The Radial ProDI is a high-quality passive mono direct box designed for acoustic guitars, bass guitars, electric pianos, and synthesizers. Its custom transformer ensures top-tier performance with minimal noise. Like all Radial DI boxes, the ProDI is extremely durable and simple to operate — just plug in your mono instrument and instantly remove ground loops while enjoying a full, rich sound. For stereo applications, Radial also offers the ProD2 stereo version.
The Radial ProDI and ProD2 are full-range passive direct boxes. Active DIs use electronic circuits to convert hi-Z to lo-Z signals and require power from batteries, phantom power, or external supplies. Passive DIs rely solely on a transformer, needing no power to operate. The transformer design also excels at reducing system noise, making the ProDI and ProD2 excellent noise-eliminating tools thanks to their high-quality transformers.
Equipped with a custom-made transformer, the ProDI delivers exceptional signal handling without saturation and maintains extremely low phase distortion in crucial bass and mid frequencies. The transformer provides 100% isolation to remove hum- and noise-causing ground loops while preserving sonic integrity. Additional features include isolated XLR connectors to prevent chassis ground issues and a military-spec PC board with a full ground plane to reduce RF noise. The result is outstanding clarity and definition at an affordable price.
The ProDI is a true plug-and-play device: connect your instrument to the 1/4" input, the 1/4" thru to your amplifier or mixer, and the XLR output to the console — that's it. Experiencing distortion? Use the -15dB pad. Hearing noise? Engage the ground-lift switch. Acoustic and bass instruments retain their natural tone with smooth, musical results, while powered devices like keyboards benefit from ground-loop elimination and enhanced dynamics.
Inside the ProDI you’ll find Radial’s uncompromising build quality, designed for years of professional use. Its unique “book cover” design protects switches and connectors, while the 14-gauge welded I-beam chassis prevents torque stress that can damage circuit boards. This significantly reduces failures caused by broken solder joints, especially in demanding environments like rental or touring use. A full-bottom no-slip rubber pad increases electrical isolation and keeps the DI firmly in place on stage.
The ProDI is a passive direct box built for stage use and home studios, capable of handling high-output instruments without distortion. Its transformer-isolated output eliminates noise caused by ground loops, ensuring clean, reliable signal transfer in any environment.
At the core of the ProDI is a custom-wound Radial transformer featuring an exceptionally high 140kΩ input impedance to minimize loading. This allows the ProDI to handle extreme signal levels across the entire frequency range without distortion. An internal MuMETAL® shield further protects the transformer from electromagnetic fields that can cause noise or unwanted coloration.
The ProDI performs exceptionally well with high-output instruments such as active bass guitars. It easily manages the powerful signal levels from active pickups without distortion, while the transformer isolation eliminates ground-loop hum. The result is a clean, accurate bass signal sent both to the PA system and the player’s amplifier.
Active acoustic guitar preamps can sometimes sound harsh or overly sharp. The ProDI naturally smooths transients for a warmer, more musical tone. Because it can handle strong signals from active pickups without distorting, it is an excellent direct box choice for acoustic guitar performers.
Modern digital keyboards produce extremely dynamic signals with a wide frequency range. The ProDI can withstand high signal levels at all frequencies without introducing distortion or phase shift. This ensures every patch — from deep basses to sparkling highs — sounds clean, full, and accurate.
