A cut above other acoustic pre-amps
This is an expensive unit, but I finally feel like I've finally found something that really translates pure acoustic tone from my guitars. I'm a real tone bug and have high end acoustic guitars. I use K&K Pure Mini's on all my guitars-- mostly because they are a non-invasive install that an be easily removed (no permanent alteration to the instruments). As such, this review only relates to how the Grace unit interacts with K&K passive pickups.
K&K pickups can sound really good, but they have an impedance and construction that (to my ear) doesn't like a whole lot of the acoustic pre-amps out on the market (including K&K's own pre-amps-sad to say). In fact, my recommendation is that, if you can't afford this unit, a simple Boss 7-band EQ pedal is your next best bet with K&Ks (cut a lot of low mids using the Boss EQ and you get into the ballpark for a decent acoustic sound). I've discarded or sold off more acoustic pre-amps than I care to admit, but that "never-ending quest" for good acoustic sound from a pickup is now over with ---thanks to the Grace ALiX.
From the get-go, the Grace ALiX sounded infinitely better than any other acoustic pre-amp I've tried--even before I began making adjustments. There was a quiet "roundness" and smoothness to its sound that is similar to that of a great old classic analog mixing board channel. Screams "high quality" design. I found, for my K&Ks, the primary "low-mid dump" typically necessary get rid of pickup muddiness is best achieved using the notch filter, dialed at about 800k (or the 3:30 o'clock to use a clock comparison). I actually would have liked to reserve that dial for use as a high pass roll-off (it can be used as either), but I found I needed to use the notch filter to "ground" the sound before finessing things further with the fully parametric mid EQ. Oddly, I ended up setting the parametric mid to boost highs/hi-mids a bit at what looks to be the 5k position, with the "Q" factor dialed all the way down (affecting a broad spectrum of frequencies) and the mid gain dial at 2 o'clock. I really expected to be more "surgical" with the fully parametric mids and using them to sculpt out quacky or tinny mids, but that's where I found the best sound. Highs were set at 2 o'clock position and lows dialed down to about 10:30. Master gain at 11:00 o'clock. It sounds fantastic and natural! I doubt I will get much benefit from supplementing my pickup with a condenser mic-which I often do. What will I find to grumble about now that my pickup sound issues are laid to rest!!
A couple tips. You will have to find a short TRS insert cord if you want to keep things neat on your pedalboard and integrate effects. These cords are hard to find. I ended up first reconfiguring my pedalboard around the ALiX and then ordering a custom length TRS insert cord to avoid creating a crow's nest of extra cable on the pedalboard. Also, the tuner output is dependent on the "amp out" dial being turned up (a "Duh" moment till I realized this). Mute footswitch for tuning is dead silent (as should be on an expensive unit).
Kudos to the Grace Design folks for putting out a quality product that for me was a real game changer in terms of achieving true acoustic guitar sound. The first time I used live it the club owner (a talented musician) wanted to know what kind of acoustic guitar I had --as it was "the best sounding guitar he'd ever heard in his club." I told him "it's this here box" and pointed to the Grace ALiX.