Toa A-903A, Operating Instructions Manual, Page: 5 / 15

Output Connections P-906A, P-912A
The speaker outputs of the amplifier are 4 , 8 , 25V and 70V.
Connect speakers to one of these outputs.
Class 2 wiring may be used.
Since these outputs consist of 8 , 25V and 70V via the output
transformer (matching transformer) and direct output of 4 , the
connecting method differs in each case. See the following diagrams:
Note: Impedances indicated below imply total speaker system
(load) impedances.
When connecting speakers to any one of the outputs of 8 , 25V
or 70V (BALANCED TRANSFORMER OUTPUT);
(A-906A)
(A-912A)
Note:
In this case, the LOW-CUT SWITCH should be in "CUT" posi-
tion. This amplifier is characteristically flat even in the low
frequency range. Therefore, in TRANS OUTPUT, the acoustic
effect and frequency-response characteristics may be altered.
In TRANS OUTPUT, cut off unnecessary low frequency to
obtain the best acoustic condition.
When connecting speakers to the 4 output. (UNBALANCED
DIRECT OUTPUT);
(A-906A, A-912A)
Installation
Do not block cover ventilation holes.
The amplifier should not be placed in areas;
1 with poor ventilation.
2 exposed to direct sunlight.
3 with high ambient temperature or adjacent to heat-generating
equipment.
4 with high humidity or dust levels.
5 susceptible to vibration.
Note:
When the temperature of heat sink exceeds 105°C, the protec-
tion circuit is activated and the output is disconnected from the
circuit. The signal automatically begins to be output as the
temperature goes down. In such a case, confirm whether or not
unit is overloaded or operated on an excessive output.
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