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True to the Music
Radial JD6
Six channel rack mount D.I.
User Guide
Radial Engineering Ltd.
1638 Kebet Way, Port Coquitlam BC V3C 5W9
tel: 604-942-1001 • fax: 604-942-1010
email: info@radialeng.com web: www.radialeng.com
www.radialeng.com
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Radial JD6 Owner’s Manual
TABLE OF CONTENTS PAGE NUMBER
1. Introduction ....................................................................................................................................1
2. The JD6 Design Concept ..............................................................................................................2
3. Development of the JD6 ................................................................................................................2
4. Rear Panel Connections ................................................................................................................5
5. Using the JD6 ................................................................................................................................6
6. Grounding Options for the System Engineer .................................................................................7
7. Typical Stage Set-up Using the Radial JD6 ...................................................................................8
8. Typical Studio Set-Up Using the Radial JD6 .................................................................................8
9. Optional Output Panels .................................................................................................................9
10. The Advantage of Going Passive! .................................................................................................9
11. Radial JD6 - Questions & Answers ..............................................................................................10
Warranty Information ......................................................................................................Back Cover
1. INTRODUCTION
Congratulations on your purchase of the Radial JD6 multi-channel direct box. The JD6 is a world-class 19" rackmountable DI system that has been optimized for use with keyboards, audio-visual equipment, computer sound cards,
samplers, electronic drums and instruments of all types.
As there are many innovative features in the JD6, we recommend that you take a few minutes to read through this
manual in order to familiarize yourself with the design and features that are built in. Most importantly, the Radial
JD6 features internal grounding options that will be of particular interest to engineers when integrating the JD6 with
keyboard racks and audio-visual systems.
Should you have a question or application in mind that is not covered in this manual, we invite you to log onto the
Radial web site at www.radialeng.com to check the Questions and Answers section for the latest updates. Of course
you can also send us an email at info@radialeng.com should you have a particular need.
Have fun!
Radial Engineering
1638 Kebet Way, Port Coquitlam BC V3C 5W9
tel: 604-942-1001 • fax: 604-942-1010
email: info@radialeng.com web: www.radialeng.com
Specifi cations and appearance subject to change without notice.
Radial Engineering JD6 Owner’s Manual
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True to the Music
2. THE JD6 DESIGN CONCEPT
Over the past several years, there has been a shift in the way keyboards, digital samplers and electronic drums have
been used in live sound. Most notable has been the integration of the portable PC (personal computer) and sound card
as part of the musical array. Add to this the insurgence of the disk jockey and his assortment of scratch samplers and
one can begin to foresee the need for a new interface to ‘tame the beast’.
Live sound is but a portion of this emerging market. The introduction of affordable 24bit / 96kHz technology has
allowed the musician, artist and engineer to fashion a ‘home offi ce’ and create a completely viable project studio in
the comfort of a spare room. The same live touring equipment must be able to transition from the road to the studio
right along side the computer.
Ultimately it must be easy to use, be able to adapt to a variety of set-ups, be compact for maximum rack density and
sound absolutely amazing. And uh… did I mention that it must solve all those nasty ground loop problems that cause
keyboard technicians to have nightmares?
3. DEVELOPMENT OF THE JD6
The Radial JD6 is a 6-channel version of the highly successful Radial JDI direct box and supercedes
the Radial JD4 as the new standard 19" rack mounted direct box. Upon inspection you
will notice that channels 1 and 2 differ from channels 3 through 6. A ‘Swiss
Army knife’ approach is introduced to allow the 1st two channels on
the JD6 to be problem solvers for stage and studio. Added
features include a high frequency fi lter to reduce noise,
a merge function to mix left & right keyboard
outputs to mono and choice of ¼” inputs or RCA ’ s
for improved interfacing with audio-visual equipment
and computers. The other 4 channels address basic DI
requirements as normally required for keyboards, electronic
drums and other electronic devices.
As with all Radial direct boxes, the audio signal path is of utmost importance. The Radial JD6 is a passive direct box
and employs the Radial's fi nest Eclipse™ audio transformers for absolute performance. You can hit the JD6 with tons
of level and you will never saturate the core! At less than 0.006% distortion at 20Hz, the JD6 has no equal. However
harmonic distortion is only part of the story: the Radial JD6 exhibits less than 4º phase deviation at 20Hz making it the
ultimate choice for keyboards where extreme dynamics and wide frequency range is required. There is nothing more
demanding on electronics than a digitally sampled grand piano and the JD6 handles these dynamics without altering
the tone, introducing phase shift or intermodulation distortion.
Key features on the JD6 include switching jacks for channels 1 and 2 whereby the front jacks take priority over the
rear panel jacks. This is of particular importance in studio set-ups where the JD6 can act as a patch bay to quickly
reconfi gure the signal path.
To add greater effi ciency for touring, a series of extension panels with individual and multipin connectors are also
offered. Furthermore, each channel of the JD6 has been provided with internal grounding switches to allow the system
engineer to select between fl oating and chassis grounding for maximum fl exibility.
Of course, as with all Radial products, the JD6 is designed to handle the most abusive environments. W elded 14 gauge
steel construction, baked enamel fi nish, high-cycle rate switches and glass-fi lled high-impact polymer connectors with
nickel silver contacts combine for maximum durability. The Radial JD6 is supported with a 3-year limited warranty.
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FRONT PANEL FEATURE AND FUNCTION SET
1. Pad, -15dB for extra hot signals
2. Filter, 8kHz high frequency roll-off
3. Polarity reverse, 180º ‘phase’ fl ip at the XLR
4. Ground lift switch lifts pin-1 at the XLR
5. Input connector from the instrument
6. Thru-put connector goes to the amplifi er
True to the Music
7. Merge mixes the input and thru to mono at XLR
8. Input selector switch selects between ¼” and RCA
9. RCA input connectors (pre-merged)
10. Wax pencil or dry-erase label ID on each channel
1. –15dB pad: All channels of the Radial JD6 feature a -15dB pad to reduce the level coming from high output sources
such as CD players, tape machines and headphone outputs. It is unlikely that you will ever need to use a pad for basses
or guitars.
NOTE: When using a headphone output as a ‘source’, activate the –15dB pad and make sure the headphone level is
fi rst set to zero. Then, slowly increase the volume until it matches the output from an instrument such as a keyboard.
Headphone outputs are much hotter than instrument levels and if not careful, can saturate the transformer and
cause distortion.
2. 8kHz fi lter: Channels 1 and 2 feature a gentle low-pass fi lter that rolls off highs at 8kHz. This is designed to remove
hiss and noise from older high output equipment and the upper frequency hash that is common in many of today’s
electronic devices. The fi lter can often help remove induced noise from CRT monitors and other electro-magnetic stray
fi elds. To engage the fi lter, the pad must also be depressed.
3. 180º polarity reverse: The 180º polarity reverse is used to reverse the polarity (sometimes called absolute phase
reverse) at the XLR by fl ipping pin-2 and pin-3. This is used when interfacing with older equipment that was made before
the AES pin-2 standard was adopted. It can also be used in a creative way when combining direct and mic’d sources.
4. Ground lift: The ground lift switch is used to disconnect pin-1 at the XLR thus providing 100% isolation. The JD6
is passive and employs isolation transformers throughout, so problems such as 60-cycle hum, ground loops and other
noises associated with electronic equipment are generally eliminated. Lifting the XLR ground connection presumes
you intend to ground the JD6 at the input.
NOTE: Inside the JD6 are individual chassis ground lift switches. These are factory set to fl oat thus providing
isolation between adjacent channels and provide 100% fl oating circuits as if using 6 separate direct boxes. This is
detailed further in the manual.
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