JDV Mk5™ Using & Applications

The following page describes the basic approach to using the JDV Mk5. For complete details, we invite you to read the manual by clicking the icon at left.

Getting started

The JDV is a dual input direct box that can be used with one or two instruments or be set up to blend two pickups together. There are three outputs including an aux out to feed an on stage amp, a tuner out, and a balanced XLR out for a mixer. As a precaution, always turn off your gear before making connections. This will avoid plug in and turn on transients that can damage more sensitive equipment such as tweeters.

Using the JDV with bass or acoustic guitar

The most common use for a direct box is to capture the clean sound of a bass or acoustic guitar on stage. With the JDV, simply plug the guitar into channel-A and connect the XLR out to the PA system. Set the AB selector to A and then set the level control to 12 o'clock. Bring up your mixer channel to a comfortable level to test. You can add a second instrument by connecting it to channel-B and then toggle between channels using the front panel AB select switch.

Adjusting the Drag™ control

Channel-A Drag™ control load correction is designed for use with magnetic pickups as a means of optimizing the tone for the instrument to sound as if connected directly to a tube amp. It will have very little effect on buffered (active) sources. Start by setting the Drag to 12 o'clock and then adjust to suit. Clockwise will cause the tone to brighten while counter-clockwise will darken the tone. Channel-2 has a 220k-ohm load (medium Drag setting) which tends to work great with most passive basses.

Setting the high-pass filters

Both channels (A and B) can be used with a piezo by setting the DRAG and LOAD switches to the outward position. This sets the impedance to 10 meg-ohms for a broad response without the usual peaks and edginess that often plagues piezos when used with lesser preamps.

Using the JDV with a piezo transducer

Each channel is equipped with a separate high-pass filter that is used to eliminate excessive low end and resonance which can cause resonant feedback with acoustic instruments. The filters range from inaudible 5Hz to 1kHz and rotating the controls clockwise elevates the cut-off frequency. This lets you size the instrument whereby a contrabass would be set lower compared to an acoustic guitar or violin. Rotate until audible, then turn back slightly to set.

Using a microphone with the JDV

A dedicated ¼" TRS input is available to connect an instrument-mounted microphone to the JDV. As these are usually condenser, the JDV will also produce 48V phantom power. As a safety measure to prevent harming pickups, the 48V phantom must be activated each time the JDV is turned on (provisions are available to bypass this). To connect, use an XLR to ¼" TRS cable with tip hot (+), ring cold (-) and sleeve to ground.

Combining two sources

A side access blend function enables both A and B channels to be used at once. This enables two instruments to be used at once or to enable two sources such as a mic and a piezo to be active on a single instrument. Channel-A can be used for piezo, magnetic, active or mic while channel-B is designed for piezo, magnetic or active sources. Once both are on, simply adjust the levels to suit.

Using the built-in Radial Phazer

The built-in Radial Phazer on channel-B adds a significant degree of realism by allowing you to phase-align the fundamentals for the instrument to compensate for distances from the sound hole or bridge. Set the Phazer control fully counter-clockwise and turn it on. Slowly rotate as the instrument is being played to hear the effect. Try reversing the polarity to increase the range. Keep in mind that moving the microphone will cause the phase relationship to shift!

Recording direct to a line level input

Most of the time, the JDV will be used at mic level from the XLR output to a mic input on a mixing console. When recording, it may be preferable to record direct to the line level input on a mixer. A special +20dB line level booster may be activated to increase the output for this application. This also enables the JDV to be used with an active speaker instead of a bass amp.

Adding the JR-2 remote control

You can add a remote control footswitch that lets you toggle input channels or mute the JDV for quiet on stage tuning. Simply connect using a TRS cable and the JDV will power the LEDs on the JR-2 to provide visual status on the floor in front of you.

Rack-mounting the JDV

The JDV comes standard with an easy carry handle that lets you quickly move the JDV around the studio using one hand. The handle can be removed and an optional rackmount kit may be attached to allow one or two JDVs to fit inside a single 19" rack space.