The Collateral FX Complex is an analog overdrive pedal from Collateral FX built as a Marshall-in-a-box: a single pedal intended to reproduce the sound of a range of classic Marshall amplifiers rather than one specific circuit. RockBoard's PedalPedia describes it as "the most complete Marshall-in-a-box you'll find on the market today," and says its J-Fet circuitry covers "the entire range of the most sought-after Marshall sounds in history," including 1959 Plexi, JCM 800 and JTM45 tones1.
What it does
The Complex is a preamp-style overdrive in the Marshall-in-a-box tradition: instead of pushing an already overdriven amp harder, it aims to put the character of several British amplifiers on a pedalboard. The maker's product page describes the pedal as covering 1959 Plexi, JCM 800 and JTM45 tones, three amplifier voicings that sit at different points on the gain spectrum, from the earlier, lower-gain JTM45 and Plexi sounds to the hotter JCM 8001.
The circuit is built around J-Fet transistors rather than the op-amp and soft-clipping arrangements common to many overdrives such as the Boss SD-1 or Ibanez TS9. The maker presents this as the reason the pedal can cover that range of amplifier sounds in one box1.
Controls
The pedal gives the player two tone-shaping controls, which the maker describes as independent of each other1:
| Control | What it does |
|---|---|
| Tone | Shapes the overall voicing of the overdrive |
| Treble | Adjusts the top end separately from the main Tone control |
The maker's page states: "With independent Tone and Treble controls, you can shape your sound even more personally." Having the two controls separate means a player can darken or brighten the overall drive and then add or cut top end without re-voicing the whole pedal, which is useful when switching between the lower-gain JTM45-style settings and the hotter JCM 800-style settings the pedal covers1.
Who it suits
The maker positions the Complex as a pedal with a wide range of British voicings rather than one fixed gain point. Its product page says: "Guitarists from blues to metal will delight in the sounds this Marshall machine has to offer," placing the pedal's usable range from blues through to metal styles1. Players comparing it against other drives may also want to look at the wider field of overdrive pedals and distortion pedals to see where a Marshall-in-a-box sits relative to a straight boost or a higher-gain distortion.
Power
The Complex runs on 9V DC with a center negative plug, as listed on the maker's product page1.
Use a 9V DC center negative supply. Before sharing a power supply with other pedals on a daisy chain, check the maker's current draw specification for the Complex.
Videos
Flavio Versiani
Questions
What kind of pedal is the Collateral FX Complex?
It is an analog overdrive pedal built around J-Fet circuitry, described by its maker as a Marshall-in-a-box. According to the maker's product page, it covers the range of the most sought-after Marshall sounds, including 1959 Plexi, JCM 800 and JTM45 tones, in a single pedal, with independent Tone and Treble controls for shaping the sound.
How is the Collateral FX Complex powered?
The pedal runs on 9V DC power with a center negative plug, as listed on the maker's product page. As with any 9V center negative pedal, use an isolated power supply rather than a battery or an unverified daisy chain, and check the maker's current draw specification before sharing a supply with other pedals.
Sources (1)
- Complex by Collateral FX, RockBoard PedalPedia, 2026