The Radial Engineering JDV-Pre Instrument Preamp & DI is a preamplifier that is specifically designed to capture the natural tone and distinct character of the instrument. It is completely focused on the various types of pickups used, while transferring the signal without introducing distortion or artefact of any type.
The design begins with a 100% discreet class-A amplifier for optimal signal transfer. But unlike all other amplifier designs, the JDV-Pre Instrument Preamp & DI’s front end is completely void of the negative feedback loops normally used to stabilize the circuit. This design eliminates the use of phase-cancellation, which inevitably degrades the signal. This is augmented with Drag Control load correction that allows the engineer to optimize the load on the instrument pickup for the most natural rendering.
When the impedance is set for piezo pickups, the JDV-Pre Instrument Preamp & DI’s remains quiet. Accustate gain control not only allows complete freedom over the signal path, but retains the signal-to-noise ratio at all levels. Acoustic instruments are further advantaged with a fully variable high-pass filter that gently rolls off the low end to eliminate troublesome body resonance, while allowing each instrument to sit more comfortably in the mix. To address instrument microphones, the JDV-Pre features a transformer-coupled balanced microphone input with available 48V phantom power for condenser microphones. The connection is made via standard 500 series rack XLR input.
It reverses the polarity on the JDV output. It is suited for eliminating feedback on stage or can be used to phase align 2 signals better for improved stereo imaging.
The XLR input enables the JDV-Pre to be used with an instrument microphone. The transformer is coupled for optimal signal flow.
The 3 separate LEDs with On for Power, Signal Present, and Peak Overload provide visual feedback of the JDV-Pre signal and operating status.
It is designated as a balanced low-impedance direct box output, designed to feed a snake system and mixing console in a live touring environment. (Only with Workhorse)
Sets the accustate level control to simultaneously adjust the gain and input sensitivity to ensure lowest possible noise at all settings.
The HPF (High-Pass Filter) reduces low-frequency resonance and helps clean up the sound of acoustic instruments while eliminating runaway feedback. It is suitable for layering tracks when recording.
Engaging the Drag On control shifts the JDV input impedance from 3.9 MΩ for piezo pickups to a variable load that can be set from 22 to 500 kΩ for magnetic pickups.
The Drag Control lets you replicate the load of a magnetic pickup as if connected to a tube amplifier. This results in producing a smooth and natural tone. It is great for bass and guitar.
The switching jack input is used to connect an instrument to the JDV-Pre. It has front panel priority over the XLR mic input on the rear panel of 500 series rack.
Buffered output is used to feed a guitar or bass amplifier when recording. The transformer that is isolated eliminates the buzz and hum caused by ground loops.
Unique 100% Discrete
Discrete class-A front input circuit is void of typical negative feedback loops for optimal signal transfer without phase canceling of any sort.
Mil-Spec Circuit Board
Features double sided PCB and full ground plane to assure the lowest noise and durability for years of trouble-free performance.
Gold Plated 15-Pin Card Edge
Double sided to ensure positive connection to the receptacle for improved mating.
Transformer Coupled Input
The JDV-Pre has mu-metal shielding for extra isolation from ground loops and electro-magnetic interference while delivering the added warmth of an old school transformer circuit.
A 12-position Grayhill switch features gold contacts and a steel shaft for years of trouble-free performance.
Doubled up solder points ensure durability. Steel casing with steel shaft and retention nut will not bend when under stress.
Double Layer Front Panel
Steel construction adds rigidity to reduce stress on the PC board.
The Microphone Channel: Bass with magnetic pickups and stage amplifier
Tracking Instruments: Violin with passive piezo pickup attached to bridge
The Basic Setup: DPA 4099G clip-on microphone with acoustic guitar
In the Box
Radial Engineering JDV-Pre Instrument Preamp & DI
Limited 3-Year Warranty on Parts & Labor
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100% discrete, class-A input
20 Hz to 20 kHz, +0 / -4 dB
Equivalent Input Noise
Inter-Modulation: <1% at 4 dB
THD + Noise
<0.05% at 4 dB
1/4" Input: 3.9 MΩ (drag off)
1/4" Input With Drag: 22 to 500 kΩ
XLR Input: 7 kΩ
XLR Input with Drag: 450 to 2.7 kΩ