The KMA Machines Active STEREO ABY is an active stereo / dual-mono ABY pedal with noise-free switching. It sends a stereo input to two separate stereo outputs, separately or combined, using regular 1/4 inch (6.35mm) jacks. Because the circuit is fully active, switching is silent, and the pedal can also run in either direction, splitting one signal into two or combining two into one1.
Controls
| Control | What it does |
|---|---|
| A&B>Y / Y>A&B switch | Allows for precise directionality, so the pedal can be used in either direction1 |
| Phase switch | Flips the A channel by 180 degrees, which can prevent signal cancellation and tone issues when combining or splitting signals, and helps to remove mismatches1 |
| LEDs | Red for A, Yellow for B, and Blue in the center for A&B1 |
The pedal sits in a durable compact enclosure that KMA describes as built for years of reliable switching1.
Power
The Active STEREO ABY runs on a 9V DC supply with a center negative 2.1mm plug and draws more than 55 mA at maximum1. Because it is a fully active design rather than a passive switcher, it needs power to operate at all, so a supply with headroom above that 55 mA figure is what the specification calls for.
Stereo versus mono: the Active ABY
KMA's ABY Series comes in two sizes of signal. The Active STEREO ABY is the stereo unit: it carries both sides of a stereo input to two separate stereo outputs, separately or combined1. Players who only need to work in mono are pointed instead to the KMA Machines Active ABY, the mono counterpart in the same series13. KMA's own framing of the pair is simple: "Need to work in Stereo? Then the KMA Active STEREO ABY is for you!"3
The Active STEREO ABY is an active Stereo / Dual-Mono ABY pedal with noise-free switching, built in a durable compact enclosure, with red, yellow and blue LEDs showing which output is engaged: red for A, yellow for B and blue in the center for A&B1.
Questions
Does the KMA Machines Active STEREO ABY need power?
Yes. It is a fully active design, so it runs on a 9V DC centre negative 2.1mm power supply and draws more than 55 mA at maximum. Because it is active rather than passive, it needs that power to switch silently, and a supply rated above 55 mA is the safe choice.
What does the phase switch do on the KMA Active STEREO ABY?
The Phase switch flips the A channel by 180 degrees. KMA Machines says this can prevent signal cancellation and tone issues that can appear when combining or splitting signals, helping to remove mismatches between the two paths.
Can the KMA Active STEREO ABY be used as both a splitter and a combiner?
Yes. An A&B>Y or Y>A&B switch allows for precise directionality, so the pedal can be used in either direction: one stereo input sent to two stereo outputs, or two sources combined into one. Outputs work via regular 1/4 inch (6.35mm) jacks.
What is the difference between the KMA Active ABY and the Active STEREO ABY?
The Active STEREO ABY handles stereo signals, sending a stereo input to two separate stereo outputs, separately or combined. The Active ABY is the mono counterpart in KMA's ABY Series, for players who only need to work in mono.
Where is the KMA Machines Active STEREO ABY made?
KMA Machines builds the Active STEREO ABY in Berlin, Germany. The pedal was announced in November 2025 as part of the company's new and improved Utility Switchers range.
Sources (3)
- Active STEREO ABY, KMA Machines
- Guitar Pedal X, Guitar Pedal X, 2025-11-18
- Active ABY, KMA Machines
