Radial Pro48: The Active Phantom DI for Acoustic and Bass

The Radial Pro48 is an active, 48V phantom-powered direct box (DI), a compact single-channel active DI box that runs entirely on the phantom power your mixer already sends down the mic cable. It buffers a high-impedance instrument through a powered circuit, converts it to a clean balanced signal, and breaks the ground loops that put hum into an acoustic guitar or bass. For the player who wants the detail and clarity of an active DI in the simplest, most rugged package Radial builds, the Pro48 delivers it night after night.

What a DI Box Actually Does

A direct box does three jobs at once, and understanding them explains why you need one. First, impedance conversion: it takes the high-impedance output of a guitar or bass and drops it to the low impedance a mixer wants, so the tone stays full instead of thin. Second, it converts an unbalanced signal to a balanced one, so noise picked up along a long cable run cancels itself out and arrives clean. Third, it provides ground isolation, breaking the loop between your rig and the console that causes 60-cycle hum. The Pro48 does all three, cleanly and quietly.

Active vs Passive: Why the Pro48 Runs on Phantom Power

The Pro48 is an active DI, which means it uses a powered buffer rather than a transformer. That buffer presents a very high 220 kilohm input impedance, and that number matters: a high input impedance lets low-output active and passive pickups deliver their full detail instead of being loaded down and dulled. A passive DI is a fine tool for hot, high-level signals, but for the delicate output of an acoustic-electric pickup, the Pro48's powered front end preserves the clarity, attack, and natural body that a transformer alone can soften.

The Switching Power Supply: Headroom From Phantom Alone

Here is the engineering that sets the Pro48 apart from a battery-powered box. Rather than run on a 9V battery that dies mid-set, it uses an internal switching power supply that takes the 48V phantom from your mixer and converts it into a stable, high-headroom rail. That means clean, consistent performance for as long as phantom is present, with none of the sag, noise, or dead-battery panic that plagues lesser active boxes. Plug in, switch on phantom, and the Pro48 is ready.

A 220 Kilohm Input That Loves Low-Output Pickups

Input impedance is the specification that decides whether a pickup sounds full or thin. The Pro48's 220 kilohm input sits well above what a passive transformer can offer, so it does not load down a piezo or magnetic pickup the way a lower impedance would. The result is an acoustic guitar that keeps its sparkle and air, and a bass that keeps its attack and low-end weight, feeding a balanced 175 ohm output down the XLR to the console with a 20 Hz to 20 kHz response and vanishingly low 0.001 percent distortion.

Ground Lift and Pad: Simple, Rugged Control

The Pro48 keeps its control set deliberately lean so there is nothing to fuss with at showtime. A ground-lift switch breaks the 60-cycle hum loop between your rig and the mixer while phantom keeps feeding the active circuit. A 15 dB pad drops the input so the hottest active bass or line output cannot overload the buffer. A single LED confirms 48V is present so you always know the box is live, and a 1/4-inch Thru feeds an onstage amp while the XLR runs to front of house.

On Acoustic, Bass, and Low-Output Pickups: Where the Pro48 Shines

This is the box's home turf. On acoustic-electric guitar, the high input impedance is a perfect match for a piezo pickup, capturing the body and shimmer that make an acoustic sound real through a PA. On electric bass, active or passive, the powered buffer preserves attack and detail down a long hum-free run. On any instrument with a low-output pickup, the Pro48 delivers the signal to the console with clarity intact, whether you are on a worship stage, a club, or in the studio.

Who the Pro48 Is For

The Pro48 is for the singer-songwriter who plugs an acoustic-electric into the PA and needs it to sound natural and stay quiet; for the bassist who wants an active DI with the detail of a high-impedance input and the reliability of phantom power; and for the worship or club tech who needs a simple, bomb-proof active box that just works. If you play a low-output pickup and the signal has to reach the console clean and hum-free, the Pro48 is the active direct box to reach for.