Radial ProD2: Two Passive DI Channels for Stereo Sources

The Radial ProD2 is a passive, transformer-isolated stereo direct box (DI), a two-channel passive DI box that is essentially two ProDIs built into a single chassis. Each channel takes a high-impedance instrument or line source, runs it through Radial's own Eclipse ET-DB2 transformer, and delivers a clean balanced output with no power required, while breaking the ground loops that cause hum. For anyone sending a stereo keyboard, synth, or DJ mixer to the front-of-house console, the ProD2 makes it clean, quiet, and effortless.

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 keyboard or mixer and drops it to the low impedance a console 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 that causes 60-cycle hum. The ProD2 does all three on two independent channels at once.

Passive vs Active: Why the ProD2 Needs No Power

The ProD2 is a passive DI, which means each channel uses a transformer rather than a powered buffer. A passive design needs no battery and no phantom power, and its transformers thrive on the hot, line-level signals a keyboard, synth, or DJ mixer produces: the more voltage they throw at it, the happier it is. An active DI is the better tool for delicate, low-output instrument pickups, but for strong stereo line sources the ProD2 delivers rich, natural tone with nothing to power and nothing to fail.

Two Channels, Two Eclipse Transformers

Inside the ProD2 sit two of Radial's Eclipse ET-DB2 transformers, one per channel, each with a 12:1 turns ratio that performs the impedance conversion and presents a 140 kilohm input. Both cores are wrapped in MuMETAL, a nickel-iron alloy that shields them from the stray magnetic fields thrown off by lighting dimmers and power amps, so both sides of your stereo image leave the box free of induced hum. With 128 dB of dynamic range on each channel, the ProD2 handles the hottest line output without a hint of strain.

Splitting Stereo: The 1/4-Inch Thru Jacks

The ProD2 gives you two balanced XLR outputs to send left and right to the console, and each channel also carries a 1/4-inch Thru jack. Those Thru jacks are the key to a clean stereo split: while the XLR outputs run the stereo pair to front of house, the Thru jacks pass the same signals on to a stage amp, a monitor rig, or a recorder. One keyboard can feed both the main console and your onstage monitoring at the same time, in full stereo, with no signal degradation.

Ground Lift and Pad, Per Channel

Every switch on the ProD2 is duplicated so you can treat each channel independently. Each side gets its own ground-lift switch to break the 60-cycle hum loop on that channel without affecting the other, and its own 15 dB pad to drop the level of a hot keyboard or mixer output so nothing overloads the transformer. That per-channel control means you can solve a hum problem on one side of a stereo rig while leaving the other side untouched.

On Keyboards, Synths, and DJ Mixers: Where the ProD2 Shines

This is the box's home turf. On a stereo keyboard or synth, the two channels capture the full left-right image and deliver it clean to the console. On a drum machine or sampler, the high headroom takes the punchiest programmed transients in stride. On a DJ mixer, the ProD2 turns the main outputs into a balanced, isolated feed the house engineer can trust. And with the Thru jacks, a keyboard can hit both front of house and stage monitors at once, stereo intact.

Who the ProD2 Is For

The ProD2 is for the keyboard player who runs a stereo rig and needs both sides to reach the console clean and hum-free; for the DJ who wants a bomb-proof, isolated stereo feed to the house system; and for the studio or stage tech splitting synths and samplers to front of house and monitors at the same time. If you have two channels of line-level audio that have to arrive clean and quiet, the ProD2 is the stereo passive direct box to standardize on.