Allen&Heath WZ 20S USER GUIDE

ALLEN&HEATH

MixWizard Series

WZ20S

Stereo Audio Mixing Console

USER GUIDE

Publication AP3634

Limited One Year Warranty

This product has been manufactured in the UK by ALLEN & HEATH and
is warranted to be free from defects in materials or workmanship for
period of one year from the date of purchase by the original owner.

To ensure a high level of performance and reliability for which this
equipment has been designed and manufactured, read this User Guide
before operating.

In the event of a failure, notify and return the defective unit to ALLEN &
HEATH or its authorised agent as soon as possible for repair under
warranty subject to the following conditions

Conditions Of Warranty

1. The equipment has been installed and operated in accordance with
the instructions in this User Guide

2. The equipment has not been subject to misuse either intended or
accidental, neglect, or alteration other than as described in the User
Guide or Service Manual, or approved by ALLEN & HEATH.

3. Any necessary adjustment, alteration or repair has been carried out
by ALLEN & HEATH or its authorised agent.

4. The defective unit is to be returned carriage prepaid to ALLEN &
HEATH or its authorised agent with proof of purchase.

5. Units returned should be packed to avoid transit damage

These terms of warranty apply to UK sales. In other territories the terms
may vary according to legal requirements. Check with your ALLEN &
HEATH agent for any additional warranty which may apply.

WZ20S User Guide AP3634 Issue 2.

Copyright © 2001 Allen & Heath Limited. All rights reserved

Manufactured in the United Kingdom by

Allen & Heath Limited
Kernick Industrial Estate, Penryn, Cornwall, TR10 9LU, UK

http://www.allen-heath.com

ALLEN&HEATH

2 WZ20S User Guide

Important Safety Instructions

WARNINGS - Read the following before proceeding :

CAUTION

ATTENTION: RISQUE DE CHOC ELECTRIQUE – NE PAS OUVRIR

Read instructions: Retain these safety and operating instructions for future reference.

Adhere to all warnings printed here and on the console. Follow the
operating instructions printed in this User Guide.

Do not remove covers: Operate the console with its covers correctly fitted. Disconnect mains

power by unplugging the power cord if the covers need to be removed
for setting internal options. Refer this work to competent technical
personnel only.

Power sources: Connect the console to a mains power only of the type described in

this User Guide and marked on the rear panel. Use the power cord
with sealed mains plug appropriate for your local mains supply as
provided with the console. If the provided plug does not fit into your
outlet consult your service agent for assistance.

Grounding: Do not defeat the grounding and polarisation means of the power cord

plug. Do not remove or tamper with the ground connection in the
power cord. This equipment must be grounded (earthed).

Power cord routing: Route the power cord so that it is not likely to be walked on, stretched

or pinched by items placed upon or against it.

Water and moisture: To reduce the risk of fire or electric shock do not expose the console

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.

Ventilation: Do not obstruct the ventilation slots or position the console where the

air flow required for ventilation is impeded. If the console is to be
operated in a rack unit or flightcase ensure that it is constructed to
allow adequate ventilation.

Heat and vibration: Do not locate the console in a place subject to excessive heat or

direct sunlight as this could be a fire hazard. Locate the console away
from any equipment which produces heat or causes excessive
vibration.

Servicing: Switch off the equipment and unplug the power cord immediately if it

is exposed to moisture, spilled liquid, objects fallen into the openings,
the power cord or plug become damaged, during lightening storms, or
if smoke, odour or noise is noticed. Refer servicing to qualified
technical personnel only.

Installation: Install the console 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.

WZ20S User Guide 3

Important Mains plug wiring instructions.

The console is supplied with a moulded mains plug fitted to the ac
mains power lead. Follow the instructions below if the mains plug has
to be replaced.

The wires in the mains lead are coloured in accordance with the
following code:

TERMINAL

European USA/Canada

LIVE BROWN BLACK

L

NEUTRAL BLUE WHITE

N

EARTH GND GREEN & YELLOW GREEN

E

If the colours of the wires in the mains lead do not correspond with the
coloured markings identifying the terminals in your plug, proceed as
follows:

The wire which is coloured Green and Yellow must be connected to
the terminal in the plug which is marked with the letter E or with the
Earth symbol.

The wire which is coloured Blue must be connected to the terminal in
the plug which is marked with the letter N.

The wire which is coloured Brown must be connected to the terminal
in the plug which is marked with the letter L.

Ensure that these colour codes are followed carefully in the event of
the plug being changed.

WIRE COLOUR

WARNING: This appliance must be earthed.

Mains electricity is dangerous and can kill. Mains voltage is
present within the console. Do not remove the covers with mains
electricity connected. Mains earth is connected to the console
chassis through the power lead to ensure your safety. Do not
remove this mains earth connection.

This product complies with the European Electromagnetic
Compatibility directives 89/336/EEC & 92/31/EEC and the
European Low Voltage Directives 73/23/EEC & 93/68/EEC.

Any changes or modifications to the console not approved by Allen &
Heath could void the compliance of the console and therefore the
users authority to operate it.

4 WZ20S User Guide

Introduction

ALLEN & HEATH continues its commitment to provide high quality audio mixing
equipment engineered to meet the exacting requirements of today’s audio business. The
WZ20S compact stereo mixing console brings you the latest in high performance
technology and offers the reassurance of over two decades of console manufacture and
customer support.

This user guide presents a quick reference to the function and application of the WZ20S.
We recommend that you read this fully before starting. Included is information on
installing, connecting and operating the console, panel drawings and technical
specification. A system block diagram is printed on the rear cover. For further information
on the basic principles of audio system engineering, please refer to one of the specialist
publications available from bookshops and audio equipment dealers.

Whilst we believe the information in this guide to be reliable we do not assume
responsibility for inaccuracies. We also reserve the right to make changes in the interest
of further product development.

Service And Technical Support

We are able to offer further product support through our world-wide network of approved
dealers and service agents. You can also access our Web site on the Internet for
information on our product range, assistance with your technical queries or simply to chat
about matters audio. To help us provide the most efficient service please keep a record
of your console serial number, and date and place of purchase to be quoted in any
communication regarding this product. The serial number is located on the connector
panel. A space is provided here for you to note this.

Console SERIAL NUMBER Date of purchase Place of purchase

Looking After Your Console

Your WZ20S is ruggedly constructed and should provide many years of reliable service
whether installed, location mixing or live gigging. However, you will extend the life of the
console and preserve its appearance by applying these simple common sense
precautions:

Damage : To prevent damage to the controls and cosmetics avoid placing heavy objects
on the control surface, scratching the surface with sharp objects, or rough handling and
vibration.

Environment : Protect from excessive dirt, dust, heat and vibration when operating and
storing. Avoid tobacco ash, smoke, drinks spillage, and exposure to rain and moisture. If
the console becomes wet, switch off and remove mains power immediately. Allow to dry
out thoroughly before using again.

Cleaning : Avoid the use of chemicals, abrasives or solvents. The control panel is best
cleaned with a soft brush and dry lint-free cloth. The faders, switches and potentiometers
are lubricated for life. The use of electrical lubricants on these parts is not recommended.

Transporting : The console may be transported as a free-standing unit or mounted in a
rack or flightcase. Ensure that the connector pod is secured in place with the locking
screws fitted to prevent movement. Protect the controls from damage during transit. The
faders are best positioned at the top of their travel if the console is transported without a
suitable flightcase, rack or carton. Use adequate packing if you need to ship the unit.

WZ20S User Guide 5

Overview of the MIXWIZARD WZ20S

The WZ20S is a compact audio mixing console with many stereo inputs. It is well suited
to mixing stereo sources such as keyboards, voice modules and effects returns, or for
recording or stage submixing. With its additional mic inputs it is also equipped for low
end broadcast, club installation and production mixing. The WZ20S complements the
MixWizard range which also includes the multi mic input WZ12DX and WZ16DX with built
in effects processors, and the WZ14:4:2+ which is dual function 4 buss live mixer.

The WZ20S has 12 input channel strips. Four mono channels accept any signal, mic or
line, on either jack or XLR. Eight stereo strips feature dual A and B inputs so that one of
two stereo sources can be selected, or they can be mixed together with individual control
of gain. This allows permanent connection of 16 stereo sources. Inputs A are on phono
pin jacks and inputs B on TRS jacks. An optional RIAA card can be fitted to the phono
inputs. The jack inputs are balanced and normalled for use with stereo or mono sources.
An additional two stereo external inputs are available and can be configured as returns to
the mix or as external inputs for monitoring only.

The mono channels provide 4 band EQ with shelving high and low, and two parametric
mid bands. The stereo channels provide 4 band EQ with shelving high and low, and two
fixed frequency mid bands. All equalisers include in/out switching.

The WZ20S provides two independently assignable stereo mix busses MIX1 and MIX2.
Each feeds a pair of balanced XLR outputs together with inserts and metering. In
addition, MIX2 includes a second stereo output on TRS jacks and a summing mono
output on balanced XLR. Mix1 can be assigned to feed MIX2 to provide a stereo
subgroup if required. 6 independent aux outputs on TRS jacks include pre/post switching
in groups of two and four. This flexible output scheme satisfies many applications
including dual stereo submixing, stereo and mono broadcast and amplifier feeds,
cleanfeed sends, zone and recording feeds.

A unique combination of monitoring features is provided to satisfy the specific
requirements of live mixing, broadcast and club install. Dedicated headphones and local
monitor outputs include separate level control. A large switch bank lets you select any
output for monitoring, automatically overriden by channel PFL selection. Two
headphones can be connected, one on the top panel, one on the rear, for example in a
presenter/guest situation. The local monitor feeds separate TRS jacks and includes mute
(internally configurable for 20dB dim) and PFL enable facilities. Split PFL can be
selected to keep the output program in the right ear while monitoring the PFL channel in
the left, ideal for broadcast or club booth monitoring. A switch allows instant checking of
the stereo signal for mono compatibility.

In keeping with the rest of the range, the WZ20S offers the QCC (Quick Change
Connector) rotating pod which can be set for 8U high 19” rack or rear connector desktop
operation. 100mm faders and professional build quality using individual channels with
nutted pots and all steel chassis provide solid reliability and easy servicing. The internal
power unit is an efficient switched mode design which allows universal connection to the
most common world wide mains voltages.

The layout is simple and intuitive and includes tamperproof underpanel switches for
configurable functions, important for broadcast and club applications.

There are several internal configuration options to further customise the console for more
specialist applications. These include aux pre/post and mono/stereo links, SYS-LINK
expander output card, RIAA preamp cards, optional switched faders for remote start/stop,
local monitor auto dim from fader or switch, and custom wiring to 25pin D connector.
These options should be configured by competent service or installation personnel. For
further details please contact your ALLEN & HEATH agent.

Finally, in keeping with the ALLEN & HEATH design philosophy, the WZ20S carries
forward the sonic purity of analog MSP (Minimum Signal Path) engineering to ensure the
very best audio performance.

6 WZ20S User Guide

Front Panel Layout

For clarity only the first two stereo channels are shown.

MixWizard

PAD

-30dB

40

30

GAI N

50

PAD

20

- 10

60 30

100Hz

0

HF

12kHz

-15

+15

3kHz

1k

5k

7k

700

15kHz

500Hz

0

MF1

-15

+15

180Hz

60

300

45

450

35Hz

1kHz

0

MF2

-15

+15

0

LF

60Hz

-15

+15

EQ
IN

AUX

1

0

OO

+6

AUX

2

0

OO

+6

AUX

3

0

OO

+6

AUX

4

0

OO

+6

POST

PRE

AUX

5

0

OO

+6

AUX

6

0

OO

+6

POST

PRE

PAN

L

R

ON

PEAK

!

PFL

10

MIX1

5

MIX2

0

-30dB

30

GAI N

PAD

20- 10

0

HF

12kHz

-15

3kHz

1k

700

500Hz

0

MF1

-15
180Hz

60

45

35Hz

0

MF2

-15

0

LF

60Hz

-15

EQ
IN

AUX

1

OO

AUX

2

OO

AUX

3

OO

AUX

4

OO

AUX

5

OO

AUX

6

OO

PAN

L

PEAK

!

PFL PFL PFL PFL PFL

10

MIX1

MIX2

5

0

10

GAI N

-5

PAD

40

50

60 30

100Hz

+15

5k

7k

15kHz

+15

300

450

1kHz

+15

+15

0

+6

0

+6

0

+6

0

+6

POST

PRE

0

+6

0

+6

POST

PRE

R

ON

5

0

PAD

-30dB

40

30

GAI N

50

PAD

20- 10

60 30

100Hz

0

HF

12kHz

-15

+15

3kHz

5k

1k

7k

700

15kHz

500Hz

0

MF1

-15

+15

180Hz

60

300

45

450

35Hz

1kHz

0

MF2

-15

+15

0

LF

60Hz

-15

+15

EQ
IN

AUX

1

0

OO

+6

AUX

2

0

OO

+6

AUX

3

0

OO

+6

AUX

4

0

OO

+6

POST

PRE

AUX

5

0

+6

OO

AUX

6

0

OO

+6

POST

PRE

PAN

L

R

ON

PEAK

!

10

MIX1

5

MIX2

0

PAD

-30dB

40

30

GAI N

50

PAD

20- 10

60 30

100Hz

0

HF

12kHz

-15

+15

3kHz

5k

1k

7k

700

15kHz

500Hz

0

MF1

-15

+15

180Hz

60

300

45

450

35Hz

1kHz

0

MF2

-15

+15

0

LF

60Hz

-15

+15

EQ
IN

AUX

1

0

OO

+6

AUX

2

0

OO

+6

AUX

3

0

OO

+6

AUX

4

0

OO

+6

POST

PRE

AUX

5

0

+6

OO

AUX

6

0

OO

+6

POST

PRE

PAN

L

R

ON

PEAK

!

10

MIX1

5

MIX2

0

15

20

-10

ON

5

0

10

GAI N

-5
15

-10

20

ON

MONO

0

HF

12kHz

-15

+15

0

MF1

-15

+15

0

MF2

-15

+15

0

LF

60Hz

-15

+15

EQ
IN

AUX

1

0

OO

+6

AUX

2

0

OO

+6

AUX

3

0

O4O

+6

AUX

0

OO

+6

POST

PRE

AUX

5

0

OO

+6

AUX

6

0

OO

+6

POST

PRE

BAL

L

R

ON

PEAK

!

10

MIX1

5

MIX2

0

5

5

0

10

GAI N

-5
15

20

-10

ON

5

0

10

GAI N

-5
15

-10

20

ON

MONO

0

HF

12kHz

-15

+15

0

MF1

-15

+15

0

MF2

-15

+15

0

LF

60Hz

-15

+15

EQ
IN

AUX

1

0

OO

+6

AUX

2

0

OO

+6

AUX

3

0

O4O

+6

AUX

0

OO

+6

POST

PRE

AUX

5

0

OO

+6

AUX

6

0

OO

+6

POST

PRE

BAL

L

R

ON

PEAK

!

10

MIX1

5

POWER ON

MIX1

MIX2

EXT1
IN

O

O

+16

+9

+6

+3

0

-6

-9 -9

-16

-20

-30

MIX1

AUX

1

O

O

AUX

2

O

O

AUX

3

O

O

AUX

4

O

O

AUX

5

O

O

AUX

6

OO

MIX2

10

5

RL

+6

+4

+4

+4

+4

+4

+4

SPLIT
PFL

MONO

EXT2
IN

0

0

1-2

0

0

3-4

0

5-6

0

0

1

MIX2

0

+6

OO

PRG

PFL

SPLIT PFL

+16

+9

+6

+3

0

-3-3

-6

-12-12

-16

-20

-30

L

R

MONITOR

PFL

5

4

6

LEV

3

7

2

8

1

9

010

1

AUX1

AUX2

2

AUX3

3

AUX4

4

AUX5

5

AUX6

6

EXT1

EXT2

ALL UP =

MIX2

MIX1

PFL ENABLE

5

4

6

LOCAL

3

7

MONITOR

2

8

1

9

1

0

0

DIM

MIX2MIX1

10

5

MIX2

0

5

00

5

5

10

10

10

10

10

10

10 10

WZ20S

20

30

OO

20

30

OO

20

30

OO

20

30

OO

DUAL
STEREO

20

30

OO

WZ20S User Guide 7

DUAL
STEREO

20

30

OO

20

30 30

OO OO

20

Rear Panel Layout

MIX 2

L

OUT

R

MIX2

OUT

R

L

INSERT

R

MIX1

LL

OUT

R

M

2

TIP = L
RING = R

A DIVI SION OF HARMAN I NTERNATIONAL I NDUSTRIES Lt d.

L

LOCAL MONITOR

R

Made in the UK by ALLEN & HEATH

MIX 1

L

19-20 17- 18 15-16

INSERT

A

IN

L

R

R

B

IN

M

L /

R

6

5 4

AUX

AUX

EXT I N 2

SYS-LI NK OUT

(option)

AUX

L

R

INA

IN

INA

L

R

B

L /

R

L

R

B

IN

M

M

L /

R

2

3

AUX

AUX AUX

EXT IN 1

L

R

REMOTE

(user connec tions)

STEREO INPUTS

13-14 11- 12

INA

L

R

B

IN

M

L /

R

SENDS

1

XLR OUT

2

1

+OUT

3

- OUT

TIPTIP +

LINE
IN/OUT

IMPEDANCE BALANCED

INSERT

SEND

TIPTIP

RINGRING

RETURN

MixWizard

SERIAL No:

MONO INPUTS

9-10 7-8 5-6

INA

IN

RINGRING -

INA

L

R

B

IN

M

L /

R

+IN

1

2

- IN

3

INPUT

INA

L

R

B

IN

M

L /

R

TIPTIP + IN

RING -INRING

20SWZ

INA

L

R

B

L /

R

TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK
DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE.

WARNING: FOR CONTINUED PROTECTION AGAINST RI SK OF FIRE

ATTENTION: REMPL ACER LE FUSIBLE AVEC UN DES MEMES CARACTERISTI QUES.

L

R

B

IN

M

M

L /

R

CAUTION

AVIS: RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIR.

100 - 240V~ T500mA 250V 20mm

REPLACE FUSE WITH SAME TYPE AND RATING

INSERT

IN

DIR
OUT

4

FUSE

3

INSERT

IN

DIR

OUT

34

MIC 4
+ 48V

MIC 3
+48V

WARNING - THIS APPARATUS MUST BE EARTHED.

AC MAINS IN ~

XLR connections are Pin 2 = hot (+) Pin 3 = cold (-) Pin 1 = GND

TRS input and output connections are Tip = hot (+) Ring = cold (-) Sleeve = GND

TRS insert connections are Tip = SEND Ring = RETURN Sleeve = GND

INSERT

IN

2

INSERT

IN

1

2 134

2

DIR
OUT

1

PHANTOM POWER

MIC 2
+ 48V

SUPPLY VOLTAGE RANGE:

100 - 240V

47-63Hz ~ 30W MAX

MIC 1
+ 48V

~

DIR
OUT

REFER TO USER GUIDE BEFORE CONNECTING SUPPLY
NO USER SERVICEABLE PARTS INSIDE.
REFER SERVI CI NG TO QUAL IF IED S ERVICE P ERSONNEL.

ONOFF

Input Connections

MONO IN (XLR) Balanced XLR female 2k ohm -60 to –20dBu PAD out

>10k ohm -30 to +10dBu PAD in

MONO IN (TRS) Balanced TRS jack >10k ohm -30 to +10dBu

STEREO IN A RCA phono >10k ohm -20 to +10dBu

STEREO IN B Balanced TRS jack >10k ohm -20 to +10dBu

EXT IN 1,2 Balanced TRS jack >10k ohm -10dBV (+4dBu option)

Inserts

MONO Channel Unbalanced TRS jack SEND <75 ohm 0dBu

RETURN >3k ohm

MIX OUT 1,2 Unbalanced TRS jack SEND <75 ohm -2dBu

RETURN >7k ohm

Output Connections

DIR OUT 1-4 Impedance balanced TRS jack <75 ohm 0dBu

MIX OUT 1,2 (XLR) Balanced XLR male <75 ohm +4dBu

MIX OUT 2 (TRS) Impedance balanced TRS jack <75 ohm -2dBu

MONO OUT Balanced XLR male <75 ohm +4dBu

AUX OUT 1-6 Impedance balanced TRS jack <75 ohm -2dBu

HEADPHONES 1,2 Tip = L Ring = R 30 to 600 ohm recommended

8 WZ20S User Guide

Specifications

0dBu = 0.775 Volts rms +4dBu = 1.23V rms

0dBV = 1 Volt rms -10dBV = 316mV rms

Console Specifications

Maximum output level XLR +26dBu into >2k ohm load

TRS jack +21dBu into >2k ohm load

Internal headroom Channels +21dB

Mix to output +23dB

Peak indicators Turn on 5dB before clipping

Meters MIX 1,2 / MONITOR Peak reading 12 led 3 colour

Frequency response +0/-1dB 20Hz to 50kHz

Distortion < 0.006% THD+noise measured at +14dBu 1kHz

Crosstalk < 90dB Channel shutoff measured at 1kHz

Noise Measured rms 22Hz to 22kHz

MIC EIN -128dB referred to 150 ohm source

Residual output noise XLR -90dBu (-94dB S/N)

TRS jack -94dBu (-94dB S/N)

Mix noise, ch routed XLR -86dBu (-90dB S/N)

TRS jack -90dBu (-90dB S/N)

Power Supply

Internal switch mode power unit with auto sensing mains input.

MAINS IN socket IEC 3 pin

Power lead Country dependent with moulded mains plug supplied

AC mains 100 to 240V AC @ 50/60Hz

Consumption 35W max

Mains fuse rating 100-240V AC T500mA 20mm

Dimensions and Weights

The connector pod can be rotated and fixed in one of two positions to allow either
desktop operation with rear facing connectors, or 19” rack mounting with underside
connectors in 10U space.

Width Height Depth

Desktop 483mm (19”) 192mm (7.6”) 530mm (20.9”)

Rack mounted 483mm (19”) 444mm (17.5”) 10U 135mm (5.3”)

Packed 590mm (23.2”) 260mm (10.2”) 610mm (24”)

Unpacked Packed

Weight 10kg (22lbs) 13kg (29lbs)

WZ20S User Guide 9

Installing the Console

The MixWizard Series features the ALLEN & HEATH Quick Change Connector (QCC)
system. The rear connector pod may be hinged and locked into either of two positions.
Rear connectors allow desktop operation with the control panel sloped at a convenient 15
degrees. Underside connectors allow 19" rack mounting in a compact 10U space. The
connector position can be easily changed at any time to fit your application.

To change the
position remove the
crosshead locking
screw on each side,
swing the connector
pod into position, and
refit the two screws

19” Rack Mounting

Desktop Operation

PRECAUTION :

Do not transport or carry the
console with the locking screws
removed.

Do not attempt to remove the
connector pod from the console.

Mount the console in the
rack using 4x M6 bolts
each side for maximum
strength. We recommend
you fit the bolts with plastic
cup washers to protect the
panel, and they look
good... These should be
available from the supplier
of the rack unit or good
hardware store.

Flightcasing

The console can be easily
flightcased in either
connector mode. Provide
the dimensions shown here
to your flightcase supplier.

The console is fitted with
rubber feet to ensure it does
not slip or scratch the work
surface. The control panel
is angled at 15 degrees for
operating convenience.

10 WZ20S User Guide

Connecting Mains Power

TO REDUCE T HE RIS K OF FI RE OR ELECTRI C SHOCK
DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE.

CAUTION

AVIS: RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIR.

100 - 240V~ T500mA 250V 20mm

WARNING: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE

REPLACE FUSE WITH SAM E TYPE AND RATING

ATTENTION: REMPLACER LE FUSIBL E AVEC UN DES MEMES CARACTERISTIQUES.

Earthing

The connection to earth (ground) in an audio system is important for two reasons:

For safety it is important that all equipment earths are connected to mains earth so that
exposed metal parts are prevented from carrying high voltage which can injure or even
kill the operator. It is recommended that the sound engineer check the continuity of the
safety earth from all points in the system including microphone bodies, guitar strings,
connector cases, equipment panels and so on.

The same earth is also used to shield audio cables from external interference such as the
hum fields associated with power transformers, lighting dimmer buzz, and computer
radiation. Problems arise when the signal sees more than one path to mains earth. An
‘earth loop’ (ground loop) results causing current to flow between the different earth
paths. This condition is usually detected as a mains frequency audible hum or buzz.

To ensure safe and trouble-free operation we recommend the following:

WARNING - THIS APPARATUS MUST BE EARTHED.

SUPPLY VOLTAGE RANGE:

100 - 240V

47-63Hz ~ 30W MAX

OFF

FUSE

AC MAINS IN ~

REFER TO U SER GUI DE B EFORE CONN ECTI NG SUP PLY
NO USER SERVI CEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

1. SAFETY - To protect the operator from high voltage shock, and

2. AUDIO PERFORMANCE - To minimise the effect of earth
(ground) loops which result in audible hum and buzz, and to
shield the audio signals from interference.

Read the SAFETY INSTRUCTIONS printed at
the front of this User Guide. Check that the
correct mains lead with moulded plug has been
supplied with your console. The power supply

~

accommodates mains voltages within the range
100-240V without changing any fuses or settings.

ON

It is standard practice to turn connected power
amplifiers down or off before switching the
console on or off. Ensure that the IEC mains
plug is pressed fully into the rear panel socket
before switching on.

• Have your mains system checked by a qualified electrician. If the supply earthing
is solid to start with you are less likely to experience problems.

• Do not remove the earth connection from the console mains plug. The console
chassis is connected to mains earth through the power cable to ensure your safety.
Audio 0V is connected to the console chassis internally. If problems are encountered
with earth loops operate the audio ‘ground lift’ switches on connected equipment
accordingly, or disconnect the cable screens at one end, usually at the destination.

• Use low impedance sources such as microphones and line level equipment rated at
200 ohms or less to reduce susceptibility to interference. The console outputs are
designed to operate at very low impedance to minimise interference problems.

• Use balanced connections where possible as these provide further immunity by
cancelling out interference that may be picked up on long cable runs. To connect an
unbalanced source to a balanced console input, link the cold input (XLR pin 3 or jack
ring) to 0V earth (XLR pin 1 or jack sleeve) at the console. To connect a balanced
console output to an unbalanced destination, link the cold output to 0V earth at the
console.

• Use good quality cables and connectors and check for correct wiring and reliable
solder joints. Allow sufficient cable loop to prevent damage through stretching.

• If you are not sure ... Contact your service or local Allen & Heath agent for advice.

WZ20S User Guide 11

Plugging Up The System

The MixWizard WZ20S uses professional grade 3 pin XLR, 1/4" TRS jack and RCA
PHONO sockets. To ensure best performance, we recommend that you use high quality
audio cables and connectors, and take time to check for reliable and accurate cable
assembly. It is well known that most audio system failures are due to faulty
interconnecting leads. The following mating plugs may be used to connect audio signals
to the console:

All input and output XLR connectors are 3 wire differentially balanced. These have 3
connector pins: Pin 1 = ground (screen), Pin 2 = signal hot (+), Pin 3 = signal cold (-).

All the jack sockets are the 3 pole TRS type. These are wired to work with both the
balanced TRS or the unbalanced 2 pole TS type plugs. The sockets have 3 connector
pins: Inputs and outputs are Tip = signal hot (+), Ring = signal cold (-), Sleeve = ground
(screen). Insert connections are Tip = send, Ring = return, Sleeve = ground.

The RCA phono connectors are the 2 wire unbalanced type typical of those found on
domestic or semi-professional equipment such as CD players.

Avoid reversing + and - on balanced connections as this will result in out of phase signals
(reverse polarity) which may cause signal cancellation effects.

For live work where long cables runs are required, balanced interconnections should be
used. However, interconnections between more affordable 2-wire (signal, ground)
unbalanced equipment and the console are unlikely to cause problems if the cables are
kept short. Refer to the following diagram for unbalanced to balanced connections.

Dealing with Ground Loops, Buzz and Interference

For optimum performance all audio signals should be referenced to a solid, noise-free
ground (earth) point, frequently referred to as the ‘star point’ or ‘clean earth’.

A ground loop is created when the signal has more than one path to ground. Should you
experience hum or buzz caused by ground loops, check first that each piece of
equipment has its own separate path to ground. If so, operate ground lift switches on
connected equipment in accordance with the instruction manuals. Alternatively
disconnect the cable screen at the destination end only. This breaks the offending loop
while still maintaining the screening down the length of the cable.

WARNING For your safety do not remove the ground (earth) connection in the

power lead of the console or connected equipment.

To avoid interference pickup keep audio cables away from mains power units and cables,
thyristor dimmer units or computer equipment. Where this cannot be avoided, cross the
cables at right angles to minimise interference.

12 WZ20S User Guide

Connecting the Mono Channel

4

INSERT

IN

4

DIR

OUT

4

MIC 4

+ 48V

INPUT The input provides both an XLR and a TRS jack connector. The XLR is
normalled through the jack connector. This means that plugging in a jack overrides the
XLR source. Plug a microphone into the XLR socket leaving the jack unplugged. Plug a
line level source into the jack socket and select the front panel PAD switch. For line level
sources on XLR plug into the XLR leaving the jack unplugged and select PAD. This
feature lets you connect a wide 70dB range of mic or line sources on either XLR or jack.

Both XLR and jack inputs are 3 wire balanced. This prevents interference pickup on long
cable runs when connecting to balanced sources such as microphones. To connect an
unbalanced XLR source link Pin 3 to Pin 1 in the XLR plug. The jack input automatically
grounds the cold (-) input to accept unbalanced TS (mono) jack sources. To connect an
unbalanced source using a TRS (stereo) jack you should link ring to sleeve in the plug as
shown above. Do not select +48V phantom power when connecting unbalanced
sources.

MIC +48V Press this tamperproof underpanel switch when connecting to microphones
such as condenser types which require phantom power. This provides +48V DC to pins
2 and 3 of the XLR.

WARNING Do not connect unbalanced sources or cables to the XLR inputs

when phantom power is selected. Use +48V only with balanced microphones
which require powering. Note that harm will not be done to non powered
microphones as long as they are balanced. To avoid loud clicks always turn the
channel off by releasing the ON switch when switching +48V on or off and when
plugging or unplugging microphones.

INSERT You do not need to plug anything into the insert socket for normal operation. It

is a break point that lets you plug in an external signal processor such as a compressor
or noise gate if required. Plugging in a jack breaks the signal path after the input pre­amp and before the EQ. The signal is unbalanced and operates at a nominal 0dBu line
level. Use a TRS jack wired as shown above to connect the SEND to the processor input
and the RETURN from the processor output. The sleeve provides the common ground for
cable screening. Use a TRS Y-adapter and two standard jack leads or wire two leads to
a TRS plug. If required you can tap off the send to provide an alternative pre-EQ direct
output by plugging in a lead with tip and ring shorted together so that the channel signal
path is not interrupted.

DIR OUT This provides a post-fader direct output for connection to external processing
or recording equipment. This can be set to pre-fader by changing an internal link option.
The output operates at 0dBu and is impedance balanced on TRS jack to provide the
benefit of interference rejection when connecting to equipment with balanced inputs. You
can also connect to unbalanced equipment as shown above.

WZ20S User Guide 13

Connecting the Stereo Channel

19-20

A

IN

L

R

B

IN

M

L /

R

INPUT A This provides a pair of RCA phono sockets for connection to stereo sources
such as CD players, MiniDisc and record decks. The inputs are unbalanced and can
accept line levels signals from as low as –20dBu to a high +10dBu. The level is matched
to the console using the front panel GAIN A control. The signal can be mixed with Input
B if required by pressing both A and B ON switches together. An optional RIAA card may
be fitted internally for direct connection to a magnetic turntable cartridge. Refer to your
ALLEN & HEATH agent for details.

INPUT B This provides a pair of TRS jack sockets for connection to any line level
source. For stereo sources plug into both the L/M and R sockets. For mono sources
plug into just the L/M socket leaving the R socket unplugged. In this case the signal is
normalled through the R socket to the right channel. The inputs are balanced to provide
interference rejection when connecting to 3 wire balanced sources using long cables.
The socket automatically grounds the cold (-) input to accept unbalanced 2 wire TS jack
sources. To connect an unbalanced source using a TRS jack you should link ring to
sleeve in the plug as shown above. The inputs can accept line level signals from as low
as –20dBu to a high +10dBu. The level is matched to the console using the front panel
GAIN B control. The signal can be mixed with Input A if required by pressing both A and
B ON switches together.

Connecting the External Inputs

2

EXT I N

L

R

EXT IN 1 (2) This provides a pair of TRS jack sockets for connection to line level sources
such as effects, 2-track or monitor returns. A tamperproof front panel switch determines
whether the signal feeds MIX 1(2) or just the monitor select switch bank. For stereo
sources plug into both the L/M and R sockets. For mono sources plug into just the L
socket leaving the R socket unplugged. In this case the signal is normalled through the R
socket to the right channel. The inputs are balanced to provide interference rejection
when connecting to 3 wire balanced sources using long cables. The socket automatically
grounds the cold (-) input to accept unbalanced 2 wire TS jack sources. To connect an
unbalanced source using a TRS jack you should link ring to sleeve in the plug as shown
above. The operating level is –10dBV but may be set for +4dBu by changing an internal
link option.

14 WZ20S User Guide

Connecting Mix 1 and Mix 2 Outputs

OUT

2

MIX

L

R

MIX2

OUT

R

M

L

INSERT

R

MIX1

OUT

1

MIX

L

INSERT

R

LL

R

INSERT Both MIX1 and MIX2 provide insert points for left and right channels. You do
not need to plug anything into the insert socket for normal operation. It is a break point
that lets you plug in an external signal processor such as a limiter or equaliser if required.
Plugging in a jack breaks the signal path after the buss mix amp and before the master
fader. The signal is unbalanced and operates at a nominal –2dBu line level. Use a TRS
jack wired as shown above to connect the SEND to the processor input and the RETURN
from the processor output. The sleeve provides the common ground for cable screening.
Use a TRS Y-adapter and two standard jack leads or wire two leads to a TRS plug.

L R XLR OUTPUTS The MIX1 and MIX2 main left and right outputs are on differentially
balanced XLR connectors. 3 Pin female XLR plugs are required to connect these.
Connect to balanced equipment for maximum interference rejection on long cable runs.
To connect to unbalanced equipment link Pin 3 to Pin 1 in the XLR plug as shown.
Signal level is a nominal +4dBu (0 on the meters). Typical uses include feeds to
amplifier/speakers systems, stereo submix to main console, recording and broadcast.
MIX1 can provide a stereo group output when configured as a subgroup to MIX2 by
pressing a tamperproof front panel switch.

MONO OUTPUT This provides a sum of the post-fader MIX2 left and right signals. The
output is differentially balanced XLR operating at a nominal +4dBu. Connect to balanced
or unbalanced equipment as described above for the L R outputs. Typical uses include
feeding mono speaker, submix, centre fill, sub bass, mono zone, sound to light and
recording systems.

MIX2 L R TRS OUTPUTS Stereo MIX2 is available on a pair of 3 pole TRS jack sockets
in addition to the XLR outputs. These are impedance balanced to reduce noise pickup
on long cable runs. Connect to balanced or unbalanced equipment as shown above.
The signal is the same as the post-fader XLR output but operating 6dB lower at a
nominal –2dBu. Typical uses include feeding a stereo recorder, additional stereo zone,
or as an alternative to the XLR outputs.

WZ20S User Guide 15

Connecting Auxiliary Outputs

AUX6AUX AUXAUX5 4

23 AUX AUX 1

SENDS

AUX 1-6 OUTPUTS Each of the six auxiliary sends is available on a 3 pole TRS jack
socket. These are impedance balanced to reduce noise pickup on long cable runs.
Connect to balanced or unbalanced equipment as shown above. Nominal operating level
is –2dBu but gain is available using the send master control to drive +4dBu if required.
Use pre-fade auxes to feed stage monitor, foldback and cue systems. Use post-fade
auxes to feed effects processors such as reverb, and to provide independent zone,
cleanfeed and recording feeds.

Connecting the Headphones and Local Monitor

L

R

TIP = L
RING = R

2

LOCAL MONITOR OUTPUTS A pair of 3 pole TRS jack sockets provide left and right
outputs from the console local monitor system. These are impedance balanced and can
be connected to balanced or unbalanced equipment as shown above. Nominal operating
level is –2dBu but gain is available to drive +4dBu if required. Independent control is
provided for the local and the headphones monitor systems.

HEADPHONES 2 OUTPUT Two outputs are available for stereo headphones, one on
the front panel, the other on the rear panel. This is convenient for permanent installation
or when two headphones are required at the same time, for example presenter and guest
in a broadcast application. The same signal is available from both. Headphones are
available in many different styles, impedances and volume ratings. To get the best from
your system we recommend that you use high quality closed ear headphones in the
range 30 to 600 ohms. 8 Ohm headphones are not recommended.

WARNING Some headphones are more sensitive than others and can

produce higher output levels. To avoid damage to your hearing start with the
PHONES level control at minimum and turn up only as much as is needed to
maintain comfortable listening level. Do not drive headphones at high listening
levels for long periods of time.

16 WZ20S User Guide

User Connector Options

SYS-L INK OUT

(opti on) (user connecti ons)

SYS-L INK OUT

(opti on) (user connecti ons)

REMOTE

REMOTE

SYS-LINK OUTPUT The console is supplied with a blank plate fitted here. An optional
kit of parts is available to install a 25 pin D-connector and circuit card which provides all
console outputs on a single connector. This is convenient when connecting the WZ20S
as an expander to another console. For example, the WZ20S can be used as a compact
effects submixer linked to a larger FOH console. Use a standard 25 pin one-to-one
shielded cable to plug this output into any ALLEN & HEATH console fitted with SYS-LINK
input. SYS-LINK operates unbalanced at –2dBu and is not intended for long cable runs.
Note that SYS-LINK input is not available on the WZ20S. Contact your ALLEN & HEATH
agent for further details.

USER CONNECTOR The console is supplied with a blank plate fitted here. A 25 pin D­connector may be installed and custom wired to satisfy the particular requirements of the
application such as a broadcast or club system. For example, switched faders could be
fitted to the console and wired to this connector to provide remote fader start for control of
music and jingle players. An optional switched fader kit is available from ALLEN &
HEATH. The installation of this connector should be carried out only by qualified
personnel. Contact your agent for further details.

WZ20S User Guide 17

Mono Input Channel

PAD Affects both the XLR (if no TRS jack is plugged in) and the TRS jack

input to attenuate the input signal by 30dB. Press PAD when plugging in line
level sources, or when the signal is too high with the GAIN control turned down.

GAIN Adjusts the input sensitivity to match the connected source to the
console 0dB operating level. This provides a wide 70dB range with continuous
adjustment for signals from –60dBu to –20dBu with PAD switched off, and –
30dBu to +10dBu with PAD on. Use the PFL system to correctly set the gain
using the console meters.

100HZ FILTER Switches in the high pass filter to cut frequencies below 100Hz
with a slope of 12dB/octave. Use this to clean up vocals by reducing
microphone proximity popping and low frequency ambient pickup, and to filter

GAI N

PAD

- 10

HF

12kHz

700

MF1

-15

1k

500Hz

PAD

-30dB

40

30

50

20

3kHz

3060

100Hz

0

+15

5k

7k

15kHz

0

out hum and rumble. The filter is post-insert and pre-EQ so that it affects the
signal returned from any inserted equipment by removing the unwanted low
frequencies before equalisation.

EQUALISER The channel equaliser is a powerful tool to creatively tailor the

sound within the mix, or to deal with source problems such as poor microphone
characteristics, noise and feedback. Start with the EQ controls set to their mid
(flat) position and make sure you have chosen the best type and position of
microphone for the source. Then adjust the EQ to achieve the sound you want.
Take time to experiment with the controls so you get to learn the effect the
equaliser can have on the sound.

The WZ20S mono channel provides separate tone control over four frequency
bands including two swept frequency (parametric) mids. The frequencies in
each band may be boosted or cut by up to 15dB. The centre flat position is
detented for quick resetting.

MF2

LF

60Hz

45

-15

60

35Hz

-15

-15

180Hz

0

0

EQ
IN

+15

1kHz

+15

+15

300

450

HF Turn this control clockwise to boost and anticlockwise to cut the high
(treble) frequencies. This has a shelving response with all frequencies above
the 12kHz turning point affected. Note that frequencies below 12kHz are
affected by a decreasing amount. Use HF boost to brighten up the sound by
adding sparkle, and cut to reduce source hiss or ambient high frequency mic
pickup.

MF1 Turn the +/- control clockwise to boost and anticlockwise to cut the higher
mid frequencies. This has a bell shaped peak/dip response that has maximum
boost or cut at the selected frequency. Use the upper control to select this
centre frequency between 500Hz and 15kHz. Boosting around 3kHz can
enhance the intelligibility of vocals helping them to cut through the mix. Cutting
to notch out a ringing frequency can help to increase the gain before feedback.

MF2 This is similar to MF1 but affects the lower mid frequencies selectable
from 35Hz to 1kHz. Boosting can enhance the warmth of the sound while
cutting can reduce the effect of resonant or boomy frequencies.

LF Turn this control clockwise to boost and anticlockwise to cut the low (bass)
frequencies. This has a shelving response with all frequencies below the 60Hz
turning point affected. Note that frequencies above 60Hz are affected but by a
decreasing amount. Use LF boost to enhance low end punch, and cut to further
reduce source hum and rumble.

EQ IN Switches the equaliser in or out of the signal path. Use this to check
the effect of the control settings by comparing the equalised and unequalised

.

signals

18 WZ20S User Guide

MIX1

MIX2

GAI N

PAD

HF

12kHz

MF1

MF2

LF

60Hz

AUX

AUX

AUX

AUX

AUX

AUX

PAN

PFL

AUXILIARY SENDS These controls route the channel signal to the AUX 1

PAD

-30dB

40

30

50

20

- 10

3060

100Hz

0

-15

+15

3kHz

5k

1k

700

7k

500Hz

15kHz

0

-15

+15

180Hz

300

60

45

450

35Hz

1kHz

0

-15

+15

0

-15

+15

EQ
IN

1

0

OO

+6

2

0

+6

OO

3

0

+6

OO

4

0

OO

+6

POST

PRE

5

0

OO

+6

6

0

OO

+6

POST

PRE

L

R

ON

PEAK

!

10

5

0

10

20

30

OO

to 6 mix. These are independent from the main mix and can therefore provide
additional outputs for monitors, effects, zone, recording feeds and so on.

AUX LEVEL

Adjusts the level of the channel signal in each mix. Turn fully

anticlockwise to turn the signal off, fully clockwise for a maximum +6dB boost.
The normal ‘0’ position is marked. Each of the 6 aux mixes has its own
dedicated channel level control.

PRE/POST With the switch in the up position the post-fader channel signal is
routed to the mix. Press the switch to select the pre-fader signal instead. One
switch affects AUX 1-4, another AUX 5-6.

Set the switch to POST to send to external effects devices such as reverb
processors. The amount of signal sent to the device follows the fader level.
The processed (wet) signal returned to the mix elsewhere is therefore in
proportion to the direct (dry) routed signal regardless of fader position. Post­fade sends are also used to provide zone or recording feeds where the outputs
should follow the fader movements.

Set the switch to PRE to send to monitors such as stage or remote foldback or
recording cue. The amount of signal in the monitor mix is independent of the
fader movements. therefore adjustments made to the main mix will not affect
the balance of the monitors. Note that selected channels in a monitor mix can
still be set post-fader if required, for example to prevent ‘dressing room’ talk
when working with radio microphones. The pre-fade sends are set post-EQ
post-ON as standard. These can be reconfigured pre-EQ and/or pre-ON by
resoldering internal links.

PAN Positions the channel signal between left and right in the stereo mix to
create the required image. The centre (mono) position is detented for quick
resetting.

ON Turns the channel signal on or off. The green LED lights when the
channel is turned on. All outputs except the insert send and PFL are muted
when the channel is turned off. Note that the pre-fade aux sends can be
internally reconfigured so that they are not affected by this switch if required.

PEAK The red LED lights when the channel is within 5dB of clipping. This
warns that you should turn back the GAIN control to reduce the signal level.

PFL Press PFL to listen to the pre-fader channel signal using the headphones
or local monitor. This does not affect the main outputs and lets you audition the
signal before you raise the fader and introduce it into the mix. The signal level
is also displayed on the console monitor meters so that GAIN can be set to
achieve the correct operating levels. The PEAK LED half lights to show which
channel PFL has been selected.

MIX 1 (2) Routes the post-PAN channel signal to MIX1 and MIX2. None, one
or both may be selected.

FADER A 100mm long throw fader adjusts the level of the channel signal and
provides a clear visual indication of its contribution to the mix. It does not affect
the pre-fader AUX sends. It does affect DIR OUT unless it has been
reconfigured pre-fader. The ‘0’ mark indicates normal operating position. The
fader can be set above or below this depending on the balance required in the
mix. A further 10dB of boost is available at the top of its travel. Use the PFL
system to check that the channel gain is correctly set before raising the fader to
add the channel to the mix.

WZ20S User Guide 19

Stereo Input channel

GAI N

GAI N

HF

12kHz

MF1

MF2

LF

60Hz

DUAL INPUTS A and B

The stereo channel features two stereo inputs
with independent gain control and on/off switching. One source may be
selected at a time, or both may be mixed together further increasing the number
of simultaneous inputs to the mix. This means that you can leave two stereo
sources permanently connected to the console without the need to repatch or
readjust the gain settings.

5

0

-5

-10

0

-5

-10

-15

-15

-15

10

15

20

ON

5

10

15

20

ON

MONO

0

+15

0

+15

0

+15

0

GAIN A (B) Adjusts the channel input sensitivity to match the connected
source to the console 0dB operating level. This provides a 30dB range with
continuous adjustment for signals from –20dBu to +10dBu. Use the PFL
system to correctly set the gain using the console meters.

ON A (B) Switches stereo source A (RCA phono input) and/or stereo source B
(TRS jack input) on and routes it to the channel.

MONO Combines left and right to provide a mono signal from a stereo source,
or to feed a mono source to both channels.

EQUALISER The channel equaliser is a powerful tool to creatively tailor the

sound within the mix, or to deal with problems such as poor source
characteristics, noise and feedback. Start with the EQ controls set to their mid
(flat) position. Then adjust the EQ to achieve the sound you want. Take time to
experiment with the controls so you get to learn the effect the equaliser can
have on the sound.

The WZ20S stereo channel provides separate tone control over four fixed
frequency bands. The frequencies in each band may be boosted or cut by up
to 15dB. The centre flat position is detented for quick resetting.

HF Turn this control clockwise to boost and anticlockwise to cut the high
(treble) frequencies. This has a shelving response with all frequencies above
the 12kHz turning point affected. Note that frequencies below 12kHz are
affected by a decreasing amount. Use HF boost to brighten up the sound by
adding sparkle to compensate for poor source material, or cut to reduce source
hiss or high frequency noise.

MF1 Turn the +/- control clockwise to boost and anticlockwise to cut the higher
mid frequencies. This has a bell shaped peak/dip response that has maximum
boost or cut at 2.5kHz. Boost to add presence, or cut to reduce harshness.

-15

+15

EQ
IN

MF2 This is similar to MF1 but affects the lower mid frequencies centred on
250Hz. Boosting can enhance the warmth of the sound while cutting can clean
up a boomy sound.

LF Turn this control clockwise to boost and anticlockwise to cut the low (bass)
frequencies. This has a shelving response with all frequencies below the 60Hz
turning point affected. Note that frequencies above 60Hz are affected but by a
decreasing amount. Use LF boost to enhance low end punch, and cut to
reduce source hum and rumble.

EQ IN Switches the equaliser in or out of the signal path. Use this to check
the effect of the control settings by comparing the equalised and unequalised

.

signals

20 WZ20S User Guide

MIX1

MIX2

GAI N

GAI N

HF

12kHz

MF1

MF2

LF

60Hz

AUX

AUX

AUX

AUX

AUX

AUX

BAL

PFL

DUAL
STEREO

5

0

10

-5
15

20

-10

ON

5

0

10

-5
15

20

-10

ON

AUXILIARY SENDS

to 6 mix. These are independent from the main mix and can therefore provide
additional outputs for monitors, effects, zone, recording feeds and so on.

AUX LEVEL

anticlockwise to turn the signal off, fully clockwise for a maximum +6dB boost.
The normal ‘0’ position is marked. Each of the 6 aux mixes has its own
dedicated channel level control. The stereo left and right signals are mixed
together to produce a mono sum that feeds the aux mix. This may be changed

Adjusts the level of the channel signal in each mix. Turn fully

These controls route the channel signal to the AUX 1

by resoldering internal links so that all pre and/or post-fader sends are

MONO

0

-15

+15

0

-15

+15

0

-15

+15

0

+15

-15

EQ
IN

1

0

OO

+6

2

0

OO

+6

3

0

OO

+6

4

0

OO

+6

POST

PRE

5

0

OO

+6

6

0

OO

+6

POST

PRE

configured in stereo with left signal feeding odd numbered auxes and right
feeding even.

PRE/POST With the switch in the up position the post-fader channel signal is
routed to the mix. Press the switch to select the pre-fader signal instead. One
switch affects AUX 1-4, another AUX 5-6.

Set the switch to POST to send to external effects devices such as reverb
processors. The amount of signal sent to the device follows the fader level.
The processed (wet) signal returned to the mix elsewhere is therefore in
proportion to the direct (dry) routed signal regardless of fader position. Post­fade sends are also used to provide zone or recording feeds where the outputs
should follow the fader movements.

Set the switch to PRE to send to monitors such as stage or remote foldback or
recording cue. The amount of signal in the monitor mix is independent of the
fader movements. therefore adjustments made to the main mix will not affect
the balance of the monitors. Note that selected channels in a monitor mix can
still be set post-fader if required, for example to prevent ‘dressing room’ talk
when working with radio microphones. The pre-fade sends are set post-EQ
post-ON as standard. These can be reconfigured pre-ON by changing internal
links.

BAL Adjusts the relative left and right levels in the stereo mix to create the
required balance. This becomes a PAN control if the channel is operated in
mono. The centre position is detented for quick resetting.

ON Turns the channel signal on or off. The green LED lights when the
channel is turned on. All outputs except the PFL are muted when the channel

L

R

ON

PEAK

!

10

5

0

is turned off. Note that the pre-fade aux sends can be internally reconfigured so
that they are not affected by this switch if required.

PEAK The red LED lights when the channel is within 5dB of clipping. This
warns that you should turn back the GAIN control to reduce the signal level.

PFL Press PFL to listen to the pre-fader channel signal (in mono) using the
headphones or local monitor. This does not affect the main outputs and lets
you audition the signal before you raise the fader and introduce it into the mix.
The signal level is also displayed on the console monitor meters so that GAIN

5

10

can be set to achieve the correct operating levels. The PEAK LED half lights to
show which channel PFL has been selected.

MIX 1 (2) Routes the post-BAL channel signal to MIX1 and MIX2. None, one

20

or both may be selected.

FADER A 100mm long throw fader adjusts the level of the channel signal and

30

O

O

provides a clear visual indication of its contribution to the mix. It does not affect
the pre-fader AUX sends. The ‘0’ mark indicates normal operating position. A
further 10dB of boost is available at the top of its travel.

WZ20S User Guide 21

Master Section

POWER ON

1

POWER ON Green LED lights when the console is powered.

MIX1

MIX2

EXT1
IN

AUX

AUX

AUX

AUX

AUX

AUX

O

O

1

O

O

2

O

O

3

O

O

4

O

O

5

O

O

6

OO

EXT2
IN

0

+6

+16

+9

+6

+3

0

-6

-9 -9

-16

-20

-30

RL

MIX1

3

2

1

0

+4

1

1-2

0

2

+4

3

0

3-4

+4

4

0

5

5-6

+4

6

0

+4

0

+4

SPLIT
PFL

3

2

MONO

1

MIX2

MIX2MIX1

10

5

00

5

10 10

20

30 30

10

20

OO

PFL

MONITOR

PFL

4

4

0

5

5

MIX2

+6

PRG

+16

+9

+6

+3

0

-3-3

-6

-12-12

-16

-20

-30

R

L

5

6

010

AUX1

AUX2

AUX3

AUX4

AUX5

AUX6

EXT1

EXT2

MIX1

PFL ENABLE

5

6

0

1

DIM

0

7

8

9

7

8

9

SPLIT PFL

LEV

ALL UP =

MIX2

LOCAL
MONITOR

HEADPHONES 1 OUTPUT Two outputs are available for stereo
headphones, one on the front panel, the other on the rear panel. This
is convenient when two headphones are required at the same time,
for example presenter and guest in a broadcast application. The
same signal is available from both. Headphones are available in
many different styles, impedances and volume ratings. To get the
best from your system we recommend that you use high quality
closed ear headphones in the range 30 to 600 ohms. 8 Ohm
headphones are not recommended.

WARNING Some headphones are more sensitive than

others and can produce higher output levels. To avoid damage
to your hearing start with the PHONES level control at minimum
and turn up only as much as is needed to maintain comfortable
listening level. Do not drive headphones at high listening levels
for long periods of time.

EXTERNAL INPUTS Two external inputs are provided in

addition to the mono and stereo channels. Each has a pair of TRS
jacks to accept a line level stereo source. For mono sources plug into
the L jack only leaving the R jack unplugged.

MIX1(2) ROUTING SWITCHES These underpanel tamperproof
switches determine how the external inputs are to be used. There are
two main applications:

Mix Inputs To connect additional stereo or mono sources to either
or both MIX1 and MIX2. For example, you could use these to return
the processed output from effects devices such as reverb, to accept
an input from a submixer, or for 2-track replay into the mix. EXT1 can
route to either or both MIX1 and MIX2. EXT2 can route to MIX2 only.
This would give you a dedicated effects return to each mix, or one
return routed to both. The pre-level signal feeds the monitor source
selector. Use a pointed object such as a pen to select MIX1 and/or
MIX2 routing switches as required.

Monitor Inputs To return sources to the monitor selector for
monitoring only. With both switches in the up position the signal feeds
the monitor source selector and is not affected by the level control.
This is the case when the input is used for monitoring only and should
not feed the main mix, for example checking a stereo recording or an
off-air broadcast signal. The tamperproof underpanel routing switches
prevent accidental operation. If the switch were accidentally pressed
the signal would route back on itself and cause feedback. Decide the
application of these inputs and set the switches accordingly.

EXT1(2) IN The rotary controls adjust the level of the external inputs
when routed to MIX1 or MIX2 or both as selected on the routing
switches above. Note that these do not affect the feeds to the monitor
selector. Operating level is –10dBV as standard but may be changed
to +4dBu by resoldering an internal link.

OO

OO

22 WZ20S User Guide

POWER ON

MIX1

MIX2

EXT1
IN

O

+6

O

+16

+9

+6

+3

0

-6

-9 -9

-16

-20

-30

RL

MIX1

AUX

1

O

O

+4

AUX

2

O

O

+4

AUX

3

O

O

+4

AUX

4

O

O

+4

AUX

5

O

O

+4

AUX

6

OO

+4

SPLIT
PFL

MONO

MIX2

10

5

00

5

10 10

20

AUXILIARY MASTERS These provide six independent mix

1

MIX2

EXT2
IN

0

0

0

0

0

0

0

0

+6

OO

PRG

PFL

SPLIT PFL

+16

+9

+6

+3

0

-3-3

-6

-12-12

-16

-20

-30

R

L

MONITOR

PFL

5

6

4

LEV

3

7

2

8

1

9

010

AUX1

1

1-2

AUX2

2

AUX3

3

3-4

AUX4

4

AUX5

5

5-6

AUX6

6

EXT1

EXT2

ALL UP =

MIX2

MIX1

PFL ENABLE

5

6

4

LOCAL

7

3

MONITOR

2

8

1

9

0

0

1

DIM

MIX2MIX1

10

5

5

20

outputs which can be used to provide foldback, cleanfeed and cue
monitors, effects and recording sends, zone feeds and any other
special mixes required.

AUX 1-6 Adjust the output level of each auxiliary mix. Turning the
control clockwise adjusts from fully off to +4dB boost. The normal ‘0’
position is marked.

MIX1 AND MIX2 MASTERS These are the main console

outputs. You can route each input channel to either or both outputs.
You can route MIX to create a stereo subgroup to MIX2 main output.
Both outputs provide master fader control, inserts, metering and
balanced XLR outputs. MIX2 provides additional TRS jacks and an
XLR mono output. This provides the flexibility to satisfy most audio
system applications. Refer to the section on applications later in this
User Guide.

MIX1 METERS A pair of meter bars display the post-fader left and
right output levels of stereo MIX1. Each meter has 12 LEDs to
indicate signal levels from as low as –30dB. Green and yellow LEDs
indicate normal operating levels. The top red LED lights at +16dB to
warn that you are within 5dB of clipping. Meter ‘0’ represents +4dBu
at the main outputs. The meters are peak responding. This means
that they have a fast attack and are able to display fast transients
accurately. With the output faders at their ‘0’ mark you should adjust
the mix so that the signal averages ‘0’ on the meters with highest
peaks no more than ‘+6’. This still leaves plenty of mix headroom.

MONITOR / MIX2 METERS A pair of meter bars displays the level of
the selected monitor source or PFL. With all selector switches up
these default to display the post-fader left and right output levels of
stereo MIX2.

MIX1 to MIX2 Routes the post-fader MIX1 signal to MIX2 to create a
stereo subgroup. Route all the channels you want to group to MIX1
only. Route the other channels to MIX2 only. Press the underpanel
MIX2 switch above the master fader to route MIX1 to MIX2. This is a
tamperproof switch to avoid accidental operation in situations where
MIX1 and 2 are used as independent outputs. It should be selected
using a pen or similar pointed object. MIX1 becomes a subgroup
giving you single fader control over all routed levels. You can also
insert a signal processor such as a compressor to affect all signals in
the group. MIX2 becomes the main output.

MASTER FADERS MIX1 and MIX2 each have a 100mm long throw
fader to adjust the output level. This is a stereo fader which adjusts
the left and right signals at the same time. The ‘0’ mark indicates
normal operating position. The fader can be set above or below this
depending on the output level required. A further 10dB of boost is
available at the top of its travel. However, if you find yourself normally
setting the fader in the lower half of its travel then the connected
equipment may be too sensitive for the operating level of the console.
With the fader set to its ‘0’ position adjust the input level trim of the
connected equipment accordingly.

30 30

OO

OO

The MIX1 and MIX2 insert points are pre-fader. The level of any
inserted processing equipment will be affected by the master faders.
The inserted equipment should be set to match the –2dBu operating
level of the console.

WZ20S User Guide 23

1-2

3-4

5-6

PFL

3

2

1

1

2

3

4

5

6

+16

+9

+6

+3

0

-3

-6

-9

-12

-16

-20

-30

R

L

MONITOR

PFL

5

4

AUX1

AUX2

AUX3

AUX4

AUX5

AUX6

EXT1

EXT2

MIX1

6

PRG

010

7

8

9

SPLI T PFL

LEV

ALL UP =

MIX2

CONSOLE MONITOR SYSTEM The WZ20S provides

extensive console monitoring facilities to satisfy a wide range of
applications including broadcast and club mixing. Every signal can be
monitored individually or within any mix. Two systems are provided,
headphones and local monitor. Two sets of headphones may be
connected at the same time. The local monitor can be used to feed a
stereo booth, stage or studio speaker system. The PFL (Pre Fade
Listen) system lets you quickly check channel signals and correctly
set gain.

MONITOR / MIX2 METERS A pair of meter bars displays the level of
the selected monitor source or PFL. With all selector switches up
these default to display the post-fader left and right output levels of
stereo MIX2. When SPLIT PFL is selected the left meter displays the
active PFL signal, the right displays the switch bank source in mono.

Each meter has 12 LEDs to indicate signal levels from as low as –
30dB. Green and yellow LEDs indicate normal operating levels. The
top red LED lights at +16dB to warn that you are within 5dB of
clipping. Meter ‘0’ represents +4dBu at the XLR outputs. The meters
are peak responding. This means that they have a fast attack and are
able to display fast transients accurately.

PFL A large red LED lights when a channel PFL is selected. This
indicates that the selected channel PFL signal is heard in the
headphones and displayed on the monitor meters. PFL also
overrides the local monitor if PFL ENABLE has been selected.

It is important to use PFL to set the channel gains correctly to
maintain the wide dynamic range achievable with this console. If set
too high then the signal may clip resulting in a harsh distorted sound.
If set too low then the signal-to-noise ratio is reduced and residual
hiss may be heard. You should adjust the channel gain so that the
signal averages ‘0’ on the monitor meters with highest peaks no more
than ‘+6’.

HEADPHONES LEVEL Adjusts the level of the signal in the stereo
headphones. This does not affect the level of the local monitor. Heed
the warning printed on the previous page regarding loud listening
levels.

MONITOR SOURCE SELECTOR A 9 way switch bank is used to
select which signal is heard in the headphones, local monitor and
displayed on the meters. This defaults to post-fader MIX2 signal with
all switches up. Press the required switch to monitor MIX1, AUX1 to 6,
or EXT IN 1(2). PFL automatically overrides the selected source.
Press a related pair of Aux switches to monitor them in stereo, for
example AUX5 on left, AUX6 on right. Press a single AUX switch to
check it in mono.

Switch priority is PFL overrides AUX1/2 overrides AUX3/4 overrides
AUX5/6 overrides EXT1 overrides EXT2 overrides MIX1 overrides
MIX2. For example you can select MIX1 as your source, then press
EXT1 to check a recording level without having to first deselect MIX1.

24 WZ20S User Guide

POWER ON

MIX1

MIX2

EXT1
IN

AUX

AUX

AUX

AUX

AUX

AUX

O

O

1

O

O

2

O

O

3

O

O

4

O

O

5

O

O

6

OO

EXT2
IN

0

+6

+16

+9

+6

+3

0

-6

-9 -9

-16

-20

-30

RL

MIX1

3

2

1

0

+4

1

1-2

0

2

+4

3

0

3-4

+4

4

0

5

5-6

+4

6

0

+4

0

+4

SPLIT
PFL

3

2

MONO

1

MIX2

MIX2MIX1

10

5

00

5

10 10

20

30 30

10

20

OO

PFL

MONITOR

PFL

4

4

0

5

5

MIX2

+6

PRG

+16

+9

+6

+3

0

-3-3

-6

-12-12

-16

-20

-30

R

L

5

6

010

AUX1

AUX2

AUX3

AUX4

AUX5

AUX6

EXT1

EXT2

MIX1

PFL ENABLE

5

6

0

1

DIM

0

7

8

9

7

8

9

1

SPLIT PFL

LEV

ALL UP =

MIX2

LOCAL
MONITOR

LOCAL MONITOR LEVEL Adjusts the level of the signal to the
stereo local monitor output jacks. This does not affect the level in the
headphones.

PFL ENABLE With this underpanel switch in its down position PFL
automatically overrides the selected source in the local monitor
output. The switch is tamperproof to prevent accidental operation. In
the up position PFL affects the headphones but not the local monitor.
This lets the engineer or presenter cue channels using PFL in the
headphones only. This is typical in broadcast or club monitoring. In
broadcast, the local monitor could also be used to feed guest
speakers or headphones. Here, PFL should be disabled so that only
the presenter is able to cue the channels. In club mixing the local
monitor may feed a booth speaker system. The DJ may prefer to cue
using headphones only.

DIM Press this switch to mute the local monitor output. An internal
option reconfigures this to attenuate the signal by 20dB rather than
mute it if required, for example to keep some program audible at all
times. The red LED lights when the monitor is dimmed. This function
can be remote controlled by options wired internally. For example, in
a broadcast application a switched fader could be fitted and wired to
mute the studio monitor speakers when the presenter mic is live.
Refer this work to competent service or installation personnel. Further
information is available in the applications section of this User Guide.

SPLIT PFL Press this switch to change the way PFL operates.
Normally, pressing a channel PFL switch overrides both left and right
monitor program signals with the mono PFL signal. With the switch
pressed, PFL overrides just the left channel. The left program signal
sums with the right so that the program remains in the right channel
but in mono. The left monitor meter displays the PFL signal, right
displays program. This is important in applications such as broadcast
or club mixing where the main program should remain audible while
cueing other channels ready to bring them into the mix. It is most
effective when using headphones.

MONO Sums the left and right monitor signals together so that the
selected stereo source can be checked in mono. Use this to check for
mono compatibility and phase problems, especially important in
broadcast and recording applications. A drop in level or loss of low
frequencies when pressed indicates reversed phase between the left
and right signals.

OO

OO

WZ20S User Guide 25

Application Notes

The WZ20S is well suited to many high performance live, recording and installed sound
applications including multi source stereo mixing, dual output submixing, club systems,
low end broadcast, production mixing… and more. The following notes present
suggestions for these applications. Of course, you may find different or better ways to
suit the particular requirements of your application.

Mixing Many Stereo Sources

There are many situations where you need to mix multiple stereo sources for
example keyboards, MIDI synthesisers, voice modules, sound cards, samplers,
outboard mic preamps, effects processors, CD, vinyl, DAT, MiniDisc, new
media players and recorders, stereo recorded tracks.

Dual stereo inputs You can connect two stereo sources to each channel and
switch between them or mix them together as required. Inputs A and B have
independent gain control so that the balance can be set as required. You do
not need to reset the gain each time you switch the inputs. You also have the
convenience of selecting either the RCA phono or TRS jack connections as
appropriate rather than using cable adapters.

External stereo inputs The two additional EXT inputs increase the number of
stereo inputs to 18. You still have the four mono channels for microphone or
line level inputs. The EXT inputs are best used to return the processed signal
from effects devices such as reverb, or to plug in a submixer. Remember to
select the MIX1(2) routing switches.

Signal processing All channels provide 4 band EQ for creative or corrective
equalisation. The six AUX sends provide plenty of outputs for effects, monitors
and special feeds. The effects can be returned to the EXT or dual stereo
channels. For example, two stereo reverbs could be combined on one stereo
channel. The mono channels and main outputs provide inserts for patching in
additional signal processors such as compressors.

Production and Recording

The number of inputs and processing power together with the sonic purity of
analog sound make the WZ20S well suited to professional recording and
program production.

Inputs Connect up to 4 microphones and 16 stereo line sources plus 2 effects
returns. Up to 6 stereo channel A inputs can be optionally fitted with the
internal RIAA card for direct connection to record decks. For multitrack
recording you can connect up to 16 track returns to the 8 stereo channels. You
can use either mono or stereo channels to connect to outboard mic preamps,
increasingly common in the studio.

Outputs The two stereo outputs can feed independent recording devices.
This is useful when recording translations and voiceovers. Use the MIX2 jack
outputs when connecting to low level devices. Set the EXT1(2) routing
switches to their up position when returning the 2-track outputs to the monitor
select bank.

Subgrouping Select MIX1 to MIX2 to create a stereo subgroup for single
fader control and inserted processing. In this case use MIX2 as the main
output.

26 WZ20S User Guide

Dual Output Submixing

The WZ20S provides a versatile 4 mono, 8 dual stereo format for submixing a
wide variety of sources. Typical applications include on-stage stereo keyboard
mixing, and submixing effects returns to the main FOH console.

Balanced inputs Use the stereo B input TRS jacks when connecting to long
stage cable runs. This reduces interference pickup. Select +48V for any
microphones that require phantom power.

Dual stereo outputs MIX1 and MIX2 let you create two independent stereo
mixes to feed the main console. For example, you could provide two stereo
keyboard mixes for more flexible FOH mixing. Alternatively, you could use the
WZ20S for two independent submixing tasks. Use the MIX2 mono output if a
dedicated or simultaneous mono feed is required. All the main outputs are
available on balanced XLR to directly feed a professional multicore to console
system. They both provide full metering and insert points for signal processing.

Monitoring Apart from headphones, the local monitor can be configured to
provide stereo or mono stage monitoring either as wedge speakers or IEM (In
Ear Monitor). This offers PFL override and the ability to mute the output without
upsetting the adjusted level.

Effects submixing Fitting the optional SYS-LINK output expander card
provides a single cable connection to the main console. All the MIX and AUX
outputs as well as the PFL system are linked to the related circuits when
connecting to another ALLEN & HEATH console fitted with SYS-LINK.

Mounting convenience Rotate and fix the connector pod as required for
flightcase, desktop or rack mounting. It is usual to install the effects or stage
submixer in a rack system together with the processing equipment.

Professional suitability The WZ20S is built to the same high standard as top
end consoles used in major live sound applications. Its all steel construction,
together with individual circuit cards, make it ideal as a professional sidecar to
the FOH console. A high grade fader option is available as an option. The
universal mains power input allows connection to most world wide voltages.

Outside Broadcast

The WZ20S provides a compact rack mountable solution for remote broadcast
telecast or recording.

Inputs Up to 4 announcer or ambient microphones can be directly connected
with individual phantom power selection. The input stage provides a very wide
dynamic range, particularly important during sports commentating. Use the
stereo inputs for camera, tape or effect sources, mix minus or host feeds, inputs
from submixers, stereo microphone preamps and so on.

Outputs MIX1 and MIX2 can provide independent broadcast feeds, for
example an ‘effect’ only (ambient pick up) and ‘effect + announcer’ feeds. This
is useful where the ambient sound is recorded for later voiceover dubbing, such
as news report preparation. Full metering is provided on both outputs.
Additional pre/post outputs are available from the 6 AUX sends.

Monitoring In addition to the headphones, use the local monitor output to feed
the location booth speakers. All sources can be independently checked and
metered. Use the EXT inputs for two dedicated monitor returns such as off-air
and recording returns.

WZ20S User Guide 27

Broadcast Installation

The WZ20S provides an affordable yet professional broadcast console for
community, hospital and other small radio stations. It offers broadcast specific
features without the huge cost of dedicated broadcast consoles.

Mono Inputs Plug in the presenter and guest microphones. These can also
be used as telephone channels fed from suitable hybrid units. Select the PAD
switch for any line level sources.

Stereo inputs The 8 channels provide plenty of inputs for sources such as
CD, record players, jingle playback, media players, outside broadcast and so
on. The RIAA card can be fitted for direct connection to record turntables.

External monitor sources Use the EXT inputs as additional monitor sources
such as off-air and recording returns. Make sure that the tamperproof routing
switches are in their up position. This lets you select the source for monitoring
but prevents it routing back into the mix.

Stereo outputs MIX1 typically provides the stereo broadcast feed. MIX2 can
provide a second independent stereo feed. Both have dedicated metering,
inserts for processors such as limiters or EQ, and balanced XLR connections.
The additional MIX2 TRS jacks can be connected to a 2-track machine for
broadcast or production recording. This is ideal if you use the same console for
both the preparation and broadcast of the program.

Mono output Alternatively, use MIX2 as a dedicated mono feed, for example
simultaneous stereo and mono broadcast or recording. If an independent mono
mix is not required, the mono output can follow the stereo output by selecting
the tamperproof subgroup switch above the MIX1 fader and deselecting all
channel MIX2 routing switches.

Aux sends The 6 AUX sends provide ample additional feeds. Set pre-fade for
cue sends, and post-fade for sends to effects processors such as reverb and
echo. The processed (wet) reverb signal can be returned to the mix through a
stereo channel. The dual inputs allow two units to be returned through one
stereo channel, providing single fader control of two effects.

Cleanfeed Otherwise known as ‘mix minus’ this is a cue feed sent to the
telephone caller or outside broadcast unit. Use an AUX mix with channels set
post-fade. Set all the send levels except the caller channel to the ‘0’ position.
Make sure the caller channel is turned off. This prevents the callers own voice
returning to the telephone and causing feedback. You could press the PRE
switch so that the caller can be spoken to and prepared before the presenter
goes on-air.

Monitoring Two headphone outputs are provided to feed both the presenter
and guest. Alternatively, feed the guest system from the local monitor output
with PFL disabled to allow presenter only cueing. Headphones and local
monitor have independent level control. The local monitor could be used to
drive a studio speaker system. Press DIM to mute (or alternatively attenuate)
the speakers, important when the presenter is on-air. Any signal can be
monitored by selecting one of the nine source selectors or a channel PFL. Use
SPLIT PFL to cue a source while keeping an ear on the broadcast program.
Check mono compatibility of the broadcast signal by pressing MONO.

Customisation There is a host of internal options which can be fitted or
reconfigured to meet the exact requirements of a particular installation. These
include fitting switched faders for remote start of jingle, music players, and on­air lamps, and automatic muting of the local monitor, for example wired to the
presenter mic channel fader, ON or PFL switches. A 25 pin REMOTE user
connector can be fitted and custom wired as required. Note that all internal
WZ20S reconfiguration and fitting of options should be referred to competent
technical personnel only.

28 WZ20S User Guide

Club Installation

The WZ20S versatility and number of source inputs makes it ideal as a high
performance installed club console.

Hybrid application The console provides facilities for dance/DJ and
live/cabaret mixing. As a ‘house’ mixer it would be expected to alternate
between performance DJ’ing, house DJ, live acts, cabaret, karaoke and
background music.

Dance/DJ Plug the music sources such as CD and record decks into the
stereo channels. An RIAA preamp option can be installed for direct connection
to record decks. Typically, the guest DJ would plug his favourite mixing ‘box’
into a stereo channel. There are enough stereo inputs to leave all sources
permanently connected. A DJ microphone may be plugged into a mono
channel.

Live/cabaret The mono channels provide facility for mixing up to 4
microphones for live acts such as musical duos and cabaret. Many acts use
backing tracks such as CD or MiniDisc. These should be plugged into stereo
channels. Use pre-fade AUX sends to feed foldback monitors such as stage
wedge speakers. Use post-fade auxes to feed effects processors such as
reverb, typically applied to vocals or guitar. The wet reverb effect can be added
to the mix by returning it to an available stereo channel or an EXT input. Make
sure the correct EXT routing switches are selected.

Grouping You can create a ‘live’ group by assigning MIX1 as a stereo
subgroup to MIX2. Here, the live act microphone, backing tracks and effects
returns should be routed to MIX1 only. The ‘DJ’ sources should route direct to
MIX2 only. This lets you control the live mix with a single fader, for example to
turn the live sources off when the DJ is performing.

Output example 1 MIX2 feeds the house system with its MONO output
driving the sub bass or additional zone speakers. Use the additional TRS jack
outputs to drive a sound-to-light controller or for recording the show. MIX1
provides a ‘live’ subgroup as described above. Select the underpanel switch
above the fader. Alternatively, MIX1 could feed an independent stereo zone.
This could be assigned for music mix only, leaving the DJ and MC microphones
active in the main performance or dance floor area only.

Output example 2 Here, MIX1 feeds the house system. MIX2 is assigned to
provide a music only zone feed. This could be the DJ booth speaker system or
independent music only zone. The additional TRS jacks can be used for
recording music only. The MONO output could feed a sound-to-light controller
not affected by the DJ or other microphones. Post-fade auxes can be used to
feed independent mono zones. The main outputs have independent meters,
balanced XLR connections and inserts for plugging in processors such as
limiters and EQ.

Monitoring Independent headphones and local monitor outputs satisfy the
specific needs of club mixing. Use SPLIT PFL to cue the next source in one ear
while keeping the program in the other with relative levels displayed on the
meters. This is ideal when matching music styles or beat. The local output
feeds the booth monitor speakers. Disable PFL if you want headphones only
cueing. The booth speakers can be muted (or optionally attenuated) by
pressing the DIM switch. Alternatively, use the MIX2 output to feed the booth
speakers if music only is required.

WZ20S User Guide 29

Options

The WZ20S is designed to offer the utmost flexibility to satisfy your application without
modification. However, the following internal options are provided to allow customisation
to satisfy the more specialist applications. This work requires access to the internal
assemblies and resoldering of circuit card links and should be carried out by competent
technical personnel only. Further information and details are printed in the WZ20S
Service Manual, available from your service agent, or by contacting ALLEN & HEATH
technical support.

Internal Configuration Link Options

Mono channel AUX options The pre-fade sends are set post-EQ, post-ON

as standard. Links on the mono circuit cards can be resoldered to reconfigure
pre-EQ and/or pre-ON as required.

Stereo channel AUX options The stereo channel aux sends sum the channel
left and right signals as standard. Links can be resoldered so that the left signal
feeds sends 1, 3, 5, and the right feeds 2, 4, 6. One pair of links affects all pre­fade sends, another all post-fade.

Mono channel DIRECT outputs These are sourced post channel fader as
standard. A link on each card can be resoldered to reconfigure pre-fader. The
direct out pre-fade source is the same as that configured to feed the aux sends.

EXT input level option The external inputs are set for –10dBV line level as
standard. These can be reconfigured for +4dBu operation by cutting track links
on the connector card.

DIM switch function The DIM switch is set to mute the local monitor as
standard. This can be reconfigured to attenuate the signal by 20dB by cutting a
pair of track links on the right master circuit card.

Remote control of the DIM function The right master circuit card provides
solder pads to wire to the 25 pin REMOTE connector so local monitor DIM can
be activated by an external switch. Alternatively it can be wired to a mono card
so that pressing ON, PFL, or raising a switched fader can automatically mute
the signal. This can be used to mute the studio loudspeakers when the
presenter is on-air or checks his own microphone using PFL.

REMOTE user connector The blanking plate may be replaced with a
standard 25 pin chassis mount female D-connector for custom wiring.

Internally Fitted Option Kits

SYS-LINK output The blanking plate can be replaced with a 25 pin D-

connector with circuit card. This provides access to all the console outputs and
is compatible with any ALLEN & HEATH console already fitted with the SYS­LINK expander system.

RIAA option Up to three dual RIAA preamp circuit cards can be wired to the
connector assembly for direct connection to magnetic cartridge turntables.
Each card provides two stereo channels.

Switched fader option The standard mono and stereo faders can be
replaced by high grade Alps K-faders with fitted micro switches. These can be
wired to the 25 pin user connector to provide a remote start facility.

30 WZ20S User Guide

WZ20S CUE SHEET Photocopy and use to log your console settings

MixWizard

PAD

-30dB

40

30

GAIN

50

5k

7k

450

50

PAD

20

- 10

3060

100Hz

0

HFHF

12kHz

-15

+15

3kHz

1k

5k

700

15kHz

500Hz

0

MF1MF1MF1

-15

+15

180Hz

60

300

450

45

35Hz

1kHz

0

MF2

-15

+15

0

LF

60Hz

-15

+15

IN

AUX

1

0

0

0

0

0

0

+6

OO

AUX

2

OO

+6

AUX

3

OO

+6

AUX

4

OO

+6

POST

PRE

AUX

5

OO

+6

AUXAUX

6

OO

+6

POST

PRE

PAN

RLR

ON

PEAK

!

PFL

10

MIX1

5

MIX2

0

50

30

5k

7k

30060

450

0

00

0

0

0

0

PAD

-30dB

40

30

GAIN

PAD

- 10 20 3060

100Hz

0

12kHz

-15

3kHz

1k

700

500Hz

15kHz

0

-15 +15
180Hz

60

45

35Hz

0

MF2

-15 +15

0

LF

60Hz

-15 +15

IN

AUX

1

OO

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2

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4

OO

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OO5+6

OO6+6

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L RONL

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!

PFL

10

MIX1

5

MIX2

0

+15

300

1kHz

+6

+6

POST

PRE

POST

PRE

PAD

40

30

GAI N

PAD

- 10 20

60

100Hz

0

HF

12kHz

-15

+15

3kHz

1k

700

500Hz

15kHz

0

MF1

-15

+15

180Hz

60

45

35Hz

1kHz

0

MF2

-15

+15

0

LF

60Hz

-15

+15

EQ EQ EQ EQ EQ EQ EQ
IN

AUX

1

OO

+6

AUX

2

OO

+6

AUX

3

OO

+6

AUX

4

OO

+6

POST

PRE

AUX

5

OO

+6

AUX

6

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PRE

PAN

L

R

ON ON

PEAK

!

PFL

10

MIX1

5

MIX2

0

PAD

-30dB-30dB

40

30

GAI N

50

PAD

- 10

20

HF

12kHz

-15 +15

1k

700

500Hz

-15

45

35Hz

MF2

-15 +15

LF

60Hz

-15 +15

60

100Hz

0

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0

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1kHz

0

0

30

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7k

300

450

IN

AUX
1

0

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2

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3

0

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4

0

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MIX2

0

5 5

0

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0

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15

20

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0

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+15

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+15

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0

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+15

-150+15

0

LF

60Hz

+15

-15 +15

IN

AUX
1

0

AUX
2

0

AUX
3

0

AUX
4

0

AUX
5

0

AUX
6

0

BAL

PFL

MIX1

MIX2

AUX

1

0

OO

+6

OO +6

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2

0

OO

+6

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3

0

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O

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4

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PEAK

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5

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10

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10

5

10

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0

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0

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!

10

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0

0

0

0

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0

0

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0

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0

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15

0

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0

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0

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-15

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0

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60Hz

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IN

AUX

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2

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15

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+15

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0

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+15

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0

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+15

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0

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60Hz

+15

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IN

AUX

1

0

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2

0

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+6

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3

0

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4

0

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AUX

5

0

+6

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6

0

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R

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!

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10

MIX1

5

MIX2

0

10 10

20 20

0

0

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10

5

5

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5

0

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0

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15

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+15

-15

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-15

+15

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+15

-15

0

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-15

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IN

AUX

1

0

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2

0

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3

0

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0

OO

+6

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0

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0

OO6+6

POST

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BAL

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!

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10

MIX1

5

MIX2

0

5

10 10

20 20

5

0

GAIN

-5

-10

0

GAIN

-5

0

HF

12kHz

-15

0

MF1

-15

0

MF2

-15

0

LF

60Hz

-15

5

MONO

POWER ON

10

15

20

20

+15

+15

+15

+15

MIX1

MIX2

10

EXT1
IN

15

0

OO+6

+16

+9

+6

+3

0

-3

-6

-9

-12

-16

-20

-30

R

L

MIX1

IN

AUX

1

OO

AUX

2

OO

AUX

3

OO

AUX

4

OO

AUX

5

OO

6

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MIX1

MIX2

AUX

1

0

+6

0

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0

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0

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10

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2

3

4

5

6

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MIX1

10

5

0

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PFL

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0

10

20

EXT2
IN

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PFL PRG

MONITOR

PFL

4

3

2

1

010

1

1-2

2

3

3-4

4

5 AUX5

5-6

6

4

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0

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5

AUX1

AUX2

AUX3

AUX4

AUX6

EXT1

EXT2

MIX1

PFL ENABLE

5

1

0

SPLIT PFL

R

6

LEV

7

8

9

ALL UP =

MIX2

6

LOCAL

7

MONITOR

8

91

DIM

WZ

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30

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STEREO

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STEREO

WZ20S User Guide 31

30

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L
E
V
E
L

-

N
IO

T
P
O

+

-

u

B
d
4
+

V

+

B
d

=

0

IP

1

T

-

R

D
E
C
N
A
L
A
B

32 WZ20S User Guide

WZ20S User Guide 33