1.

The Radial JDV begins with an input selector for choice between two instruments. Often, when recording, the simple act of picking up another instrument will cause the musician to play a passage differently and often, this change can lead to magical results. In concert, being able to pick-up a spare or alternately tuned instrument without having to reconnect is a joy.

On the left, three LED indicators provide power-on, signal present and overload status. Two on-board filters are provided. A low-cut filter (high-pass filter) is used to reduce rumble and run-away resonant feedback from acoustic instruments. For bass, this will tighten up the bottom end without losing the fundamental. A high frequency roll-off (low-pass filter) gently rolls off noise from older equipment and helps tame overly brittle instruments.

The JDV Mk3 includes a special feature we developed called Drag Control™. This function was originally developed on the Radial JD7 Injector as a means to re-introduce the loading that is lost when the guitar pick-up no longer is coupled directly to the amplifier. Laboratory engineers have perpetuated a ‘myth’ that ‘loading the pick-up’ is a bad thing when in fact, correcting the load is critical to achieving musical results. Without proper impedance matching, the sound can become brittle and harsh. This of course is most noticeable when recording.

The JDV offers a choice of a 3.9 Meg-ohm input impedance (the highest in the industry) to properly match piezo pickups and variable loading we call Drag Control™ that combines resistance and impedance with a single dial for effective load correction.

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The output panel is the engineer’s zone. The XLR output provides a clean, unaffected signal to the console for future processing or doubling with the mic’ed performance. Because of the JDV’s huge internal rail voltage and exceptional dynamic handling, an output pad is provided so that it will not overload the console or pre-amp. A polarity reverse switches the XLR output from AES standard pin-2 hot to pin-3 to adapt to vintage equipment while providing another creative tool to broaden the audio landscape.

The JDV Audio Path

The most important feature of the Radial JDV is the sound quality. At Radial, we pride ourselves in the fact that our direct boxes do not change the original sound or impose a particular EQ curve to an instrument. We do not believe it is our place to alter the sound of pre-CBS Fender or a PAF equipped Gibson. Our task is to provide the original sound of the instrument without adding color, distortion or hype. We call our sound the Un-Sound™.

To achieve this level of audio purity, every aspect of the Radial JDV’s circuit must be optimized for minimal distortion. And unlike other manufacturers, we do no just examine harmonic distortion, but zealously try to eliminate zero-cross distortion, phase distortion, inter-modulation distortion, linear response distortion, square wave distortion and headroom. By treating each of these carefully, the result is predictable: you get great sound.

The Radial JDV employs a unique Class-A feed-forward circuit design and a newly developed high-voltage, low-noise power supply. Class-A circuits although less efficient, do not suffer from zero-cross distortion. This is why Class-A circuits are ‘the choice’ for audiophiles. The JDV’s unique feed-forward design means that we have eliminated the traditional stabilizing feedback loop that is in the ‘easy circuit designer’s handbook’. This unique ‘high-wire without a net’ circuit design is amazingly adept at handling square ‘pulse’ waves without ringing or overshoot. Put the JDV up on a scope and one will see a sharp, 90 degree rendering that is unequaled in the business.

The exceptional internal 30-Volt rail voltage is of particular importance at bass frequencies. In PA systems, bass drivers are commonly driven with as much as ten times more power than the high-frequency drivers. This is because bass, with its longer wavelengths, requires significantly more power to generate. This is the same at the circuit level and is critical to achieving a tight, natural sound. Look inside the JDV and you will see huge current storage capacitors that are the size found in small power amplifiers. By providing ample impulse energy storage, dynamics are maximized thus fulfilling the capacity of today’s most advanced recording devices. The benefit of having upwards to 10 times more headroom than a traditional DI means that the JDV never chokes even with the most powerful active bass or extreme digital sample.

Using the JDV