of re-imagination of that circuit with a couple of extra cool features and it's been tweaked"⁴. Guitar.com's review of the original Fat General appeared in August 2018, marking the start of the Thorpe/Coggins collaboration¹¹².

The pedal has gone through versions:

ThorpyFX states plainly that the MKII "is sonically identical to the V1 version", with the V2's changes being the smaller black anodised aluminum enclosure⁶. A MAUD Birthday Cake Edition of the MKII also exists, from the same ThorpyFX/Coggins collaboration¹²⁶.

The enclosure design is shared across versions: a stainless steel laser-etched center console wrapped in a tough baseplate⁶.

What reviewers said

Reviews have been positive across the board. MusicRadar called it "a high-quality and easily set up compressor that has the added flexibility of two flavours onboard", praising its solid build quality, while noting one drawback: "Engaging the pedal in some settings in Blend mode can give you quite a large volume jump that may or may not suit"².

Guitar Pedal X's reviewer, comparing it against other compressors, wrote:

He described it as "an amazing soft, subtle and incredibly natural sounding compressor on Parallel / Blend Mode" and "the simplest one here but all killer"¹⁰. Delicious Audio's reviewer was likewise "very complimentary" about the pedal⁸.

That Pedal Show demoed the pedal in October 2018, walking through both modes and the balance control's dual role, and noting how many players use it as an always-on pedal⁴.

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