Radial AC-Driver Acoustic Instrument Preamp & DI Pedal

Radial AC-Driver: Studio-Grade Acoustic Tone in a Stage-Ready Preamp

The Radial AC-Driver is a compact acoustic instrument preamp and direct box, a pedal-format class-A FET preamp that takes the signal from an acoustic guitar pickup and shapes it into a warm, detailed, feedback-free tone ready for the PA. It combines a studio-quality buffer, a balanced XLR direct output, and the exact set of stage controls a performing acoustic player reaches for, all in a rugged 14-gauge steel housing that sits at your feet. For anyone who has plugged a beautiful acoustic guitar into a PA only to hear thin, brittle, feedback-prone sound, the AC-Driver is the box that finally makes the amplified instrument sound like the instrument.

Why Amplified Acoustic Guitars Sound Harsh

Most acoustic guitar pickups put out a weak, high-impedance signal that a standard mixer input was never designed to handle, so the tone loads down, thins out, and picks up noise on the cable run to front of house. Push that signal up in a loud room and the guitar's hollow body starts resonating with the stage volume, building the runaway howl of feedback. The AC-Driver addresses both problems at the source, buffering the pickup with a high-impedance class-A input and giving the player direct control over the frequencies and phase relationships that cause feedback in the first place.

Class-A FET Preamp With a PZ-Pre Voicing

At its core the AC-Driver uses a class-A FET audio circuit with a 10 megohm input impedance, high enough that a piezo or magnetic acoustic pickup sees no loading and delivers its full, natural tone. The preamp is voiced with a proprietary response curve modeled after Radial's flagship PZ-Pre, adding a warm yet detailed character that flatters most acoustic instruments, and it does so with a 107 dBu dynamic range and a noise floor down at -97 dBu. The signal that reaches the console is quiet, full, and unmistakably the sound of the guitar rather than the sound of a lesser input stage.

Two Tools to Stop Feedback: Notch and Phase

Feedback on an acoustic stage almost always spikes at one or two specific resonant frequencies, and the AC-Driver gives you a variable notch filter to hunt them down. Sweep the notch frequency knob until the ringing frequency drops out and the rest of the tone stays intact, surgically removing the problem instead of dulling the whole guitar. When feedback comes from broadband stage coupling instead, the 180-degree phase switch flips the guitar's polarity to cancel the hot spots that build it, and an adjustable low-cut filter clears out the boomy low frequencies that muddy a mix and feed subsonic rumble.

A Balanced DI Output Built Into the Preamp

Because the AC-Driver carries a balanced XLR output, it doubles as the direct box in the signal chain, sending a low-impedance balanced feed straight to the PA or a powered speaker with no separate DI required. A ground-lift switch on that output silences the hum and buzz of a ground loop between the stage and the console, and a level control sets the exact send to front of house. A separate 1/4-inch output can feed a stage amp at the same time, so the player hears themselves through a personal amp while the balanced DI drives the house.

Silent Tuning and Instrument Changes

A footswitchable mute is the detail that makes the AC-Driver a live performer's tool rather than just a preamp. Step on it to silence the output and the player can tune between songs in complete silence or swap to a second guitar without the thump and pop that hit the PA when a cable is pulled live. The whole unit is wrapped in a 14-gauge steel chassis that shrugs off the stomps, drops, and travel of a working stage, and it runs on standard 9-volt power.

Who the AC-Driver Is For

The AC-Driver is for the gigging singer-songwriter who wants a professional acoustic tone and a way to kill feedback without an engineer's help; for the worship or theater player who needs to change instruments silently mid-set; and for the touring acoustic act that wants one rugged box to preamp, shape, and direct-box the guitar to the PA. If your acoustic deserves better than a thin, howling signal through the house system, the AC-Driver is the preamp that delivers it.