Grace Design MOXi

A new two-channel acoustic instrument preamp from Colorado’s studio gear specialists.

June 26, 2025

Based in Lyons, Colorado, Grace Design was already a major player in the world of high-end mic preamps and studio gear when it released its FELiX acoustic-instrument preamp about a decade ago (check out our demo!). Run by brothers Michael and Eben Grace, the award-winning company was founded in the early 1990s, and it has built a reputation for great sound and solid construction. Grace entered the acoustic amplification market at the high-end with the FELiX, which offered high-grade components, rugged construction, and just about every feature imaginable. Despite a street price of about $1,250, the unit was immediately embraced by pro performers and has since become a classic. Grace followed that success with a pair of single-channel preamps, the ALiX and BiX. The company is rounding out its offerings with the MOXi, a two-channel preamp that is simpler, smaller, and more affordable than the FELiX. In this video, I demo the unit in the Peghead Nation studio.

With a footprint of about 7 x 4 inches, the MOXi helps streamline crammed pedalboards, and its standard nine-volt power requirement makes it easier to integrate with existing pedal power supplies than the FELiX’s dedicated AC-power. The MOXi has two identical channels, each featuring a gain control, high pass filter, and three-band EQ with tunable mids. Three foot switches allow channel switching, signal boosting, and output muting. The rear-panel has a pair of ¼-inch inputs, with the channel two jack configured as TRS (tip, ring, sleeve), making it compatible with stereo cables for dual-pickup setups. Each channel can supply 12 volts of phantom power and includes a phase-reverse button. There are also ¼-inch jacks for amp output and effects send and return. Finally, the unit has a balanced XLR DI output and a ground lift button.

In the video, I demo the MOXi using a Martin OM with an L.R. Baggs Anthem SL pickup system and a Fishman SA330x mini PA. At home, I also tried it with a Kenny Hill classical guitar with a Fishman Acoustic Matrix and a Larrivée Parlor with a Seymour Duncan MagMic. Even before firing up the MOXi, I was impressed with its solid, durable construction. The gain knobs have continuous ratchet-style detents that make them resist accidental movement, the low, mid, and high knobs feature center-detents, and all the pots move smoothly. Clear numbers and high contrast between the knobs and housing make it easy to see settings, even from a distance or in poor light.

The satisfaction continued once I plugged in and turned up the volume: Whether I was using the amp output to drive my AER Compact 60 at home or the Fishman SA330x, the sound was undeniably fat and ultra-clean. With active pickups in my guitars, setting the gain between about 9 and 11 o’clock gave me enough output signal without overdriving the preamp, and there was plenty of headroom to give weaker passive pickups a boost. The MOXi’s EQ setup is intuitive and apt for use with acoustic instrument pickups. While the low and high controls don’t have as big a range as some, they offered just the right tonal qualities to cut or boost bass and treble frequencies with the pickups I used to test them. Having tunable mids is often the key to dialing in a natural acoustic sound, eliminating troublesome frequencies, and shaping a particular tone. The MOXi’s two mid controls allowed me to sweep through the spectrum and reduce or boost accordingly. I only used one channel with my particular setup, but having two independent channels is useful for dual-pickup systems or for plugging in two instruments into the same box and switching between the separate settings with the A/B selector footswitch.

With its friendly, stripped-down design and remarkable set of features, the MOXi was obviously designed by folks with practical experience of amplifying acoustic instruments. The unit’s straight-forward operation, ultra-clean sound, and musical EQ make it a joy to use, and I’m sure that it will find as many fans as its siblings in the Grace instrument preamp family.

Grace Design MOXi

Two-channel preamp/EQ/Direct Box for acoustic-electric instruments
2 ¼-inch inputs (TRS on channel 2) with phase inversion switches
XLR DI output with ground-lift
¼-inch Amp output
¼-inch effect loop send and returns
3-band EQ with tunable midrange on each channel
High pass filter on each channel
Mix control for blending between channels
Mini dip switches for mix modes, channel 1 boost “off,” and optional 12-volt mic power on each channel.
Footswitches for A/B switching, Boost (with level control), and Mute
Metal enclosure
External nine-volt power
$720 list/$649 street