Radial ProD8 8-Channel Passive Rackmount DI Direct Box

Radial ProD8: Eight Channels of Passive DI in a Single Rack Space

The Radial ProD8 is a passive, transformer-isolated 8-channel rackmount direct box (DI), a 1U rack unit that puts eight independent DI channels behind a keyboard rig without drawing a single watt of power. Each channel runs a high-impedance instrument or line source through a custom-wound Eclipse ET-DB2 transformer, converting it to a clean, balanced, low-noise feed while breaking the ground loops that put hum in a stage full of synths. For the touring keyboardist or system tech who has to get a dozen sound sources to front of house cleanly and reliably, the ProD8 turns a tangle of cables into one tidy, bulletproof rack.

Why a Rackmount DI Changes How You Wire a Keyboard Rig

A single keyboard player on a modern stage can carry three, four, or more sound sources, and every one of them needs a direct box to reach the console cleanly. Wiring that with individual DI boxes means a floor covered in loose stomp-boxes and a rat's nest of cables that a stagehand can kick loose mid-show. The ProD8 collapses all of that into one rackmount unit: eight channels bolted into the same rack as the keyboards, patched once, and rolled on and off stage as a single trusted system. Set it up once and the whole rig is ready every night.

Passive by Design: Transformer Saturation Instead of Clipping

The ProD8 is fully passive, meaning each channel uses a transformer rather than a powered active buffer, so it needs no battery and no phantom power to work. That matters more than convenience with digital keyboards, which throw hot, high-level signals that can overload a lesser box. When an active circuit runs out of rail voltage it clips, squaring off the waveform into harsh distortion. A transformer instead saturates gently, rounding the tone into a warm Bessel curve reminiscent of the finest vintage audio gear. The ProD8 takes the hottest synth patch in stride and makes it sound better for the effort.

Inside: Eight Eclipse ET-DB2 Transformers and 100% Galvanic Isolation

The engine in every ProD8 channel is a custom-wound Eclipse ET-DB2 transformer with a 12:1 turns ratio that performs both the impedance conversion and the balancing at once, presenting a 140 kilohm input and delivering a 150 ohm balanced output that stays linear from 20 Hz to 18.5 kHz. Just as important, the transformer provides 100 percent galvanic isolation between the source and the console, physically breaking the electrical path that causes ground-loop hum and buzz. With 128 dB of dynamic range and a maximum input of +18 dB per channel, there is headroom to spare on even the punchiest programmed material.

Dual Inputs Per Channel: Backup Rigs and 16-Source Summing

Each of the eight channels carries two 1/4-inch inputs, and that redundancy is a working musician's insurance policy. Run a main keyboard into one input and a backup instrument into the other, and if a unit fails mid-set you switch sources without re-patching a thing. The same dual inputs also sum two sources into one channel, so a full ProD8 can accept up to 16 lines of audio at once, ideal for running two multitrack players in sync for backing tracks or combining redundant keyboard setups into a single console feed.

Effects Inserts, Thru-Puts, and Per-Channel Front-Panel Control

The ProD8 is built for real signal routing, not just a straight pass-through. Every channel includes a 1/4-inch TRS effects insert for patching in an outboard processor, plus a thru-put jack that sends a direct feed back to the artist's own playback or stage amp. On the front panel, each of the eight isolated XLR outputs carries its own ground-lift switch to silence hum on that channel independently, and its own 180-degree polarity-reverse switch to lock phase with a mic or another source. You get channel-by-channel control over the entire rig from one panel.

Reversible Rack Ears for Front or Rear Patching

Radial fits the ProD8 with reversible rack ears so the unit adapts to how a rig is actually wired. Mount it with the 1/4-inch inputs facing the front of the rack when you are patching external keyboards on the fly, so the system tech has instant access to inputs and thru-puts. Flip the ears and set the XLR outputs facing front instead, and a touring rack of modular synths stays permanently connected inside while the sound crew patches only the XLR outs into the main snake. One box, two workflows, no compromise.

Who the ProD8 Is For

The ProD8 is for the touring keyboardist who carries a rack of synths and needs every one of them to reach front of house cleanly and hum-free; for the system tech wiring a professional stage who wants eight isolated DI channels bolted into one rack instead of scattered across the floor; and for the playback engineer running backing tracks who needs redundant, summable inputs that never fail. If you send multiple high-output keyboard or line sources to a console night after night, the ProD8 is the rackmount direct box to build the rig around.