The Colortone ZeroSum is a full-stereo dual-head delay pedal from Colortone Pedals. Guitar Pedal X priced it at $249 when it covered the pedal, and noted that as of the review the price was £187 direct (£249).1
What it does
The ZeroSum is a rhythmic delay: rather than a single repeating echo, its modes and pattern styles let you set up multi-tap delay figures across both channels of a stereo rig. The Audio Matrix switch sets how the pedal handles mono and stereo signals, with MM for mono, MS for MISO and SS for full stereo, and a Spread control sets the stereo width of the repeats. A Tone control adjusts brightness and a Repeats control sets how many times the delay trails around.1
Guitar Pedal X reviewed the pedal and noted its pricing at the time: £187 direct (£249), with the pedal listed at $249 in the United States.1
Controls and footswitches
The pedal splits its controls across two layers. Layer 1, marked in red, carries the main delay controls; Layer 2, reached by press-holding a footswitch (indicated by a green LED), carries the presets.1
| Control | Layer | What it does |
|---|---|---|
| Rate | Layer 1 (red) | Sets the delay time |
| Delay Mode | Layer 1 (red) | Selects Single Head, Dual Head or Echo Pong |
| Delay Style | Layer 1 (red) | Selects Mode A, Mode B or Mode C patterns |
| Delay Mix | Layer 1 (red) | Blends the delays with the dry signal |
| Tone | Layer 1 (red) | Adjusts brightness |
| Repeats | Layer 1 (red) | Sets the number of repeats |
| Spread | Layer 1 (red) | Sets the stereo width |
| A / B / C controls | Layer 2 | Select presets P1 to P3 |
Two footswitches sit at the foot of the pedal: the left one is Tap Tempo and the right one is Bypass. Press-holding brings up Layer 2, where the A/B/C controls become the preset selectors for P1, P2 and P3, shown in amber, red and green respectively. Tap tempo needs three taps to lock in.1
The ZeroSum runs on 9V DC center negative power and draws 145mA, a current draw well above what a battery or a standard daisy chain supply is likely to spare, so plan your power accordingly.1
Stereo, MIDI and expression
The rear panel carries a TRS input and a TRS output, MIDI In and MIDI Out, the Expression CTRL jack and the power inlet. The expression input works as a multiplier running from x1 to x3, so a connected expression pedal can sweep a parameter across that range. The MIDI connections let the ZeroSum take commands from, and report to, other MIDI-equipped gear.1
Power
The ZeroSum runs on 9V DC center negative and draws 145mA. That is a heavier draw than many compact pedals, so a daisy chain shared with several other pedals may not be the right home for it; a supply with enough current on a dedicated outlet is the safer match.1
What reviewers said
Guitar Pedal X is the main published reviewer of the pedal so far. Its review noted the price at the time as £187 direct (£249), with the pedal listed at $249 in the United States.12
Colortone also makes a Lo-Fi Delay, a different take on delay in the same range.1
Videos
Mike Hermans
Brett Kingman
Brett Kingman
Questions
Is the Colortone ZeroSum analog or digital?
The ZeroSum is a digital delay. Guitar Pedal X lists it among digital delays, and it runs on a custom Electrosmith chip onboard. It offers Single Head, Dual Head and Echo Pong delay modes, each with A/B/C pattern styles, so the character of the repeats depends on the mode and style you select rather than on analog circuitry.
How many taps does tap tempo need on the ZeroSum?
Tap tempo on the ZeroSum needs three taps. Guitar Pedal X's review notes that three taps are required for the Tap Tempo, which is worth remembering when you are setting the delay time on the fly from the left footswitch.
How many presets does the ZeroSum have?
The ZeroSum has three presets, P1 through P3, accessed through Layer 2. The A/B/C controls serve as the preset selectors, with P1 shown in amber, P2 in red and P3 in green. A firmware update released in November 2025 added smarter preset switching, including combined two-footswitch preset switching.
Does the Colortone ZeroSum have MIDI?
Yes. The ZeroSum has both MIDI In and MIDI Out on its rear panel, alongside the TRS audio input and output and the expression control jack. That makes it straightforward to sync the delay with other MIDI-equipped gear on a board.
Can the ZeroSum run in stereo?
Yes, the ZeroSum is a full-stereo delay. Its Audio Matrix offers MM (Mono), MS (MISO) and SS (Stereo) settings, and the audio connections are a TRS input and a TRS output. A Spread control sets the stereo width.
What power does the ZeroSum need?
The ZeroSum runs on 9V DC center negative and draws 145mA. That draw is higher than many single pedals take, so it is worth checking what your power supply can deliver on the outlet you plan to use.
Does the ZeroSum take an expression pedal?
Yes. There is an Expression CTRL jack on the rear panel, and Guitar Pedal X describes it as a multiplier running from x1 to x3, so an expression pedal can scale a parameter across that range while you play.
Sources (2)
- Guitar Pedal X, Guitar Pedal X, 2025-08-21
- Guitar Pedal X, Guitar Pedal X, 2025-12-10
