User Manual

Allen & Heath 28 WZ
4
16:2 and 12:2 User Guide
AUX master balance option The 6 aux
outputs are impedance balanced as standard operating at
nominal -2dBu and with +21dBu maximum drive. They
provide similar interference rejection to electronically
balanced outputs when connected to balanced equip-
ment inputs. An electronically balanced option is availa-
ble if you require nominal +4dBu and higher output
drive up to +26dBu over very long cable runs. Howev-
er, it is not usually necessary to fit this option as the
impedance balanced drive satisfies most applications.
Check that you really need the option before fitting it.
There are two balanced driver ICs which may be used.
Either is suitable. These are available from Allen &
Heath or most electronic component suppliers. The
Allen & Heath part number is shown below:
SSM2142 A&H Part AE0302
DRV134 A&H Part AE5725
For each aux master, snip the legs of the two zero ohm
resistor links as shown. This removes them from the
circuit. Now solder the option IC into the socket. Ob-
serve the correct IC pin1 orientation and make sure its
legs are correctly aligned with the socket. Test the out-
put once the work is complete. You should measure
the same level but opposite polarity signal between +
(hot) and ground, and – (cold) and ground.
NOTE: This procedure will require the use of a soldering
iron. If you have any doubts please contact Allen & Heath
and we will put you in touch with your nearest service cen-
tre.
USB OPTION A blanking plate is fitted over the
rear USB socket as standard.
A USB multi-channel option card is available, the part
number is shown below:
004-232JIT WZ4 USB AUDIO OPTION
This is a high quality audio card that sends 16 channels
from the mixer to a computer for recording or pro-
cessing. A stereo channel is returned to the mixer for
monitoring purposes or as an effects return path.
For the 12:2 the card sends the following channels to
the computer: Mono channels 1-8 direct out, Aux out-
puts 1-6, Left/right insert sends OR AB outputs.
For the 16:2 the card sends the following: Mono chan-
nels 1-14 direct out, Mono channels 15 & 16 direct out
OR AB outputs.
The ST2(ST6) source can toggled between the computer
return feed or the input sockets mounted at the rear of
the mixer.
For full details please refer to the WZ4 USB option
application note AP8987 and fitting instructions AP8988.
AUX MASTER - BALANCED OUTPUT OPTION
U12 U11 U10 U9 U8 U7
AUX6 AUX5 AUX4 AUX3 AUX2 AUX1
CUT OUT TWO RESISTOR LINKS
INSERT DRIVER IC
1
WZ
4
12:2
WZ
4
16:2
MULTICHANNEL AUDIO
USB 2.0
ST2 SOURCE
SENDS 15/16
MONO CH 15/16
AB
ST2 INPUT
USB RETURN
MULTICHANNEL AUDIO
USB 2.0
ST6 SOURCE
SENDS 15/16
LR INSERTS
AB
ST6 INPUT
USB RETURN