INTRODUCTION
A mixer amplifier with 6 selectable microphone or line inputs and phantom power, chime
function on CH1 and VOX priority on CH1 & CH2. Provision for the connection of 100V line or
low impedance loudspeakers. It also features a slave output and send/return for connection of
an effects unit. The amplifier can be powered from either 230Vac or a 24Vdc power source.
WARNING: THIS APPLIANCE MUST BE EARTHED
1. Channel ( 1-6 ) volume controls.
2. Bass and treble cut & boost controls
3. Master volume control
4. Power, Signal and Peak LED indicators
5. Power ON / OFF switch
6. Fused IEC mains input socket
7. Ground terminal
8. DC (24V) Input terminal
9. Loudspeaker output terminal block
10. Low impedance ( 8 & 16Ω ) loudspeaker 6.3mm jack sockets
11. Send/return effects 6.3mm sockets
12. Slave out RCA phono socket
13. Channel 1 Input. Features: Combination XLR / 6.3mm socket, RCA phono sockets,
terminal block for hard wiring of microphone & chime function, DIP switch for
selection of Mic/Line, VOX, chime & phantom power
14. Channel 2 Input. Features: Combination XLR / 6.3mm socket, RCA phono sockets,
DIP switch for selection of Mic / Line, VOX & phantom power
15. Channel 3-6 Inputs. Features: Combination XLR / 6.3mm socket, RCA phono sockets,
DIP switch for selection of Mic/Line & phantom power
LOUDSPEAkERS
All connections to the loudspeaker terminals should be made using suitable connectors
crimped or soldered to the speaker cables. Any other method can give rise to short circuits.
There is provision for 70V or 100V line and low impedance loudspeakers, but different types
must not be used on the same installation. In addition to the terminal block there are two
6.3mm jack sockets for connection of low impedance ( 8 and 16 ohms) loudspeakers. Low
impedance speakers can be connected in series, parallel or a series/parallel arrangement to
give the correct loading. Care should be taken with this set up in that the volume level is
carefully controlled, as it is possible to damage speakers by using too high a volume setting.
100 volt line should be connected to the COMMON and 100V terminals taking care that the
sum of the wattage of all the loudspeakers on the line does not exceed the total power
available from the amplifier. NOTE: It is good practice to allow a headroom of 10% when doing
your calculations. With 100 volt line installation all the speakers must be wired in parallel.
Please note that the loudspeaker terminals are fully floating with respect to chassis. In the
event of cross talk to other services or instability, then it may be beneficial if the COM terminal
is strapped to the earth binding post. Also note that a low impedance system requires heavy
duty cable feeding the loudspeakers to minimise losses. For a widespread installation it is far
better to use a 100 volt line system.
INPUT/OUTPUT CONNECTIONS
Each input has both balanced ( microphone/line ) combination XLR/6.3mm
and unbalanced (line only) RCA phono with DIP switches for selection of
microphone or line and phantom power.
Channel 1 has additional 3 pole screw terminal block for hard wiring a balanced microphone.
Chime activation is also provided by a DIP switch on CH 1, as well as a 2pole terminal block.
The chime is two tone (550Hz & 650Hz) and has the highest priority (Priority 1) and on
activation mutes all input signals. (Note: for full priority the VOX switch must be in the on
position) The chime is activated by external switch closing.
Microphone 1 overrides CH 2-6 inputs when the VOX switch is on (Priority 2 )
Microphone 2 overrides CH 3-6 inputs when the VOX switch is in the on position (Priority 3)
SLAVE out RCA phono socket is for connection to an additional booster amplifier.
ADDENDUM: The marking of the CHIME dip switch is incorrect. To activate the CHIME function
the switch must be in the 'OFF' position. Any further enquires please contact our technical
department.
The SEND and RETURN 6.3mm sockets are for connection of an effects unit. Loudspeaker
outputs are via a screw terminal block or 6.3mm sockets.
A 24 volt battery can be connected using suitable connectors crimped to the battery terminals.
Observe the correct polarity. NOTE : The power switch does not control the 24V supply to the
amplifier. The mains input is a fused IEC 3 pin socket.
SETTING UP
When all connections have been made, check that all the controls are at zero then plug the
mains lead provided into the amplifier and the 13 amp plug into a suitable 230 volt socket.
Depress the power switch on the front panel and the POWER LED illuminates.
Advance the MASTER control to 6 on its scale then using a local microphone in CH 1 input
slowly advance its volume control whilst speaking into the microphone. Observe the SIGNAL
indicator. As the control is advanced the indicator will start flashing in time with the peaks of
speech. This indicates that a signal is being passed to the loudspeakers. The control should be
set so that the peaks of sound keep the SIGNAL indicator almost continuously lit but the PEAK
LED only shows on rare occasions or not at all. Continuous illumination of the PEAK LED
indicates the amplifier is being overloaded.
If the MIC 1 control is at maximum without achieving the desired output then it will be
necessary to increase the MASTER setting a little and recommence the setting up procedure
until a satisfactory level of output is achieved.
It may be that before this setting can be achieved a howl – round (feed back) point is reached
where the system appears to become unstable, if this is the case then the nearest loudspeaker
and the microphone you are using are in each others sound fields and need to be repositioned.
If a 100 volt line system is being employed you can reset the nearer loudspeaker to a lower
wattage tap to minimise the howl-round (feed back).
The object of this setting up procedure is to balance the MASTER and MIC 1 controls so neither
are at a very low or a very high setting in relation to each other. When the initial set up is
completed try the other channels in the same way.
Most tape and CD players have additional level controls of their own which can be usefully
used to fine balance their volume levels with the LINE controls.
The bass and treble controls should initially be set to their minimum (anti-clockwise) positions
for setting up. Once this has been carried out then the tone controls can be set for personal
preference.
INTERFERENCE
Whilst this equipment complies in all respects with EMC legislation its use in an industrial
environment where there are many potential sources of interference means that steps may
need to be taken to minimise any problems. Always check that the amplifier has a good earth.
In the event of interference secure the services of a qualified electrician to carry out tests on
the socket to ensure a low resistance earth path exists.
DO NOT
run microphone cables near mains, data, telephone or 100V line cables
DO NOT
run 100V line cables near data, telephone or other low voltage cables
DO NOT
position the amplifier very close to large transformers, TV monitors and computers
AVOID
jointing the microphone cable, when this is unavoidable ensure
a good screened connector is used eg. XLR
ALWAYS
use a balanced microphone terminating in a
balanced input on long microphone cable runs
ALWAYS
use mains grade double insulated cable for 100V line cable runs
GB
WARNING: DO NOT CONNECT THE MAINS SUPPLY TO THE AMPLIFIER UNTIL ALL THE NECESSARY
INPUT AND OUTPUT CONNECTIONS HAVE BEEN MADE.
CIRCUIT DIAGRAMS ARE AVAILABLE ON REQUEST
AMPLIFIER MANUAL
CH-1
A126
MIXER AMPLIFIER 120W
CH-1
CH-2
CH-3
CH-4
CH-5
CH-6
CH-6
L
R
PHANT
OM
OFF
MIC
LINE
+VE
-VE
SCREEN
+2
-3
CH-5
L
R
PHANT
OM
OFF
MIC
LINE
+VE
-VE
SCREEN
+2
-3
CH-4
L
R
PHANT
OM
OFF
MIC
LINE
SCREEN
+VE
-VE
+2
-3
CH-3
L
R
PHANT
OM
OFF
MIC
LINE
+VE
-VE
+2
-3
CH-2
L
R
VO
X
OFF
PHANT
OM
OFF
MIC
LINE
SCREEN
+VE
-VE
+2
-3
L
R
VO
X
OFF
CHIME
OFF
PHANT
OM
OFF
MIC
LINE
SCREEN
+VE
-VE
+2
-3
CHIME
+
-
GND
SLAVE OUT
RETURN
SEND
SPEAKER
8Ω
16Ω
OUTPUT
COM 8Ω 16Ω 70V 100V
SCREEN
SIG
-
+
SPEAKER
CONNECTIONS
24Vdc
+ -
Stock code: 952.997UK
110V / T4A
240V / T2A
110V~60Hz
240V~50Hz
CAUTION
DO NOT OPEN. NO USER
SERVICABLE PARTS INSIDE.
RISK OF ELECTRIC SHOCK
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