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ably soldered, can be inserted into the hole in the terminal post and the plastic cap should be screwed
down tightly onto the cable or lug. Please consult your dealer if you are unsure.
It is very importantto connect the loudspeakers to the loudspeaker sockets in the correct phase,
or polarity. The positive and negative sides of the cable should be connected to the loudspeaker in
the same way for each channel. If it is connected out of phase, or the polarity is changed, a severe
loss of bass performance and a spreading of the stereo image will result.
It is not recommended to use loudspeakers of less than 4
Wresistance or more than two pairs of
8
Wspeakers running from the amplifier at one time. However, bi-wiring of one pair of speakers,
using the four terminal posts, can improve the sound of your system (consult your dealer for more
details). Terminals A and B are both connected to the output of the amplifier, via high current
switching relays selected from the front panel switch.
N.B.
It is VERY IMPORTANT not to short the loudspeaker cables together when the other ends are
still connected to the working amplifier as permanent damage may result.
If it is necessary to move or change the location of your loudspeakers, make sure that you
SWITCH OFF the amplifier from the mains first.
STANDARD INPUT CONNECTION
There are 8 shielded RCA type jack sockets on the rear panel. This is, needless to say, more
than the normal quantity found on a regular stereo amplifier. The A52 is, however, more than a
regular power amplifier as, whilst it provides inputs for LEFT and RIGHT channels, it also pro-
vides inputs for both Positive and Negative Phases, and two input-output sockets for each phase
and channel. The reason is to increase its flexibility. The coupled input-output sockets allow for
the input signal from the pre-amp to be patched to another A52 power amplifier for bi-amped sys-
tems and for forming a link from one channel to the other in mono configuration. Positive and
Negative inputs allow for balanced input operation in stereo and the possibility to bridge the A52
into mono mode. The A52 will, of course, operate as a simple stereo amp.
INPUT CONNECTION FOR NORMAL STEREO OPERATION
Where a single A52 is used to drive a single pair or bi-wired pair of loudspeakers in stereo, it is nec-
essary to input a signal from the source, in the normal way, via a pre-amp or control unit, to either the
left or right positive phase inputs, marked + 1 RIGHT INPUT and +1 LEFT INPUT.
PARALLEL INPUT-OUTPUT CONNECTION
Paralleled in-out sockets make it easy to connect two or more A52s together in a chain for dedicated
multi-amp systems or for high-end AV systems. See wiring diagram for multiple connection.
BRIDGED DUAL MONO CONNECTION CONNECTING THE LOUDSPEAKERS
A further A52 amplifier will be required for stereo operation. Each A52 amplifier should be wired
to drive a single channel only, either left or right. Each loudspeaker should be wired between the
left live (RED) and right live (RED) output terminals on the rear of each amplifier. Phasing of the
leads is still important and, therefore, if the positive (ribbed) wire is connected to the right connec-
tor on one channel (Right) it should be wired to the same connector on the other channel.
Bi-wiring is still possible, by using A and B terminals, but it is not advisable to connect more than
one 8Wspeaker to a Bridged A52 at a time, as the amplifier will try to increase its power output
to a level that could overheat and possibly damage it. Do not connect either loudspeaker wires
to any ground terminals (BLACK) or the bridging mode will be defeated. When wiring the A52 in
Mono mode is necessary to configure the input in a special way also. See wiring diagram for
bridged mono mode.
N.B.
It is VERY IMPORTANT not to short the loudspeaker cables together when the other ends are
still connected to the working amplifier as permanent damage may result.
If it is necessary to move or change the location of your loudspeakers, make sure that you
SWITCH OFF the amplifier from the mains first.
INPUT CONNECTION FOR BRIDGED MONO OPERATION
If the A52 is required to run in Bridged Mono mode, it is necessary to input a signal from the source,
in the normal way, via a pre-amp or control unit to both of the A52s amplifiers which are joined in a
bridge. Input the source signal to + RIGHT input 1 (the 1st right channel positive input). This con-
nects the signal to one half of the bridge. Then use a very short interconnect (10 - 20 cm) cable
between + RIGHT input 2 (in parallel with the input 1) and - LEFT input 1 (the 1st left channel nega-
tive input) to link the input signal to the other half of the bridge.
Both of the A52s amplifiers now share the input signal, each capable of amplifying half of the sig-
nal. However, to properly balance the signal and gain maximum efficiency (symmetry) and
sound quality, it is necessary to short the unused positive and negative inputs with a special ter-
minating stub or shorting RCA jack plug. Creek part # RCA-STUB.Using 2 x RCA-STUBs,
plug the first into + LEFT input 2 and the second Stub into - RIGHT input 1.
For further information, see wiring diagram for Bridged Mono Operation.
STEREO BALANCED MODE INPUT CONNECTION
It is possible to input the A52 with a fully balanced signal from a Pre-amp with balanced output
capability.
OPERATING THE A52
Make sure that the unit is on a suitable table or Hi-Fi equipment cabinet. It is important to allow
adequate ventilation to the heatsink in the centre of the unit. Avoid obstruction of the ventilation
slots on the top cover. It may be necessary to place the amplifier on the top of other equipment
to allow for this.
To switch on the A52 press the switch, marked POWER, on the right hand side of the front panel. The
rotary switch on the left hand side of the front can select speaker outputs A, B or A+B, or off.
The rotary control next to the speaker switch, marked TUNING, allows the user to adjust the point
at which the low frequency response of the A52 rolls off. The TUNING point should be adjusted
up or down to provide more or less extreme bass and also to affect the space and depth of the
stereo image. TUNING will not produce a dramatic effect, as it only alters sub-sonic frequencies.
To indicate the status of the amplifier, when the amplifier is first switched on, the POWER LED
indicator should glow orange. When the amplifier reaches operating condition, the Power LED
will switch to green. However, if a fault condition is detected the relay will switch speaker outputs
off and the POWER indicator will glow red.
To protect the loudspeakers connected to the amplifier from dangerous DC voltages, there is an
internal 10 Amp relay for each output A and B. They operate after a short delay at switch-on but are
instantaneous at switch off, to avoid unpleasant noises. Short circuiting the output should be avoid-
ed at all costs. However, over-current and short circuit protection in the A52 will monitor the condi-
tion and disengage the output relays, should it be necessary.
Your A52 amplifier is designed to give you years of reliable use. However, it is necessary to take care of
your possession, so never overheat it or short out the speaker connections. If an adjustment is needed,
it is always advisable to return it to the supplying dealer for his expert help. If you are unfortunate
enough to need service work to be carried out on your amplifier, it should be returned to your dealer or
the manufacturer in the original packing material if possible.
