
What is it?
Double-tracking has long been a studio technique to fatten up and widen your electric guitar sound, but an instant version of it has also been available in a select few dedicated pedals.
The latest of these is the KMA Machines Geminus, which uses a tweaked iteration of the double-tracking facility found in the company’s more complex Endgame, a pedal with IR cab and power amp simulation that’s designed to sit at the end of
your signal chain.
Double-tracking in the studio means recording the same part twice so you have two performances that can be panned apart in stereo to create a bigger sound, aided by the inevitable slight differences between the two performances.
What this pedal does is Automatic Double Tracking (ADT), giving the sense of two guitars playing by adding in a delayed – and possibly modulated – version as you play.
The Geminus has TRS input and output with three toggle-switched modes of operation, the ideal mode being a mono input and a stereo output emulating what traditionally happens in a studio. You can also run it as stereo in/stereo out or mono in/mono out.
Specs

- PRICE: $269/£199
- ORIGIN: Germany
- TYPE: Stereo double-tracking pedal
- FEATURES: Switchable True/Buffered Bypass, silent relay-based soft switching
- CONTROLS: TDT Width, Time, Level, Pitch switch, Stereo Mode switch, internal bypass selection dipswitch, bypass footswitch
- CONNECTIONS: Standard TRS input, standard TRS output
- POWER: 9V DC adaptor (not supplied) 100mA
- DIMENSIONS: 67 (w) x 123 (d) x 53mm (h)
- CONTACT: KMA Machines
Usability and sounds

What’s going on under the hood is AI-powered and impressively effective in the way it immediately delivers a rich spacious stereo sound from a single guitar: once you’ve heard it, you won’t want to turn the pedal off.
Three knobs have notched centre detent positions that give you expertly dialled-in tones straight out of the box, although there’s plenty of variation if you want it.
The large knob sets the width of the stereo field, while the Time knob adjusts the ‘tightness’ of the double-tracking, allowing a looser feel if desired, and the Level knob balances the volume of the doubled signal against the original source.

For more variation in the sound, you have the option of adding pitch modulation – a detuning in the doubled signal for more spaciousness, and a practical alternative to using a stereo chorus pedal, working particularly well on clean sounds.
While this is definitely a pedal that should be used with a stereo output, the Geminus is not redundant in mono as you can use it for slapback or chorus.
Verdict
Verdict: ★★★★½
Guitar World verdict: With a big sound in a compact footprint, the Geminus is an excellent, extremely easy-to-use pedal that’s not just for double-tracking but also for spacious stereo modulation.