The Fairfield Circuitry Roger That is an analog distortion pedal that takes its inspiration from FM radio transmitters and receivers. Its core is a simple JFET preamp, but the circuit adds an FM modulator and demodulator, and the maker describes the result as a volatile and unpredictable distortion12. It is a distortion pedal in the broad sense, sitting alongside other distortion pedals, but its FM-based design sets it apart from conventional clipping circuits.
How the circuit works
Delicious Audio's Paolo De Gregorio described the design this way:
"The core of Roger That is a simple JFET preamp, but by then including an FM modulator and demodulator circuit, the pedal"
In practice that means the pedal can behave like a conventional overdrive or like something stranger, depending on how much of the FM-modulated signal is blended in. The maker's own page lists the FET pre-amp as a headline feature1.
The controls: Drive, Wet, Tune and Shift
The pedal's controls split the signal path into a plain preamp side and an FM side2:
| Control | What it does |
|---|---|
| Drive | A simple JFET preamp, which can deliver a straight overdriven tone when the Wet knob is turned down2 |
| Wet | Blends in the FM-modulated signal2 |
| Tune and Shift | Set mysterious parameters of the FM circuit2 |
| R switch | Selects between two different Tuning ranges, normal and extended2 |
The Tune parameter also features a CV input, to be externally controlled by modular synthesizers or other control voltage sources, via a 1/8-inch jack2. The maker's product page confirms CV on Tune1.
The Roger That is listed as sold out on Fairfield Circuitry's product page as of 25 October 20261.
Power and specifications
The Roger That runs on 9V DC, center negative, and draws 30mA, according to RockBoard's PedalPedia listing3. RockBoard also hosts the maker's English manual in PDF form3.
Background and reception
Delicious Audio described the Roger That as "another intriguing and imaginative pedal by a Canadian company"2. The FM-radio concept has a precedent in Fairfield's own history: an earlier pedal, the RogerThat Distortion MKII, was built using multiple stages of JFET clipping, a high pass filter and an OPAMP based BODY BOOST4. Fairfield Circuitry has since continued in the same experimental territory with pedals such as the Fairfield Circuitry 20% More Slew Limiting Distortion and the Fairfield Circuitry 20% More Limiting Distortion.
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Questions
Can the Fairfield Circuitry Roger That be controlled with a CV signal?
Yes. The Tune parameter has a 1/8-inch CV input, so it can be controlled externally by modular synthesizers or other control voltage sources. Fairfield Circuitry's own product page lists this as CV on TUNE, making the pedal usable alongside modular gear as well as a standard guitar setup.
What does the Wet knob do on the Roger That?
The Wet knob blends in the FM-modulated signal. With it turned down, the Drive knob acts as a simple JFET preamp and delivers a straight overdriven tone; turning Wet up mixes the FM-modulated distortion into that sound.
Can the Roger That be used as a plain overdrive?
Yes. According to Delicious Audio, the Drive knob is a simple JFET preamp which can deliver a straight overdriven tone when the Wet knob is turned down, so the pedal can run as an ordinary overdrive before any FM character is blended in.
Is the Roger That analog or digital?
The Roger That is an analog circuit, listed as such on RockBoard's PedalPedia. Its design uses FM modulation and demodulation with a JFET preamp core rather than digital processing.
What power supply does the Roger That need?
The Roger That runs on 9V DC, center negative, and draws 30mA, according to RockBoard's PedalPedia listing. A standard center-negative pedal supply will run it.
Is the Roger That still in production?
The pedal is listed as sold out on Fairfield Circuitry's own product page as of October 2026, so it is not currently available new from the maker.
Sources (4)
- Roger That, Fairfield Circuitry
- Fairfield Circuitry Roger That RF Distortion, Delicious Audio, 2024-07-03
- Roger That by Fairfield Circuitry, RockBoard PedalPedia, 2026
- Roger That Distortion MKII, Delicious Audio, 2017-11-06
