[review] Spaceman Mercury III - Harmonic Boost (by LordRiffenstein)

LordRiffenstein, all-around tone freak and purveyor of great tone.


Spaceman is based in Portland, OR. They are a small company and hand-building their pedals using quality components.  Each pedal is built as a limited edition so you have to get them when they are available. Their current range has a boost, drive and fuzz pedal but that can change quickly.

Mercury III

So here is a boost pedal with 3 controls which you might think is too much but you’d be wrong! Boost sets the output level and there is plenty on tap. On the right side you will find a rotary control offering 6 different tone selections. The middle control is the one makes this pedal stand out.  The Mercury III adds even-order harmonics to your original signal and the Harmonics control sets the amount. Build quality is excellent as always with Spaceman Effects pedals!!

Spaceman Mercury IIIThe pedal in use

After reviewing their Aphelion, I had a good idea what fun Spaceman Effects can provide with harmonics-pushing pedals. So I was interested what they could do with this concept in a boost pedal.

Let me start with the 6-position tone control!  It works really well but it is not your typical tone control.  It works closely together with the Boost and Harmonics controls. The 6 positions vary between full/mid/treble/bass boost, just try the different positions and listen to what works best for your application. The Boost control has plenty of level, I had no issues driving a low crunch setting into a big fat rock tone.

Spaceman Mercury IIIThe Harmonics control is the one for the extra fun. With the control OFF, it is not adding any harmonics and you have a clean boost, which also sounds really nice. Adding harmonics changes things a lot and I was very pleasantly surprised with this pedal. Plug into a crunchy amp and with a healthy amount of boost going, you can get all sorts of tones riding your guitar’s controls. Put this pedal in front of a touch responsive amp and you could do an entire gig with it.  I tried it in front of a number of amps and it never failed to amaze!!

For obvious reasons, it works best in front of low to medium gain settings but even when applied to high gain tones, the Mercury III can bring some new life to your tone. The combinations of the 3 controls are plenty but they take some time to learn.  It’s not hard to tweak once you have got to know it and I’m pretty sure this is not a set-and-forget-pedal.

The Mercury III is another homerun in my opinion. The idea behind it is very simple and it just works really well. As you can use it with or without adding the harmonics, you get 2 pedals in 1 and a lot of great tones in a stellar box!!!

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