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They May Not Be Sexy, But They Sure Are Useful


each ($199 street)



By Craig Anderton


Sometimes it's not the come-hither new toys, but the useful little boxes that end up getting reached for gig after gig, session after session. Radial Engineering is a Canadian company that specializes in those little boxes, making sturdy devices built to rock and roll specs. They tend to cost a bit more than products designed to do similar functions, but are engineered - if not over-engineered! - for sound quality and durability. In fact, when I reviewed their JDV direct box several years back, I was so impressed with what it did for the sound of my electric guitar when recording direct that I bought it. I still have it, and it still works.

This review covers a pair of boxes, the J48 direct box and X-Amp re-amp box, because they work well together. Let's check 'em out.



J48 main shot.jpg

The J48 uses Radial's standard construction techniques: a heavy, all-metal, 14-gauge welded steel case with a panel that folds over the main chassis, providing a lip that gives protection to the switches and knobs mounted on the ends. A non-slip pad covers the bottom, so the box won't slide around if on the floor, or scratch your desk if it's on a desktop.

The J48's main claim to fame is no batteries and lots of headroom, because it gets its voltage from phantom power. So, if you don't have an XLR input with phantom power into which you can plug the J48's output, might as well move on to the X-Amp part of the review. (Well actually, there is a way to mod the J48 to run off batteries; you need to contact Radial for the details. But that sort of negates one of the best features of this particular box.) The advantage of this approach is that by converting the +48V from phantom power to provide a 9V power supply rail, there's plenty of headroom. If you have a high-output acoustic instrument with a piezo preamp, active guitar, or guitar with super-hot pickups, you're probably not going to get distortion or clipping (and if you do, there's an input pad switch). Furthermore, a transformer isolates the 48V power to minimize the chance of getting ground loops.



J48 end 2.jpg

The picture shows the "input end" of the J48 (to see additional pictures and the complete set of specs, click here). Note another Radial feature: The function of the jacks and switches are printed on the top, so you can see what's plugged into what without having to lift the box up to see the labels on the end.

The Input is designed to handle a mono out, like from a guitar, while the Thru passes that signal along to some other device - a tuner, perhaps, or an amp that provides an "amp" sound while you take the main sound direct to a mixer. However, note the Merge button; when in, it combines the Input and Thru jacks to the mono out. This allows plugging in devices with stereo outs, although the ultimate result will be mono.

The remaining controls are a -15dB pad switch, and also, an LED to indicate that 48V is present. This "check" function works in conjunction with the output's Low Cut switch - press the switch, and the LED flashes for an instant.



J48 end 1.jpg

The output is a standard XLR out (600 ohms, pin 2 hot). A polarity reverse option switches pins 2 and 3 to reverse phase, while a Low-Cut filter reduces response by -6dB at 80Hz. It's not exactly brickwall, but can help tame subsonics and mud a bit. Finally, the ground lift switch breaks the input/output ground connection just in case you encounter a ground loop.



The J48 works exactly as advertised. The sound quality is extremely clean, and the box would definitely survive the "drop test." I was not able to overload it with any of the passive guitars I tried, although using some line level synths with "hot" outputs could cause clipping (the pad switch solved that, but then again, I usually plug line-level devices into an audio interface - there's no need for a direct box). I didn't experience any ground loops so I couldn't test if the ground lift switch makes a difference, but given what it does from a technical standpoint, I expect that it would.

Bottom line: This is a direct box for those who want something pretty much indestructible, with excellent sound quality and headroom, and are willing to pay a bit more for the privilege. Since I bought the JDV, I've never felt the need to replace it; my take is that if a J48 would find an equally permanent home wherever it lived.



Xamp main.jpg

The X-Amp is a slightly more complex product, designed for a more complex task: Re-amping. If you need a refresher, the idea behind re-amping is you record a dry guitar sound into your recorder, then send it out to a guitar amp to get your tone "after the fact." Or you might use re-amping on two separate passes, one to add a track using one guitar amp, and another with a different guitar amp, to get a big stereo spread. In case you're wondering why I reviewed the J48 and X-Amp as a pair, it's because you need to record a dry signal before you can re-amp it...which of course is what the J48 does.

These days, a lot of re-amping is done "in the box" with plug-ins. For example, if you're using software like NI's Guitar Rig, IK Multimedia AmpliTube, Waves GTR, etc., and routing your guitar through the computer, you're actually recording the dry guitar sound and modifying it on playback (or during monitoring) with the plug-in. Thus, you can change the sound at any time, up until the final mixdown.

Traditional re-amping is hardware-based, and that's what X-Amp does. Its main task is to provide impedance and level conversion from a pro mixer's high levels to the low levels required by guitar amps, which allows for efficient signal transfer without distortion. The electronics is active, using Class A amplification, which draws more current than other classes of amplification but provides very low distortion and excellent clarity.



The input section is straightforward. (To see more pictures and the complete set of specs, click here.) There's an XLR line level input, designed to the take the output from an amp, along with a ground lift switch and jack for the wall wart AC adapter. Pretty simple.

The output is more involved. First of all, there are two outputs: One direct, and one transformer-isolated. The isolated output also has a polarity reversal switch, and an internal ground lift switch which defaults to lifted, as it's assumed you'll always use the primary out with a properly-ground amp, while the second out is just for adding a second amp. If you need to ground the second amp, there's a little hole in the side of the case where you can poke the switch using something like a straightened paper clip, and defeat the output 2 ground lift.

You'll also find a level trim that affects both outputs. A clip LED indicates whether the signal feeding the X-Amp is too hot.

Xamp end 2.jpg

Xamp end 1.jpg



Like the J48, using the X-Amp is pretty straightforward. The only real issue is getting your grounding right. As with the J48, I didn't encounter any ground loop problems (I guess my studio's pretty clean, which is kinda nice to know). But I could see that if you were in a studio situation, running long lines, and connecting amps and mixers in different parts of the studio, grounding could indeed be an issue so it's good that Radial has taken this into account. However, note that the X-Amp is designed for "pro" applications: its input expects to see an XLR out with a +4dB signal level. If you're using inexpensive unbalanced gear, you'll need an adapter to take advantage of what the X-Amp can do.



I've always been impressed by two aspects of Radial products: The construction and the clean sound quality. The J48 and X-Amp are no exception. They may be overbuilt for your particular needs, but if you need a really pro direct and/or re-amp box, these two products definitely deliver the goods.


CraigGuitarVertical.jpgCraig Anderton is Editor Emeritus of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.

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