Radial JDV MK5 Class-A Direct Box
The Radial JDV MK5 Class-A Direct Box brings all of the fantastic sound and features of the classic JDV mk3 into Radial's new Stand Alone (SA) chassis format and expands upon them to make a top-tier DI that not only performs admirably in the studio, but can also be a player's first choice DI for stage, as well.
The Radial JDV Mk5 is a high performance active direct box and preamp with two inputs that enables the user to seamlessly transition from one instrument to another while being able to optimize the signal chain no matter what the source.
The design begins with 100% discrete electronics and a unique class-A circuit with zero phase-cancelling negative feedback front-end. This is augmented with Drag™ control load correction that lets you optimize the impedance that is being applied to the pickup along with extra rail voltage for an abundance of headroom. The result is virtually zero harmonic, phase and cross-point distortion resulting in the most natural rendering without coloration or artifact of any type.
Central to the design is the JDV's ability to handle any type of instrument. Input-1 is equally well suited for magnetic pickups or active instruments and is equipped with a balanced mic input with 48V phantom to accept instrument-mounted condenser mics. Input-2 adds another dimension with a selectable 10 meg-ohm input to properly load piezo transducers. Both inputs may be active at one time and mixed together using the front panel controls. These can then be phase-aligned using the built-in Radial Phazer for what can only be deemed the most natural sounding reproduction of an acoustic instrument ever.
Extra features include fully variable high-pass filters on each channel to eliminate excessive low frequency resonance, easy-read LED level meters, Jensen Transformer isolated outputs to eliminate hum and buzz caused by ground loops and a +4dB line level output for direct recording. Switching between channels may be done using a front panel switch or via the optional JR-2 remote control.
The Radial JDV Mk5... the only DI you will never hear!
JDV Mk5 Development
The origins of the JDV can be traced back to the 1980's where Vancouver was a hot-spot for some of the most commercially successful recordings of all time including works by artists Bryan Adams, AC/DC, Metallica, Elton John, Aerosmith, Loverboy and Bon Jovi. Home to Bruce Fairbairn and Bob Rock, Little Mountain Studios was the epicenter.
Behind the scenes, was studio designer and technical whiz John Vrtacic. John was the guy that designed monitors, modified and rebuilt the consoles and created many of the unique tools that set Little Mountain Studios apart. Artists would often talk about the amazing bass sound that John's custom-made direct box produced. John had discovered a way to buffer the signal without the use of negative feedback and when scoped, his DI produced an incredibly accurate sonic picture that was simply unattainable by any other.
Soon after Radial launched the Radial JDI passive direct box, we asked John's assistant Ron 'Obvious' Vermulen to compare various direct boxes using his Audio Precision tester to prove that the JDI was best. During these tests, unbeknown to us, Ron also tested John's custom made direct box. This is how we discovered that John's box was so much better than the other active DIs on the market. We approached John to see if he would sell us the design. He did and the first generation JDV – V for Vrtacic – was born.
Updating the feature set
Over the years, the JDV has gone through several changes. During each evolution, improvements have been made to enhance the performance while remaining true to John's original design.
Connectivity and level controls
Although the previous JDV had two inputs, you had to manually select between them using a side panel switch. We felt that it would be advantageous if the artist could select the instrument by also using a remote footswitch. Being able to adjust the level between the two instruments also enables the artist to switch between an active bass and a passive one without having to readjust the levels on the bass amp or mixer channel.
Today, source instruments can range from simple magnetic pickups, to piezos, active sources or even microphones. To our mind, the JDV had to do it all. Magnetic pickups tend to sound warm and natural when they see a 200k-ohm load. Yet piezos need to see a 10 meg-ohm load in order for them to sound full and natural. The JDV has it all including Radial's unique Drag™ control load correction that lets you adjust the load to suit a particular pickup and playing style.
Adding a microphone
There is no question; a well positioned microphone in a proper acoustic environment will produce the most natural sound of all. The problem however is that when used live, mics can pose a number of challenges including positioning, feedback and of course the less than ideal sound that is produced when excessive EQ'ing is applied. Combining the sound of a piezo with a microphone helps tremendously as the pickup can produce a greater output. The real magic however comes when you phase-align the two sources. To this end, we added a mic input, 48V phantom, and a Radial Phazer.
Filters and control
One of the most amazing tools you can use on stage (and in the studio!) is a high-pass filter. This simple control eliminates low frequency resonance that can cause an instrument to get muddy and cause weird feedback on stage. With two HPFs, the new JDV allows you to dial-in the size of the instrument so that your upright, acoustic guitar, viola, mandolin or fiddle will properly sit in the mix without getting lost.
The optional Radial JR2 ABI Select & Mute Control Foot Switch actually does more than simply select input channels. It can also be used to mute the output going to the PA or stage amp while leaving the dedicated tuner output on at all times. This of course enables quiet on-stage tuning while eliminating the confusion and panic that can occur when the artist decides to change instruments mid-way through a song due to a broken string. Muting the instrument means that the monitor and FOH engineers do not need to turn down the acoustic channel – the artist can merely mute it as needed.
With more and more recording and tracking being done in the comfort of private studios, session players are often called to these remote locations where they will record direct for further Reamping after the track has been laid down. A special signal level booster may be activated that increases the output from a typical DI out by 20dB to enable direct line level recording. This assures your bass track will be recorded with maximum fidelity no matter what the equipment setup.
More than ever, stage managers are insisting on having backups on stage to content with any and all eventualities. When 20,000 fans are in the audience, there is no time for system breakdown. And even though Radial is well known for having the least service problems in the industry, having a backup is the best insurance you can ever have! The new JDV can be rack mounted individually or two may be mounted side by side for the most demanding tours by using the Radial SA19 Rack Adapter.
Global power supply
Global touring a reality, power supply issues have now become a significant concern. The new JDV employs an external switching supply with a locking XLR that is able to handle any input voltage from 100V to 240V. One merely changes the IEC cable to suit.
Radial JDV MK5 Class-A Direct Box Features
- 100% discrete class-A active direct box
- Feed forward design – no negative feedback
- Drag control load correction for natural tone
- Huge 30-Volt rails for exceptional headroom
Radial JDV MK5 Class-A Direct Box Specifications
- Instrument input circuit: without negative feedback
- Instrument clip level: +18dBu
- Microphone input circuit: Low noise integrated circuit
- Microphone clip level: -11dBu
- Frequency response: 20Hz - 20KHz
- Dynamic range: 107db
- Equivalent input noise: -90dbu
- Common mode rejection: -80dB
- THD+N: 0.004%
- Clip level - output: +17dBu
- Gain - instrument input: +25db
- Gain - line level boost : +20dB
- Gain - microphone input: +25db
- Input Impedance: Drag on: Variable from 22K Ω ~ 500K Ω
- Drag off: 10M Ω
- Output impedance at XLR: 400 Ω
- Instrument inputs: 1/4" selectable A or B with front panel switch or remote
- Blend: Mixes both A and B channels together
- Drag Control: Load correction for 1/4" instrument inputs
- High-pass filter: Variable from 5Hz ~ 500Hz @ -3dB
- Remote footswitch: Optional JR-2 for mute and channel select
- Mic input: 1/4" TRS on channel-A
- Phantom power: 48V on mic input, side access switch
- Phase adjustment: Phazer on channel-B, variable from 0° ~ 360°
- Throughput: Buffered THRU with direct or isolated setting
- XLR output: Balanced mic level with 20dB line booster switch
- Isolation: Transformer isolation option for XLR output
- 180° Polarity: Reverses pin-2 and pin-3 on the XLR output
- Ground lift: Disconnects pin-1 at XLR output
- XLR configuration: AES standard pin-1 (ground), pin-2 (+), pin-3 (-)
- Power: External 100V - 240V AC with 48V phantom
- Construction: 14-gauge steel chassis and outer shell
- Finish: Durable powder coat
- Size: Size: 5" x 6.25" x 2" (127 x 159 x 51mm)
- Weight: 2.80lbs (1.28 kg)
- Conditions: For use in dry locations only between 5°C and 40°C
- Warranty: Radial 3-year, transferable
Radial JDV MK5 Class-A Direct Box Includes
- JDV Rev 5 Class-A Direct Box
- Global Power Supply
- Manual & Literature
- Radial 3-year, transferable warranty
- Optional Accessories:
Radial JDV Rev 5 Class-A Direct Box Downloads
What We Think
"The Radial JDV has always been a very impressive sounding DI box. I've known it to provide an incredibly clean and musical sound over even the fine sounding J48 design (which I own along with a JDI). The mk3 provided tons of connectivity which made it a handy Swiss Army Knife in the studio, but the footprint and ergonomics (lack thereof?) made it a bit weird to take on the road. Plus, it's Wall-Wart PSU seemed a little clunky if not as pro as the unit actually is. As a result, the mk5 was developed to take advantage of the footprint developed for the Firefly. The result is a new design which adds lots of tweakability together with lots of stage ready options (A/B remote switch and rackmount options). The same great DI sound that was made famous on tons of classic albums made at Little Mountain Studios in Vancouver (Aerosmith's Pump, is just but one of them) now has a new feature set which makes it comfortably at home on stage as well."
Alan Moon - Front End Audio
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