The Copilot FX Trek is a fuzz pedal built around pulse width modulation: as Copilot FX's product page puts it, "The signal at the input is converted into a square wave with an adjustable amount of the on/off time of the wave." In practice that means a squared-off, gated fuzz voice whose character shifts as you change the width, from fuller and bassier to thin and trashy. It also has a dedicated oscillation footswitch for self-generated pitch effects, and an expression jack that opens the pulse width up to external control.1
Guitar Pedal X's Stefan Karlsson, writing in May 2026, describes Copilot FX as "the now alas defunct Dominican Republic's Copilot FX", so the Trek is no longer in production. He notes the maker "did various 'Trek' editions of that same kind of circuit over a decade", including a large scale Custom Trek with 8 knobs, 3 toggle-switches and 2 switches, alongside 6-knob Compact Trek editions.3
Controls and footswitches
The Trek's controls come from Copilot FX's own manual and product page.21
| Control | What it does |
|---|---|
| WIDTH | Sets the range of the pulse width of the fuzz signal; fully right gives more bass, decreasing it makes the fuzz voice more thin and trashy2 |
| DRY | Adds the signal at the input, to allow more clarity and control2 |
| VOL | Amount of fuzz volume at the output2 |
| Oscillation toggle | Selects oscillation type1 |
| Momentary switch | Activates the oscillation1 |
| Oscillation footswitch | Activates the oscillation; set the amount to the proper oscillation pitch frequency2 |
| Bypass footswitch | Activates the pedal2 |
| LED indicator | Red when the fuzz is on2 |
The oscillation footswitch is the Trek's second performance control alongside bypass. Copilot FX's manual directs you to set the Amount to the proper oscillation pitch frequency, so the width control shapes the pitch of the oscillation as well as the fuzz voice. The momentary switch on the product page activates the oscillation too, giving a hold-to-swell way to bring the effect in and out mid-phrase.21
Expression and CV control
The expression input is a TRS jack for external control of the pulse width, accepting either a TRS expression pedal or a 0 to 5V CV signal.21 That makes the width sweepable by foot, which is where a pulse width fuzz earns its keep: the same control that thins and trashifies the voice by hand can be ridden dynamically. Copilot FX lists the Trek's expression jack as compatible with its Broadcast, Broadband and Bandwidth pedals, and the jack takes a TRS expression pedal of the kind covered on the site's expression pedals page.1
Power, jacks and size
The Trek is powered only by its DC 9V power jack, center negative, with no battery option, and the manual calls for 10mA or higher.21 A standard 9V center negative output on a pedalboard supply covers it.
The input jack takes signal from your instrument or the output of another pedal, and the output jack feeds other FX pedals or an amplifier.2 The enclosure measures 4.5" x 2 1/2" x 2 1/2", with silk screened artwork in enamel ink on a powder coated aluminum case.1
Where it came from
Guitar Pedal X's Stefan Karlsson traces the Trek to the Blarg o-tron o-tron kind of circuit, describing it as a super rare design that Copilot FX built various Trek editions of over a decade, from the 6-knob Compact Trek up to the most expansive Custom Trek with 8 knobs, 3 toggle-switches and 2 switches.3 With the maker now defunct, the Trek survives as one of the pulse width fuzzes in that lineage, alongside other Copilot FX designs like the Copilot Fx Mantis, Copilot Fx Orbit, Copilot FX Caracol and Copilot Fx Terra.
Videos
Copilot Fx
Copilot Fx
Disarm D'arcy
Questions
Does the Copilot FX Trek take a battery?
No. Copilot FX states the Trek is powered only by its DC 9V power jack, center negative, with no battery option. Plan to run it from a pedalboard power supply rather than expecting to drop a battery inside.
What power supply does the Copilot FX Trek need?
The Trek runs on DC 9V with a center negative plug, and the manual calls for a supply of 10mA or higher. Any standard 9V center negative output on a pedalboard power supply meets that requirement.
What does the Amount knob do on the Trek?
The WIDTH control sets the range of the pulse width of the fuzz signal. Fully to the right it provides more bass; decreasing it makes the fuzz voice more thin and trashy. The same width can also be controlled externally through the expression jack.
Can I control the Trek's pulse width with an expression pedal?
Yes. The expression input is a TRS jack that accepts either a TRS expression pedal or a 0 to 5V CV signal, and it gives external control of the pulse width. Copilot FX lists the Trek's expression jack as compatible with its Broadcast, Broadband and Bandwidth pedals.
Which Copilot FX pedals work with the Trek's expression jack?
Copilot FX's product page lists the Trek's expression jack as compatible with the Broadcast, Broadband and Bandwidth pedals. The jack itself takes a TRS expression pedal or a 0 to 5V CV signal for external control of the pulse width.
How big is the Copilot FX Trek?
Copilot FX gives the Trek's dimensions as 4.5 inches by 2 1/2 inches by 2 1/2 inches, a compact enclosure finished with silk screened artwork in enamel ink on a powder coated aluminium case.
Sources (3)
- Copilot Fx Trek Pulse Width Fuzz Pedal, Copilot Fx, 2017
- Microsoft Word, Copilot FX, 2015
- Guitar Pedal X, Guitar Pedal X, 2026-05-08
