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Mooer Audio Yellow Comp Review

Mooer Audio Yellow Comp Review

Diminutive compressor delivers quiet, transparent performance.

Mooer Audio excels at big tone in very small packages. Better still, their ever-growing line of virtually microscopic stompboxes is super-affordable. The Yellow Comp, the second compressor in their Micro Pedal series, offers smooth optical compression via simple analog circuitry in a pocket-sized package.

The Little Compressor That Could
The Yellow Comp’s circuitry is packed into a tiny 3 1/2" x 1 1/4" x 1 1/4" enclosure. That’s small enough to conceal with a fist. The only downsides to the diminutive design are a slender, top-heavy configuration that all but necessitates Velcro, and the fact that the housing is too small to fit a battery inside. (It can only be powered by 9-volt Boss-style power sources.)

I not only heard added fullness, but could also feel each note decay in a smoother and more natural-sounding way.

The pedal’s optical circuit uses tiny photosensitive resistors that react to a small LED that glows brighter the stronger you pick. Some feel that optical compressors provide more dynamic and transparent compression than comparable IC and FET-based circuits. Three controls adjust volume, compression ratio and brightness. These minimal controls can handle most situations, though they might not offer enough fine-tuning for players who feel they need to adjust a compressors sustain, attack, or release controls.

Mellow Yellow
With a Stratocaster and Twin Reverb and the Mooer’s EQ and Comp controls set to noon, the Yellow adds a very subtle compression better described as tone enhancement than an “effect.” The transparency and lack of added coloration is great for beefing up an essentially excellent tone recipe like the Stratocaster and Twin. I not only heard added fullness, but could also feel each note decay in a smoother and more natural-sounding way.


Small footprint. Quiet and transparent. Reasonable price.

Can’t adjust attack and release. No battery option.


Ease of Use:




Mooer Audio Yellow Compressor

Players lamenting the absence of attack and release controls should note that Mooer did an excellent job tweaking the circuit to prevent the “quack” many compressors produce from harder picking (and which you can usually dial back with the help of those two controls).

Next to its crystal-clear tonality, the Yellow Comp’s finest asset is its fantastic EQ control. It responds like most single-band tone controls: sweeping between bass-heavy compression and accentuated treble. Midrange remains intact and natural sounding, no matter where the control is set. This was useful when I placed the pedal in front of an early Fulltone OCD overdrive pedal, a version known for its somewhat scooped midrange relative to later versions. After setting the OCD to mild overdrive and boosting mids via the Twin’s EQ, I could use the Yellow Comp as a volume booster to goose the OCD’s input for a richer, more fluid overdrive. And with the Comp’s EQ control, I could thicken the high end without losing any midrange detail.

The Verdict
The pint-sized Yellow Comp is an affordable, impressive-sounding optical compressor. If you’re a country guitarist who likes the coloration and pumping, in-your-face sound of IC -based compressors like the MXR Dyna Comp and Ross Compressor, the Yellow Comp’s extreme transparency might be a turn-off. But if transparency is your goal, you’ll find many uses for the Yellow Comp.