Toa A-912MK2 - Manual (Page 9)

9
DIRECT
4Ω 8Ω
70V
25V
COM
4 Ω
25 V line (21 Ω)
70 V line (167 Ω)
Impedance selector switch
1, 3
2
6.2. Speaker Connections
The unit has 25 V and 70 V outputs for constant voltage speaker system and low impedance output for 4 Ω or
8 Ω speaker loads.
Two types of speaker output are available: transformer-balanced output and unbalanced direct output, which
can be selected by the Impedance selector switch.
Connect the speaker system to only one of the speaker outputs. Class 2 wiring may be used.
The speaker connection method differs with amplifier models and their applications.
Refer to the following connection diagrams described for each model. Impedances indicated in the diagram
mean total speaker load impedance.
6.2.1. A-903MK2: Speaker connection to transformer-balanced output
Step 1. Unscrew the terminal cover.
Step 2. Strip 10 mm (0.39") of insulative jacket from the end of the speaker cable,
as shown in the figure at right.
Step 3. Connect speaker cables to the speaker output terminals.
Step 4. Replace the terminal cover.
10 mm
(0.39”)
[Connection of speaker cable]
[Impedance selector switch setting]
Step 1. Loosen the screw.
Step 2. Shift the impedance selector switch to "4 Ω" position.
Step 3. Retighten the screw.
[Low-cut switch (on the front panel) setting]
It is highly recommended that the low-cut switch be placed in the ON position to cut off unnecessary low
frequency. This is because the built-in transformer cannot produce low frequencies though the unit has flat
response even in low-frequency range.
This type of output allows speaker connection to one of 4 Ω, 25 V, or 70 V terminal.
Be sure to replace the terminal cover after connection completion.
Because high voltage is generated at the speaker output terminals,
never touch these terminals to avoid electric shock.
WARNING
The terminals marked with the symbol are hazardous live.
The external wiring to these terminals requires installation by an
instructed person.
WARNING