Learn more about the JDX 48

JDX Direct-Drive™ Development

It takes years for a product to achieve ‘industry standard’ recognition. Radial has had the good fortune to gain this level of support for products like the Radial JDI™ and J48™ direct boxes. These are primarily used on bass and acoustic to deliver the pure tone of the instrument with minimal distortion and artifact. In other words, they do not color the sound.


More recently, the Radial JDX 48™ has begun to turn heads by delivering the opposite to the PA system. Instead of sending a pure signal to the PA, the JDX 48 employs a series of filters that color the tone so that it better replicates the sound of an electric guitar going through an amp and guitar cabinet. The reason for this is simple: guitar amps typically employ 12” speakers. They do not employ high frequency drivers or tweeters as these tend to sound harsh and ‘buzzy’. The JDX 48 filters emulate the sound of a Shure SM57™ microphone in front of a Marshall™ 4x12 cabinet. What makes the JDX 48 all the more interesting is that when it is connected in between the amp and cabinet, it also captures the reactive load from the amp and back electro-motive force from the cabinet. This creates a more realistic tone. Is it perfect? No, of course not. There is no substitution for standing in front of Marshall™ stack and moving around to get feedback or just enjoy the sheer power. But with more and more top artists and sound engineers now using the JDX 48 instead of a mic, you can certainly count on it as being good. In fact, very good.

But the JDX 48 has one big problem: It is designed to work with an amplifier. You cannot plug your favorite overdrive into it and do the gig. This is one of the requests that we hear most often. Guitarists do not necessarily want to bring an amp to every gig and in the studio, they often prefer to record quietly instead of blasting out at volume 10. This was the impetus for developing the JDX Direct-Drive.

The Direct Drive basically takes on the challenge where the JDX 48 left off, by simulating the effect of playing through a guitar amp. The advanced filter gives you three options along with a bright switch for options 2 and 3:

  1. Basic JDX sound
  2. Half stack
  3. Open back

Critical to the sound is the way the Direct-Drive emulates playing through a guitar cabinet, while playing through wedge monitors, powered speakers or in-ear monitors. Is it perfect? No, but once again it is very, very convincing and best of all; it will get you there instantly. You just plug in your favorite pedals, select the amp and cabinet tone you like, and presto!

Establishing the feature set was straight ahead. We wanted the Direct-Drive to be super easy to use. So it has a guitar input and a balanced line output to feed the PA system. We then added a thru output that sends the input signal to a guitar amp. This allows the guitarist to use his stage amp while the FOH engineer can capture both the amp and the Direct-Drive signals. He can then mix them together as needed. This output is outfitted with a polarity reverse for phase-aligning the direct sound with a mic, and a ground lift to help eliminate hum and buzz from ground loops.

We then added a tuner out so that we can keep these nasty devices out of the signal path. Finally, we added an AUX out that produces the same signal as the balanced XLR out. This, we felt, could be used to feed a recording system, clean power amp or maybe some special effect. In other words, the Direct-Drive gives you tons of connectivity options. Finally, we arranged the power so that it could employ a standard 9V supply for easy integration into a pedalboard.

The JDX Direct-Drive may well be the first realistic sounding analog amp simulator to ever grace a pedalboard!