Radial Engineering JD6, R800 6000 Owner's Manual

True to the Music

Radial JD6
Six channel rack mount D.I.

Part # R800 6000

Owner’s Manual

Radial Engineering
1638 Kebet Way, Port Coquitlam BC V3C 5W9
tel: [phone] • fax: [phone]
email: [e-mail] web: www.radialeng.com

www.radialeng.com

Radial Engineering is a division of JP CableTek Electronics Ltd.

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 [e-mail] should you have a particular need.

Have fun!

Radial Engineering
1638 Kebet Way, Port Coquitlam BC V3C 5W9
tel: [phone] • fax: [phone]
email: [e-mail] web: www.radialeng.com

Radial Engineering is a division of JP CableTek Electronics Ltd.
Specifications and appearance subject to change without notice.

Radial JD6 Owner’s Manual • V1.0 • 07-30-03 (Ref # R800 9647 00)

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 office’ 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 filter 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 world’s finest Jensen™ 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
reconfigure the signal path.

To add greater efficiency 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 floating and chassis grounding for maximum flexibility.

Of course, as with all Radial products, the JD6 is designed to handle the most abusive environments. Welded 14
gauge steel construction, baked enamel finish, high-cycle rate switches and glass-filled 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’ flip at the XLR

4. Ground lift switch lifts pin-1 at the XLR

5. Input connector from the instrument

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.

6. Thru-put connector goes to the amplifier

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

NOTE: When using a headphone output as a ‘source’, activate the –15dB pad and make sure the headphone
level is first 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 filter

Channels 1 and 2 feature a gentle low-pass filter 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 filter can often help remove induced noise from CRT monitors and other electro-magnetic stray fields.
To engage the filter, 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
flipping 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 float thus providing
isolation between adjacent channels and provide 100% floating circuits as if using 6 separate direct boxes. This
is detailed further in the manual.

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5. Input connector

For maximum flexibility, the Radial JD6 features both front and rear ¼” input and thru-put connectors on channels
1 and 2. Normally, the connection would be made on the rear to allow samplers, sound modules and rack-mounted
mixer input & output connections to be made within the rack enclosure.

T o facilitate connections to outside equipment such as keyboards or computers, the two first channels feature ‘priority
switching jacks’ on the front panel. This means that when the channels are normally connected using the rear panel
jacks, the front panel jacks will divert the input giving these priority, thus temporarily disconnecting the rear jacks
until such time as the front panel input jacks are removed. This is of particular advantage in a studio where the JD6
may be ‘wired’ to a patch bay for the keyboards. To patch in a bass, one would simply plug into the channel-1 front
panel ¼” jack and start recording.

NOTE: Since most rack equipment is connected via rear panel connections, the JD6 adopts the same standard.
This allows clear unobstructed view of the front-panel controls. To facilitate more complex system routing and
provide greater flexibility, optional extension panels are also available. This is detailed further in this manual.

6. Thru-put connector

As with all direct boxes, the JD6 is outfitted with a thru connector on each channel. This is used to pass the direct
signal directly thru to the instrument amplifier or sub mixer. On channels 1 & 2 these are also duplicated on the
front and the rear of the unit and feature switching jacks with front panel priority. Normally, the thru will be
connected on the rear panel. By inserting a jack into the front panel THRU connector, the signal will be diverted to
the front jack and disconnect the rear connection.

7. Merge function

Channels 1 & 2 also feature a function called Merge. When this switch is depressed, it turns the Input and Thru-put
connections into a ‘left and right’ mix to mono at the XLR output. This passive (resistor) mix or summing function
is a real helper when there are insufficient snake or mixer channels to handle over-abundant channel feeds in some
keyboard set-ups. For instance, by depressing the merge function, a pre-programmed stereo sound module would
not have to be reprogrammed. One would simply connect left and right outputs as usual and these would be summed
mono at the XLR. The dual RCA’s on each channel are automatically set to perform the same function. Depressing
the merge switch affects both the front and rear jacks.

8. Input selector switch

A selector input switch on channels 1 & 2 toggles between the ¼” input and the RCA jacks. This handy feature
allows channels 1 & 2 to work ‘double time’ whereby one could instantly switch between a rack module and a sound
card during a performance by simply depressing this switch.

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9. RCA inputs

A set of RCA input jacks are located on the front panel on channels 1 & 2 to interface with CD players, computer
audio cards and other audio-visual equipment that is often combined in today’s stage environments. By depressing
the RCA selector switch, both rear and front ¼” inputs are diverted to the RCA inputs. Two RCA connectors are
pre-merged (mixed to mono at the XLR) as most RCA source equipment comes from the consumer stereo world. To
retain stereo operation, one must use two channels on the JD6. To facilitate this, the RCA connectors of channels 1
& 2 are located side by side, thus reducing cable mess on the front panel.

10. Easy ID label zones

Both front and rear panels feature ‘labeling’ zones for wet-erase or wax pencil channel identification. These handy
ID spaces are designed to facilitate complex set-ups by providing easy to see channel information directly on the JD6
and will be of particular importance when using several JD6s in a rack for concert touring.

NOTE: As these white label zones are screened directly on the metal, only use an erasable pencil such as a wax­pencil or dry or wet erase pencil to mark the JD6. We strongly suggest you test your pen or pencil to make sure
the ink does not react with the screening. Before permanently marking the front panel, check that your marker
can be erased by testing a small sample on the rear panel. As there are many different manufacturers of markers,
we cannot assure that these will work as intended.

4. REAR PANEL CONNECTIONS

Upon first inspection, the rear panel connections appear to be identical for all channels. Although true, it should be
noted that channels 1 and 2 employ switching jacks with front panel priority. This means that these channels will
work exactly the same as the others unless the front panel jacks are employed. This would of course divert the input
from the rear to the front as the front input jacks have been given priority.

All channels feature an input connector that is connected to the source and a thru connector that is normally
connected to the keyboard player’s personal mixer. The XLR output employs the AES standard with pin-1 ground
and pin-2 hot. This is isolated using a Jensen JT-DBE transformer and is connected to the mixer. The XLR output

is a transformer isolated 600 ohm mic level that can drive cables to 500 feet (165
meters) without introducing noise.

It is important to note that the output of the JD6 be microphone level so that it can
run along side mic signals without introducing crosstalk or distortion when passing

through typical mic splitters.

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As such, the output of the JD6 must be connected to the mic
input on a mixer or to a mic pre-amplifier in order to properly
match your levels and impedance. Doing so will provide
optimum sound quality and best overall performance.

True to the Music

5. USING THE JD6

Before connecting the JD6 to your system, ensure all levels
are turned off so that you do not cause connection pops in
your system. All switches should be in the OUT position
when setting up the system. The JD6 is completely passive
and therefore requires no power. Just plug and play . Having
48V phantom on to power condenser microphones or active
direct boxes will not harm the JD6.

Connect the source instrument to the input, your instrument
amplifier or personal mixer to the thru-put and the XLR output
to the main house or recording mixer. If noise is encountered
try lifting the ground. If the level seems high on a particular
channel, engage the –15dB pad. When recording a direct feed,
as well as a microphone feed, try reversing the polarity. This
can lead to some very dramatic results!

To house mixing consol e

From instrument

SWITCHING JACKS

FRON T PA N EL H AS P RI O RIT

To personal mixer

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6. GROUNDING OPTIONS FOR THE SYSTEM
ENGINEER

For pro-touring, the Radial JD6 is outfitted with some very
clever ground schemes. This allows the system integrator,
studio designer or keyboard technician to use several options
to best adapt to his designs for safe and noise-free
performance. As noted earlier, all JD6 channels feature a
separate XLR pin-1 ground lift for each channel. It is
important to note that each channel of the JD6 is also 100%
isolated from each other to eliminate crosstalk and potential
ground problems. This is why all of the input jacks are
isolated.

Inside the JD6 are six additional ground switches (Fig. 1)
that allow the system engineer to bond the circuit ground to
the chassis. Normally, each channel of the JD6 is ‘floating’
whereby each channel acts as if it were a separate or stand­alone direct box. Some system engineers prefer to set-up
alternate ground schemes such as ‘star grounds’ whereby a
single ground point is employed and all channel grounds
are directed to this point. These switches are factory set in
the floating position but may be changed by simply opening
up the JD6 and depressing the chassis ground switch. A
ground lug on the rear panel (Fig 2) would then be used to
bond the JD6 chassis to the rack or a ground bus.

As an added facility, channel-1 features a side access ground
switch (Fig. 3) for system engineers that employs a single
audio channel for chassis ground. This is activated using a
‘tweaker’ or small screwdriver.

True to the Music

Fig. 1 Internal ground switch on each
channel is factory set to “Float”

Fig. 2 A convenient chassis ground is
provided to allow alternate ground schemes

NOTE: Chassis grounding is usually not required with
the Radial JD6 because of the isolating nature of the device
and the extensive ground plane that is employed. Unless
you are a qualified system engineer, we recommend that
these be left in the factory set position. As such, changing
these has purposely been made difficult.

Fig. 3 Channel 1 side access switch
connects chassis ground to pin 1. Factory
set “Out” to “Float”

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7. TYPICAL STAGE SET-UP USING THE RADIAL JD6

The Radial JD6 may be used in a variety of configurations. This common set-up for stage use shows a computer
sound card being connected to channels 1 & 2, keyboards to channels 3 & 4 and sound modules to channels 5 & 6.
Note that the computer could be connected to the front panel ¼” jacks or the RCA jacks should this be more
convenient.

Typical Block Diagram
using Radial JD6 in concert setting

Balanced outputs to hous e mix

To Ra

Samplers

From JD6 to musician’s
pers onal mi xe r

Keyboards

8. TYPICAL STUDIO SET-UP USING THE RADIAL JD6

The Radial JD6 is ideally suited for project studios where some connections are permanent while others may be
fluid. This is where having the switching jacks truly help on channels 1 and 2. For instance, you may wish to
connect an acoustic guitar or bass to your system when laying down a track. By simply connecting to channel 1 or
2 front panel inputs, the connection is diverted from the back to the front without having to reconfigure your studio.

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9. OPTIONAL OUTPUT PANELS

For the hectic life of pro-touring, a choice of hook-up panels is offered to extend the outputs from the Radial JD6 to
the house sound system.

This top figure shows the JD6 with a simple

SWITCHING JACKS

FRONT PANEL HAS PRIORITY

SWITCHING JACKS

FRONT PANEL HAS PRIORITY

SWITCHING JACKS

FRONT PANEL HAS PRIORITY

SWITCHING JACKS

FRONT PANEL HAS PRIORITY

SWITCHING JACKS

FRONT PANEL HAS PRIORITY

SWITCHING JACKS

FRONT PANEL HAS PRIORITY

XLR breakout panel called the JD6-X6. This
comes standard with 3 feet and 6 feet
extensions allowing the breakout panel to be
mounted on the back or the front of the
keyboard rack.

This provides the benefit of making the
connections wherever convenient while
reducing the clutter of cables.

The second JD6-X12 panel is designed for use
when using 12 channels or two JD6’s together
in a rack. A 37-pin multi connector is used in
conjunction with a multi-pin to XLR male
breakout or multi-to-multi. This handy quick­disconnect option accelerates system set-ups
and tear-downs by allowing 12 keyboards
connections to be made with a simple ¼” twist!

The real benefit here is the total elimination
of errors during set-up thus saving tremendous
time on multi-date tours.

10. THE ADVANTAGE OF GOING PASSIVE!

The Radial JD6 is completely passive. This means that it does not require any AC or DC to power the unit to make
it work. You plug in and you are ready to go. High quality Jensen audio transformers are used to bridge the input
to the XLR output. Being 100% passive has many advantages over active devices.

To begin, one must understand how a transformer works. A transformer is made up of a primary coil of wire and a
secondary coil. These are wound around the transformer core. When current is sent through the first coil, a
magnetic field is generated. The magnetic field passes through the core, into the secondary coil where it ‘works
backwards’ and reconverts the magnetic field into current. Because the input (primary) and the output (secondary)
are not electrically connected, problems such as noise, ground loops, and stray voltages are eliminated. This makes
hookup easy and trouble free.

Of course it must be noted that not all transformers are created equal. Just as a good dynamic microphone is only as
good as the capsule, a passive direct box is only as good as the transformer inside. The Radial JD6 employs the
world’s finest Jensen Audio Transformers to ensure the transition from the unbalanced signal to the balanced output
is both smooth and distortion-free. Jensen Transformers are legendary with their warm Bessel curve and their
ability to transfer all frequencies from 10Hz to 40kHz without introducing harmonic or phase distortion. This is
why we use Jensen Transformers exclusively in our professional Radial product line.

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