Review: Tech 21 Acoustic Fly Rig

This rig-replacing ultra-portable pedal offers offers essential tones, tools, and effects for acoustic guitarists.

In 1989, a decade or so before the arrival of the first digitally modeled amps and effects, Tech 21’s Andrew Barta introduced the analog SansAmp tube amp emulator. This pocket-sized provider of tube-like tone facilitated plugging electric guitars into mixers for amp-free direct recording or performance. The latest deployment of the now-seasoned SansAmp is the Acoustic Fly Rig, a five-button featherweight that lets you plug your acoustic guitar direct into a PA mixer, recording console, or computer recording setup. You can also use it with an amp, either plugging straight into the input as you would any effects pedal, or into the amp’s effects return to bypass its preamp section. Further, the Acoustic Fly Rig offers essential tools and bonus effects tailored to the amplified acoustic player.

The Acoustic Fly Rig is the newest of Tech 21’s Fly Rig series, which is based on the notion that if you’re called on a fly-away studio or performance gig, you’d only have to pack your axe and this sprightly stompbox, which weighs in at a slim 1.3 pounds. At 12-1/2 inches long, there’s a decent chance the Acoustic Fly Rig will fit in your gig bag pocket. Once set up, the Acoustic Fly Rig acts like a souped-up DI or acoustic preamp, delivering a high-quality, low-impedance signal that’s ready to be plugged into a mixer channel and drive longer cable runs without degradation. On top of that, there’s a compressor, a boost function, a powerful 3-band EQ with sweepable mids, reverb, and chorus or delay with tap-tempo time control. And of course, there’s the tuner/mute, whose importance can’t be overstated. For controlling feedback, there’s a phase flip switch and a notch filter knob, sweepable from 70Hz to 350Hz to help tame wild rumbles. A sweepable low-pass filter (LPF) rolls off unwanted top-end frequencies and artifacts.


The Acoustic Fly Rig comes in a handsome rectangular tin, which makes for a pretty sweet unboxing experience. It’s powered by an AC adapter, so you may want to throw a power strip into your carry-on, too. Our tester was an appealing burnt orange with a shiny metal finish that sometimes made it difficult to make out button labels when the unit was on the floor, but it wasn’t really a problem once I got used to the footswitch functions. Tech 21’s custom footswitch actuators feel firm and springy, with no audible click. In addition to the footswitches, there are rugged rubber push-button toggles for settings you won’t need to step on mid-performance, like ground lift for the XLR output, phase flip, and some of the effect settings. Small, sturdy, translucent knobs line up across the top, each illuminating in section-specific colors to indicate when that section or function is engaged. The blue knob on the left, E.Level, doubles as a clip warning, flashing red when the unit is overloaded. Like most stompboxes, the 1/4-inch input is on the right, with 1/4-inch and XLR outputs at left.


Accordingly, you can follow the signal chain from right to left. It starts with phase flip, which combats feedback by reversing the output signal so it’s out of phase with the input signal. Next are the compressor (COMP) and boost, both of which have dedicated footswitches. For the compressor, Tech 21 chose analog, FET-based circuitry for warmth and transparency. You could crank up the compression control for a squashed, sustain-heavy sound, but I liked dialing in just enough to keep loud strumming tight and controlled and make fingerpicking pop. A level control sets the compressor’s output. It’s pretty sensitive, so I kept it below 12 o’clock to avoid feedback, and kicked in the boost button to stand out during solos. The variable boost control lets you set just how much you want to show off, up to 12dB.

The SansAmp section is the heart of the Fly Rig. You can disengage it with a push button, but keep it on for plugging in direct to PA and recording mixers. It’s nice that Tech 21 included the option of turning the SansAmp off, but keeping it on has another advantage: That’s where the robust EQ and filters are. My main guitar for singer-songwriter performances is equipped with an L.R. Baggs Lyric pickup, which captures the instrument’s prominent, baritone-like lows, crisp top end, and relatively scooped mids. I routed it through the Fly Rig into a mixer and a loud powered PA speaker. The Fly Rig ’s EQ section was tremendously helpful in balancing out the guitar’s conspicuous bottom; I gently cut lows and swept the midrange EQ to emphasize a sweet spot, then boosted the highs a smidge for better articulation. The guitar’s voice boldly came through without overpowering the room, while still leaving plenty of hi-mid sonic space for my tenor voice. When I turned up the PA, the notch filter helped bridle emerging feedback. With this guitar, I kept the low-pass filter set fairly high, but I cut it back a bit when strumming a brighter, janglier acoustic, which also benefited from light compression.

The middle footswitch turns on reverb, which is next in the signal chain. You can choose between small room and large hall reverbs, and there’s a dedicated knob for dialing in the reverb amount. The larger setting had a big, spacious sound with audible echoing reflections when the reverb knob was dimed. My favorite recipe was the small room with reverb set straight up at 12 o’clock. This gave me a sound so warm and natural that I almost forgot it was on—until I turned it off.

The digital effects section, or EFX, is last in the signal flow, presenting a toggle choice of chorus or delay. You can turn effects on or off with the second footswitch from the left. Aside from the effects level knob (E.Level), the chorus effect has no controls—so don’t expect to concoct wild waves of modulation. Instead, it offers a single shimmery sound that’s useful and very pleasant, if a tad subtle. It sounded a bit like two guitars, or a 12-string guitar blended with a six-string. The delay effect yields a much greater variety of sounds, owing to the knobs that set delay time and the number of repeats. The delay time, which helpfully can also be set by tapping the tempo on the far left footswitch, can range from a doubled sound or rockabilly slapback to a delay of about a second. Repeats can go from a single echo to what initially seem like infinite resonant clones, but they eventually start to fade. For both effects, E.Level sets how much the effect is blended in with the clean signal.

There are a couple more useful features: Hold down the final footswitch to mute the signal and turn on the tuner, which has a very easy-to-read display. The 1/4-inch output jack doubles as a headphone jack; just mash the headphone button and the output gets louder and drives both sides. Just don’t use the headphone setting when plugged into a mixer!


Overall, the Acoustic Fly Rig is a terrific tool for acoustic guitarists. It’s well built, it operates extremely quietly, it has potent EQ and effects, and it has a few things that every amplified acoustic player needs—like feedback-controlling features and a tuner/mute. All that, plus it’s extremely portable, and much easier to carry than an amp. Though I boarded no planes during my time with the Acoustic Fly Rig , I definitely felt like I was flying in friendly sonic skies. 

Tech 21 Acoustic Fly Rig

KEY FEATURES Sweepable, semi-parametric active EQ controls; compression, reverb, delay, and chorus effects; chromatic tuner; anti-feedback control; 1/4″ input and output; XLR output with ground lift; 9-volt DC power supply (included)

PRICE $299 street



This article originally appeared in the May 2018 issue of Acoustic Guitar magazine.

Bill Leigh
Bill Leigh

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