The Radial JDX 48 is the next generation version of the popular JDX Reactor amplifier DI. Radial Product Specialist Jay Porter explains: “The JDX has become a staple in professional touring, clubs and houses of worship worldwide. While many engineers were initially skeptical because of previous bad experiences with different ‘red boxes’, the JDX has rapidly gained popularity thanks to its natural, consistent tone. It has also become a go-to piece for use with in-ear monitor systems, delivering a guitar tone that players love.”
“As soon as we released the JDX, folks started asking us if there was any way to power the box using standard 48 V phantom. The included 15 V power supply was fine for most applications, but space and power outlets are always at a premium on stage. Plus carrying multiple power supplies for different areas of the world is painful for our touring clients. We started looking at ways to reduce the current draw of the JDX so it would run on phantom power without sacrificing the exceptional tone, and it wasn’t easy! After several rounds of prototyping, we were finally able to reduce the current requirements of the Class-A circuitry with all of the tone intact.”
“Another request was to increase the power handling of the JDX. While the original was designed for guitar amps with a 100 W output, many folks loved using it with higher-powered amps such as the Ampeg SVT. While this was always possible at lower volumes, extra care needed to be taken to ensure that amplitude peaks did not exceed 100 W.”
The JDX 48’s design begins with the same 100% discrete class-A circuitry and transformer-coupled reactive load found on the original. This captures both the sound from the amp head along with the back electromagnetic impulse from the loudspeaker. This produces a more realistic rendering than the usual resistive pad offered by other manufacturers. This signal is then processed via a carefully designed multi-stage filter to emulate the tone of a 4x12 half-stack cabinet when used with guitar, or a 8x10 cabinet when used with bass. The JDX 48 now also includes a Bass Extension switch for increased bottom end when desired, and a 100 W/300 W switch to change the input capability.
The ability to use 48 V phantom, higher power amplifiers, and add a low frequency extension to the voicing makes the new JDX even more versatile than before. MAP price for the JDX 48 is $199.99.
Radial JDI Stereo passive DI
The new Radial JDI Stereo direct box is also shipping. According to company President Peter Janis: “Stemming back nearly 20 years, the Radial JDI has become the undisputed leader in high-end passive direct box technology and there is no question that the JDI Stereo is sure to follow suit.”
“We have spent countless hours on top, behind and below concert stages, discussing the needs of today’s most demanding technicians. One of the reoccurring themes is the use of two direct boxes to handle a stereo source. And although Radial has been producing stereo direct boxes such as the Duplex for years, the move towards compact setups to lower the cost of air travel has become an important attribute whose time has come. The JDI Stereo is simply the solution to a new problem that is based on economics.”
Features include input and thru-put ¼” connectors plus a -15 dB input pad on each channel. This is supplemented with a ground lift switch that lifts pin-1 on the two XLR outputs to further reduce hum and buzz caused by ground loops. Built tough to handle the abuse of live touring, the JDI Stereo employs a 14-gauge steel I-beam inner frame and a unique book-end outer shell.
The innovative design eliminates stress on the PCB, reducing opportunity for solder joints to go ‘cold’ while the outer shell creates a protective zone around the switches and connectors. The steel enclosure works with the transformer’s mu-metal cans and internal Faraday shield to protect the sensitive inner workings from powerful magnetic fields such as those generated by stage amplifiers. This ensures the signal transfer is quiet and free from hum. The Radial JDI Stereo MAP is $299.
Radial J48 Stereo active DI
Also shipping, the new Radial J48 Stereo is equally suited for stereo instruments or may be used with two different instruments at the same time. A great choice when doubling between bass, acoustic guitar, fiddle or mandolin, the J48 Stereo was the first stereo direct box manufactured by the company.
As Peter Janis explains: “Since the Radial J48’s release in 2001, it has become the world’s most popular active direct box for live touring. Today it can be found on stages as diverse as Paul McCartney, Linkin Park, The Who, Madonna and on live recordings by Tommy Emmanuel (ed: an Australian guitar virtuoso and songwriter for those who don’t know…). What makes the J48 unique is the internal switching power supply. This at once elevates the internal rail voltage for greater headroom and less distortion while providing a method to lift the audio ground without losing phantom power. This produces a wider frequency response, a higher output level over a passive DI and eliminates having to deal with batteries going dead in the middle of a show. For years, we have been asked to come up with a stereo version and we finally got round to it.”
Like all Radial products, the J48 Stereo begins with rugged 14-gauge steel construction and a book-end design that protects sensitive switches and connectors from damage. The internal I-beam ensures the fragile internal PC board will not torque which could lead to premature ‘cold solder joints’ developing, causing joint failure. All connectors are made from glass-filled nylon and are insulated from each other. Extra duty nickel-silver contacts are employed that will not tarnish over time.
Inside, a unique power supply converts the 48 V phantom, increasing the headroom for improved signal handling and lower distortion. This results in a linear frequency response that spans from 10 Hz to 40 kHz while being able to handle high output instruments such as a digital piano or active bass without choking. An additional -15 dB pad may be engaged should the need arise. A built-in high-pass filter gently rolls off low frequencies below 80 Hz to clean up mud and excessive resonance. This is augmented with a side-access 180° polarity reverse that can be handy when using the J48 Stereo with dual element pickups to either phase align the sources or eliminate hot-spots on stage that can cause feedback.
The other benefit of this unique design is the way the J48 Stereo handles hum and buzz caused by ground loops. The traditional solution to eliminating a ground loop is to lift the audio ground by disconnecting pin-1 at the XLR output. When this is done, the 48 V phantom DC power from the console is shut off. Other manufacturers solve the problem by introducing a battery into the equation. Unfortunately batteries are inconsistent, and when they begin to drop power, it can severely affect the available voltage and resulting headroom. Instead, the J48 Stereo employs a DC to DC converter with a high frequency transformer that enables the audio ground to be lifted at the power supply. This does not shut off the phantom power and is invisible to the user.
The J48 Stereo direct box has a MAP of $299.99.
www.radialeng.com
