Radial Engineering JD-7

The JD-7 is currently the best tool available for re-amping a track or splitting one instrument (or line level) signal into multiple (up to seven) outputs. Usually I would wait until the end of a review to get to the conclusion, but the JD-7 is such a great box (and excellent value) that I couldn’t help myself.

First of all, the construction quality of the JD-7 is nothing less than superb for the asking price of $850. Constructed in Canada, the JD-7 is housed in a 14 gauge steel enclosure that is coated with super-heavy-duty baked enamel paint. While the heft of the enclosure is reassuring, the high quality parts (Jensen transformers throughout, discrete transistors based audio circuitry, and socketed IC chips) indicate right away that the designers of the J-7 elected to cut no corners.

The JD-7 is configured with two front panel ¼” inputs (input 2 has an optional 8 dB pad) allowing simultaneous connection of two instruments (though only one input is active) and one rear panel balanced XLR input with adjustable input level control. The front panel inputs include a rotary potentiometer (sans knob) labeled “drag” which varies the loading on the input source changing the “feel” of the input signals response. According to the manufacturer “The intention of the drag control is to reintroduce the natural loading that occurs when a guitar and an amplifier are connected together. This is not simply impedance matching, but we also compensating for the resistance in the amplifier circuit and the cable capacitance. The full-on clock-wise position essentially pulls the drag control out of the loop.”

The JD-7 has a total of eight outputs, six appearing on the front panel, and two on the back panel. The front panel outputs (all on ¼” jacks) are configured in the following way: output one is connected to ground and is used for connection to a “clean” amp and features an on/off pushbutton and indicator LED, outputs 2-4 are transformer isolated outputs which feature on/off pushbuttons, as well as ground lift and polarity reverse pushbuttons. Outputs 5 and 6 include the same features as 2-4 but they each include a switchable effects loop (with i/o’s on the back of the unit). The rear of the unit includes Output 7 which is a direct “always on” output (1/4” jack) ideal for connection to a tuner, and a Balanced line output appearing on a male XLR jack including polarity reversal and ground lift pushbuttons. A power-in jack (for the include wall-wart power supply) on a miniplug with retainer clip completes the rear panel i/o’s.

I used (and creatively misused!) the JD-7 in a variety of ways. First I compared it to my Radial JDI, their most basic direct box which consists of a Jensen JTBE transformer in a box with a pad and ground lift (interestingly the JD-7 uses the same Jensen transformer) using a Turner Renaissance bass guitar. I found the JD-7 to sound nearly identical which is impressive indeed considering the JDI is a passive audiophile quality unit and the JD-7 is an active unit with multiple outputs. If nothing else, the JD-7 makes a killer direct box!

Using my Tom Anderson Strat, I then connected the JD-7 to three amps (a vintage Fender Vibrolux, a Mesa Boogie Dual Rectifier, and a Bedrock 1200 head) and mic’d them, while at the same time sending a DI’ d signal directly to tape. Using the transformer coupled outputs (2-4) I encountered no untoward noises that couldn’t be eliminated with the front panel controls. I also sent output 5 direct into a Marshall 9001 tube preamp that I sent to tape as well. The advantage to distributing one signal to such a multitude of sources is that you can create huge stereo tracks without the need to double (or triple) track individual parts. This practice is a big part of producers such as Dave Jerden’s excellent guitar sounds.

Lastly I used the JD-7 to re-amp a couple of different tracks ranging from the direct guitar track I had just recorded, to a snare drum track that needed some real “room” tone, and a vocal track that I thought might sound good through a MXR stompbox compressor. Patching the JD-7 into the patchbay on my console, I was able to take these tracks and route them to varying destinations including guitar amps, PA system inputs, and stompboxes without impedance or ground loop problems. I had a blast, and got some great results!

The JD-7 provides the means for interfacing equipment in strange and wonderful ways leading to sonically interesting results. Overall the JD-7 is an absolute winner given its transparent sound, high parts quality, solid construction, and reasonable price.

Product Summary
Radial JD-7
Telephone – 604-942-1001
MSRP – $850