Review: Grace Design’s MOXi, a Two-Channel Instrument Preamp, Offers Pristine Sound and Streamlined Features

For acoustic performers who use more than one instrument, or amplify a guitar with a dual-source system, the prospect of having a preamp with multiple channels is very attractive: fewer pieces of gear at your feet, and more control over your sound. 

Among touring pros, Grace Design’s FELiX preamp has long been a favored two-channel option, but the FELiX comes with a hefty price tag (north of $1,300) and a lot of complexity. Enter Grace’s MOXi, a preamp/blender with a much simpler feature set, smaller footprint (about 7 by 4 inches), and lower price ($680 street) that still delivers the studio-quality sound the company is known for.

Released in 2025, MOXi offers independent controls on the two channels for gain, high-pass filter, and three-band EQ (including sweepable midrange, which BiX, MOXi’s single-channel sibling, does not have). Both channels also have phase reverse switches and can provide 6-volt power sufficient for small instrument-mounted mics. Toggle between channels with a footswitch, or change the setting on the back to blend the two. A second footswitch is for boost (up to 10 dB), and a third mutes the output for tuning or unplugging.

For dual-source amplification systems, you can plug in a single TRS cable and send the sources to separate channels. There’s an effects loop and an amp/line out in addition to the XLR output. 

I had the chance to try out MOXi in a variety of gigs. Often I’m switching between a Collings OM2H Cut (with a K&K Pure Mini pickup) and a Strumstick, and the MOXi made it a snap to balance their levels and EQ—no tweaking necessary from the engineer. The sound was super clean and clear on both instruments, and easy to adjust. I used the effects out to add a Boss tuner pedal, and dialed in the boost for solos when playing with a band. 

With my guitars equipped with Fishman Rare Earth Blend systems, I sent the magnetic pickup and internal mic to separate channels on MOXi. I appreciated the ability to set their gain and EQ independently—especially useful for the sensitive mic signal—and then control the mix.

For me, MOXi hits the spot—handling two-instrument and dual-source setups without overwhelming me with knobs and options. It’s a rugged, reliable, and superb-sounding preamp with all the essentials for high-fidelity acoustic amplification. gracedesign.com