Radial JD-7 Injector

Radial Engineering’s JD-7 Injector guitar-signal distribution amp and router takes the direct box to another level, allowing you to route a guitar or bass signal to as many as seven different amps or amp simulators without ground loops or phase problems. In addition, you can reamp: record your instrument direct, then route the recorded track through the JD-7’s line-level inputs and route them to multiple miked guitar amplifiers.
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Radial Engineering's JD-7 Injector guitar-signal distribution amp and router ($850) takes the direct box to another level, allowing you to route a guitar or bass signal to as many as seven different amps or amp simulators without ground loops or phase problems. You can also record your instrument direct, then route the recorded track through the JD-7's line-level inputs and route them to multiple miked guitar amplifiers. This technique, known as reamping, is a hot ticket nowadays, because you can record the guitar parts dry and sweat the amp sound later.

Getting There from Here

The JD-7 is a 1-in, 7-out splitter/router. Two front-panel ¼-inch inputs allow simultaneous connection of two instruments; a button selects the active input. Input B has a defeatable 8 dB pad. You also get a clip LED.

Line-level, ¼-inch outputs 1 through 6 are on the front panel; output 7 is on the rear. Channel 1 is an active, direct out and is used for connection to a “clean” amp. It features an on/off button and an indicator LED. The other five front-panel outputs are transformer isolated and feature on/off, ground-lift, and polarity-reverse buttons. Outputs 5 and 6 also include an effects loop that can be switched for wet/dry comparisons; the send and return jacks are on the back of the unit. Rear-panel output 7 is a ¼-inch, active, direct, “always on” output — ideal for connection to a tuner or rack effects.

The rear panel also sports a balanced direct output on a male XLR jack (with polarity reversal and ground lift) and a balanced XLR input with level control. These are not alternatives to the ¼-inch I/O; the balanced output is designed to send a dry, low-impedance signal to a recording device, and the balanced input allows you to return a track from the recorder to the JD-7 for routing.

A power jack for the included wall-wart power supply completes the rear-panel connections. A retainer clip provides stress relief for the power cable.

The construction quality of the JD-7 is nothing less than superb, especially considering the asking price of $850. The heft of the enclosure is reassuring, and the high-quality Jensen transformers, discrete Class A audio circuitry, and socketed IC chips clearly indicate that the designers cut no corners. Note that no op amps or ICs are in the signal path; Radial's objective is to create a sonically transparent splitter/router so that the guitar's pure sound is preserved. To my ears, the company has met this goal.

Drag Your Axe

The Drag feature, controlled using a rotary potentiometer (sans knob), varies the loading on the input source, changing the feel of the input signal's response. According to the manufacturer, Drag emulates the natural loading that occurs when a guitar and an amplifier are connected together.

In addition to impedance matching, Radial has compensated for the resistance in the amplifier circuit, as well as the cable capacitance. Drag is essentially turned off when the control is turned fully clockwise.

Sound Tests

I used and creatively misused the JD-7 in a variety of ways. Using a Turner Renaissance bass guitar, I compared the new unit to a Radial JDI, the company's most basic direct box, which consists of the same Jensen JTBE transformer found in the JD7, a pad, and ground lift. The two units sounded nearly identical, which is particularly impressive considering that the JDI is a passive, audiophile-quality unit, while the JD-7 is an active unit with multiple outputs.

I then connected my Strat through the JD-7 to three miked amps while at the same time sending a signal directly to tape through a direct box. Using outputs 2 to 4, I encountered no untoward noises that couldn't be eliminated with the controls. I also sent output 5 direct into a tube preamp and printed that to tape. That let me create huge stereo tracks without the need to double- or triple-track individual parts.

Finally, I used the JD-7 to reamp several tracks, including a snare track that needed some real room tone and a vocal track that I thought might sound good through an MXR stompbox compressor. I had a blast and got some great results.

Injecting My Opinion

The JD-7 lets you interface equipment in strange and wonderful ways, leading to sonically interesting results. I'm not thrilled with the wall-wart power supply, and I would have appreciated level controls for the individual outputs, but these are quibbles, and good arguments could be made for leaving out these features. Given its transparent sound, high-quality parts, and solid construction, the JD-7 is the best tool available for reamping a track or splitting an instrument- or line-level signal into multiple outputs.

Overall EM Rating (1 through 5): 5

Radial Engineering; tel. (800) 939-1001 or (604) 942-1001; e-mail info@cabletek.ca; Web www.radialeng.com