The controls include a 3-position Boost switch, which in position 2 increases gain by defeating the Treble and Bass controls, while attenuating the lows slightly for a more focused distortion sound. Position 3 kicks this theme up another notch by increasing the gain from the tone stack and reverb, and further tailoring the low-end to match. It’s worth noting that the Cut switch—which works like a reverse bright switch to roll off highs—can be used in conjunction with any of the Boost switch settings.
Another standout function is the 4-position attenuator, which lets you set the amp’s output at 8, 2, 2, or 1/10 watts. The first two settings saw the most action in our tests (two watts is perfect for practice or recording), while the 1/10-watt setting is so quiet that it’s probably only useful for those times when you want to wail in the living room without waking the baby. The Mercury’s spring reverb is extremely cool, offering everything from sublime airy washes to soaking wet surf textures.
With the Volume turned down to around nine o’clock and the Boost switch on 1, the Mercury’s clean tones are warm and inviting, with a nice crisp edge that brings welcome definition to chords and jazzy lead lines. If you want to add a touch of grit, just click the Boost to the second position. This is a very organic way of putting a little hair on your clean sounds, and slight upward adjustments of the Volume knob will take you straight to the old-school blues zone. Put the Boost on 3 and the distortion goes up significantly, and the midrange gets noticeably punchier—great for solos.
The Mercury also delivers excellent higher-gain tones, and with the Volume cranked up to around two o’clock with the Boost on 2, you get muscular, throaty distortion that’s delivered in all its glory by the Kingpin 60 speaker. Further tweaks of the Boost and Volume controls send the Mercury into maximum overdrive—which is still relatively moderate—at volumes that could cut it on a small stage. You can run the Mercury flat out without any loss of sonic integrity, and that EL34 definitely packs some punch, even though it’s throttled back to a quarter of its output potential in this amp. All considered, and three years after its introduction, the Mercury is still on the cutting edge of small amp design, and it’s one of the best choices around for lower volume applications.