MasterSounds UNION AUDIO Radius 2 User manual

Radius 2
Operation Manual

Index
1: Safety instructions pg3
2: Overview pg4
3: Front panel controls pg5
4: Rear panel controls pg7
5: Warranty pg9
6: Technical specification pg9
Radius 2
Operation Manual Index 2

1: Important safety instructions - Read rst
READ THE INSTRUCTIONS – Read and retain these instructions for
future reference. Read the instructions on the Safety Sheet provided
separately. Adhere to all warnings printed here and on the console and
its power unit.
COVERS – Do not remove the power unit cover. Operate the console
with its cover correctly fitted. Refer servicing work to authorised
personnel only.
MAINS POWER – Connect the console power unit to a mains power supply
only of the type described in this user guide and marked on the unit.
The power source must provide a good ground connection. Do not remove
or tamper with the ground connection in the power cord. Use the power
cord with sealed mains plug appropriate for your local mains supply
as provided with the console. Route the power cord so that it is not
likely to be walked on, stretched or pinched by items placed upon or
against it.
INSTALLATION – Install the console and its power unit in accordance
with the instructions printed in this user guide. Do not connect
the output of power amplifiers directly to the console. Use audio
connectors and plugs only for their intended purpose.
VENTILATION – nsure adequate ventilation around the console and its
power unit. Do not obstruct the ventilation slots or position the unit
where the air flow required for ventilation is impeded.
MOISTURE – To reduce the risk of fire or electric shock do not expose
the equipment to rain or moisture or use it in damp or wet conditions.
Do not place containers of liquids on it which might spill into any
openings.
ENVIRONMENT – Locate the units away from direct sunlight and any
equipment, which produces heat such as power supplies, amplifiers and
heaters. Protect from excessive dirt, dust, heat and vibration when
operating and storing. Avoid tobacco ash, drinks spillage, and smoke,
especially that associated with smoke machines. Do not mount the power
supply on any surface subject to resonance or vibration.
HANDLING – To prevent damage to the controls and cosmetics avoid
placing heavy objects on the console surfaces, scratching the surface
with sharp objects, or rough handling and vibration. Protect the
controls from damage during transit. Use adequate packing if you need
to ship the unit.
Radius 2
Operation Manual Safety Instructions 3

2: Overview
Originally launched in 2016, the Radius 2 two-channel rotary DJ mixer
became an instant hit with the high-end DJ and club installation
community, followed by the introduction of the Radius 4 four-channel
version, two valve-based versions (Radius Two and Four Valve), an FX
unit and dedicated LinearPOWER supply accessory.
“Four years on, the brand has seen remarkable growth, but the higher
production costs of a premium rotary mixer rules them out for DJs on a
tighter budget. “Designer, Andy Rigby-Jones, and I decided to do something
about it, and the challenge was to redesign the compact Radius 2 and
Radius 4 to make them more affordable but without compromising any of the
features, the feel, or the audio fidelity of the original model,”
explains MasterSounds’ founder, Ryan Shaw.
The new generation Radius 2 and 4 offers clean, open, and dynamic sonic
quality on both LINE and RIAA inputs, as well as improved usability.
Both mixers feature easy-reading analogue VU meters, a responsive Master
EQ/Isolator, a smooth natural sounding hi-pass filter on each channel,
and an AUX send/Return system with insert button for easy integration
of external effects, including MasterSounds own FX unit. Radius 4 also
includes 2 mic inputs, selectable via the rear panel.
“The redesign challenge meant going back to the drawing board to see
where we could simplify the circuitry without impairing performance. For
instance, the Split Composite Passive RIAA stage remains identical to the
previous generation but we have simplified the post-fader circuitry. The
biggest change was to the internal construction and PCB board shapes,
where we have optimised them for maximum efficiency through our in-house
fabrication plant which has made them a lot easier to manufacture. What
we haven’t compromised on is the quality of the components used, and the
third-generation mixers all feature Alps pots/switches, close tolerance
resistors/capacitors, and Panasonic electrolytics. I am very happy with
the result of the engineering changes, and these compact mixers offer
exceptional value for money,” explains Union Audio’s Andy Rigby-Jones.
Union Audio has evolved and experienced some radical changes since
Radius 2’s inception four years ago, which has equipped the team to
implement the design changed. Moving into a new unit in 2017, Rigby-
Jones has developed a sophisticated design and production facility,
coupling traditional analogue engineering with ultra-high specification
manufacturing.
“The Radius 2 and 4 hold a special place in my heart, it’s the mixer Andy
and I began our audio journey with, and one that gives the user a really
unique way of blending records. Both Radius 2 and 4 are desktop products,
with a small footprint, which makes them perfect for home, touring, and
club use, or all three! It was the right time to re-engineer Radius,
giving more DJs the opportunity to experience our wonderful product, at a
price unseen given each mixer’s quality of build and fidelity of sound,”
concludes Shaw.
Radius 2
Operation Manual Overview 4

3: Front panel controls
Radius 2
Operation Manual Front panel controls
AUX – The AUX send level pot adjusts the a mount of channel signal
level sent to the Aux Mix Buss, (and on to an external FX unit). Fully
clockwise the signal level is boosted by +10dBu, allowing for precise
adjustment of FX signals.
PRE – The Pre button switches the Aux send feed from Post Fader to Pre
Fader (i.e. set to Pre Fader it will still send to the Aux Mix Buss with
the rotary fader down).
TRIM – The trim pot adjusts the input signal level from OFF up to a
maximum of +10dBu, enabling accurate level matching between different
musical sources.
LINE/RIAA – This toggle switch selects either the RIAA (Phono) level
Input in its top position, or the LINE Input in the bottom position.
HPF – HPF stands for “High Pass Filter”. The HPF is 12dB per octave and
can be swept from 10Hz to 1.5kHz by turning the rotary pot clockwise.
The HPF is a great performance tool and has been designed to sound
natural, aiding smooth mixing.
CUE – Each cue button routes the channel signal to the headphones, and
displays the channel pre-fade signal level on the VU meters. Pressing
the cue button illuminates the red LED. When no cue button is active
the headphone signal is automatically routed to the Master Mix Buss.
5

CH1/CH2 ROTARY FADER – Each channel has a large rotary fader for
precision control of its level when mixing. The rotary ranges from
fully off when anti- clockwise to unity gain (0dB) when clockwise. For
best performance operate these controls near to their fully clockwise
position for normal music level.
VU METERS – The Radius 2 features two high quality analogue VU (Volume
Unit) meters, which accurately measure the left and right audio signals.
The meters show the post EQ sound level. An added feature of the VU
Meters is that when driven over +6VU the meter will illuminate RED to
warn against clipping. In SPLIT MODE the LEFT VU Meter indicates the
cue signal level, and the RIGHT VU Meter indicates the MIX level, (see
SPLIT below).
MASTER EQ/ISOLATOR – The MASTER EQ /ISOLATOR functions as a normal
isolator using 12dB/octave filters with crossover frequencies at 350Hz
and 3.5kHz making for a very musical Isolator. We have positioned the
layout of the pots so it easily works as a Master EQ (The hi-pass filters
on each channel are used instead of a conventional 3 or 4 band EQ).
MASTER – The MASTER rotary pot adjusts the signal level sent to the Main
Output XLRs (House Mix) ranging from off to +10dBu of gain. Set the
control to approximately 1 o’clock for unity.
BOOTH – The BOOTH rotary pot adjusts the signal level sent to the Booth
Output TRS Jacks (Monitor Mix) ranging from off to +10dBu of gain. Set
the control to approximately 1 o’clock for unity.
SPLIT – The SPLIT CUE button illuminates RED when activated and links
to the cue Buttons and VU Meters. When the SPLIT CUE is active and a
channel CUE is pressed, the Mix Buss Level will be shown on the Right
Meter, and the channel Pre-Fade signal (CUE) shown on the Left Meter,
enabling you to balance the two levels for smoother mixing. The Split
button also sends the cued source to the Left headphone and the mix
source to the Right headphone which is very useful if mixing in a quiet
environment. SPLIT CUE is automatically disabled when the Channel CUEs
are Off, and the Meters and Headphones revert to monitoring the Stereo
Master Mix Signal.
PHONES – Use the headphone pot to control the sound level sent to
your headphones. Please take care when monitoring with headphones as
excessive sound volumes can cause premature deafness. The 1⁄4” jack
headphone input is located on the front of the mixer as shown on the
headphone graphic.
Radius 2
Operation Manual Front panel controls 6

Radius 2
Operation Manual Rear panel controls 7
4: Rear panel controls
MASTER OUT – Output level is +14dBu when the MASTER level control is
fully clockwise and the VU meters read -4VU. The XLR output is designed
to operate with balanced equipment such as powered monitor speakers and
amplifiers.
AUX SEND & RETURN/INSERT – The AUX SEND & AUX RETURN system has ¼” TRS
(balanced) jack sockets for connection to an external FX unit. The SEND
is connected to the FX units’ input, and the FX units’ output is connected
to the RETURN, (see USING THE EXTERNAL SEND & RETURN SYSTEM).
INSERT ON BUTTON – Reconfigures the Aux Return Jacks as a Mix Buss Insert,
giving the user unparalleled flexibility for FX integration, simply at
the press of a button. (See USING THE EXTERNAL SEND & RETURN SYSTEM).
GROUND POST – Unscrew the knurled nut and attach the turntable(s) ground
lead(s) and screw back into place without over tightening the nut.
RECORD OUT – Twin RCA sockets enables the user to make a stereo recording
of a performance. The overall volume of the Master Output does not affect
the record out function, this outputs at -6dBu
BOOTH OUT – The ¼” TRS (balanced) Jack Booth Output feeds the DJ’s booth
(local Monitor) amplifier/loudspeaker system.
POWER SWITCH – “O” = OFF. Press the “–” to power the mixer ON with the
external power supply connected.
POWER INPUT SOCKET – Connect the external 18v power supply to the input
socket as labelled on the rear panel. CH ONE/CH FOUR – Both LINE and PHONO
inputs feature twin (Left & Right).
CH ONE/CH FOUR – Both LINE and PHONO inputs feature twin (Left & Right)
RCA Phono Sockets. The PHONO input provides gain and RIAA equalisation
for turntable cartridges. The LINE inputs on CH1 & CH2 provide input for
CD players.

Radius 2
Operation Manual Rear panel controls 8
Using the external Send & Return System
Connect the Mixer Aux Send outputs to the FX unit Inputs, and connect
the FX units Outputs to the mixer Aux Returns. Set the FX unit to
unity gain.
Turning up the mixer Channel Send control feeds the channel signal to
the FX unit. This signal is processed by the FX unit and its output
is fed back into the mix, adding an echo, delay, reverb etc. to the
track that’s playing. Turning down the Mixer channel send stops the
channel signal feeding to the FX unit and so also stops the effect.
Turning up the mixer channel send increases the level of FX.
Normally the feed to the channel Aux send is also controlled by the
channel fader, so turning down the fader also turns down the level of
FX, but if the Aux Send PRE button is pressed the Aux send takes its
signal before the Channel Fader so even if the fader is off you can
still send the channel signal to the FX Unit. This can be quite a cool
way to mix into a new track, just by introducing a low level delay
(for instance) of the track you about to mix into, before actually
mixing in the new track by bringing up the channel fader.
Mix Insert – The Radius 2 incorporates a unique feature that allows
the Aux Return Jack Sockets to be reconfigured as a Mix Buss Insert
point, just by pressing the INSERT ON button. This allows you to run
the entire mix though an external FX processor or other devices,
such as a compressor, limiter, or graphic equaliser. With the button
pressed the two 1⁄4” TRS Jacks become a conventional mixer Insert,
with the Tip being the SEND, and the Ring being the Return.

Radius 2
Operation Manual Warranty 9
5: Warranty
MasterSounds warrants that the Mixer shall be free of defects in
workmanship and materials for a period of twenty four months (2 years)
from the date of delivery. In the event that the product fails to
operate as intended, MasterSounds will repair or replace the product
subject to the following conditions.
That the failure was not due to improper installation, operation,
cleaning or maintenance, accident, damage, misuse, abuse, or non-
approved modifications to the Mixer.
The warranty does not cover normal wear and tear or any other event,
act, default or omission outside MasterSounds control.
Faulty products must be returned to MasterSounds or an authorised
service agent along with the original invoice or proof of purchase,
and the mixer must be returned packed in the original shipping box.
Please contact MasterSounds before shipping a faulty unit.
The warranty applies only to the original purchaser and is not
transferrable.
At their sole discretion, MasterSounds may either repair the defective
product or replace with an equivalent service exchange item.
This warranty constitutes the purchaser’s sole remedy. MasterSounds
shall not be liable for any other repair or replacement cost or any
damage or loss directly or indirectly related to the malfunction of
this mixer.
1.
2.
3.
4.
5.
6.
MasterSounds Radius 2 complies with the European
Electromagnetic Compatibility directives
2014/30/EU and the European Low Voltage
directives 2014/35/EU.

www.mastersounds.co.uk
Radius 2 Operation Manual
Copyright © 2020 MasterSounds Audio. All rights reserved 10
6: Technical specication
Power Requirement
Each mixer is supplied with a compact switch-mode power supply for anywhere
in the world and we supply the correct IEC lead for your country.
External Power Supply
DC Internal Power Rails
Audio Performance
Residual Output Noise
Mix noise Unity Line IN to Mix Out
Distortion THD+N 0dBu
Distortion THD+N +10dBu
Dynamic Range
Maximum Signal Level
Frequency Response
Headphone Output Power
EQ/Filters
Channel High-Pass Filter Range
Master EQ/Isolator Cut/Boost
Master EQ/Isolator Crossover
RIAA Accuracy
Dimensions
Weight
Packed Dimensions
Packed weight
Dimensions
Weight
Packed Dimensions
Packed weight
** MasterSounds reserves the right to change the specification without notice. **
Universal 90V – 265V AC 50/60Hz
18V 18W Max
+/- 18V DC
<-95dBu 20Hz to 20kHz un-weighted
<-88bBu 20Hz to 20kHz un-weighted
= 0.0025% Line IN to Mix OUT
= 0.0001% Line IN to Mix OUT
>115dB
±27dBu
10Hz – 100kHz +0.5/-2dB
800mW RMS into 32 Ohms
10Hz to 1.5kHz
OFF to +12dB
Fc 350Hz and 3.5kHz
Within 0.25dB 40Hz – 20kHz.
W = 230 L = 190 H = 83 (mm)
2.5KG
W = 350 L = 260 H = 180 (mm)
3.2KG
W = 9 L = 7.5 H = 3 (inch)
5.5lb
W = 14 L = 10 H = 7 (inch)
7lb

Universal 90V – 265V AC 50/60Hz
18V 18W Max
+/- 18V DC
<-95dBu 20Hz to 20kHz un-weighted
<-88bBu 20Hz to 20kHz un-weighted
= 0.0025% Line IN to Mix OUT
= 0.0001% Line IN to Mix OUT
>115dB
±27dBu
10Hz – 100kHz +0.5/-2dB
800mW RMS into 32 Ohms
10Hz to 1.5kHz
OFF to +12dB
Fc 350Hz and 3.5kHz
Within 0.25dB 40Hz – 20kHz.
W = 230 L = 190 H = 83 (mm)
2.5KG
W = 350 L = 260 H = 180 (mm)
3.2KG
W = 9 L = 7.5 H = 3 (inch)
5.5lb
W = 14 L = 10 H = 7 (inch)
7lb

Radius 2 Operation Manual
Copyright © 2020 MasterSounds Audio. All rights reserved
www.mastersounds.co.uk