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7. NOMENCLATURE AND FUNCTIONS
[Front]
123 4 5
DA-550F
DA-500F-HL
1. Power switch [ ON/OFF]
Power is switched on and off with each depression
of this switch.
2. Power indicator [POWER]
Lights blue when the power is switched on.
3. Input level controls
[CH 1/BRIDGE 1, CH 2, CH 3/BRIDGE 2, CH 4]
Adjust the input level of each channel.
4. Ventilation panel (Air Vent)
A filter is located inside the ventilation panel.
To clean the filter, remove the ventilation panel.
(See p. 14; Cleaning the Filter.)
5. I
ndicators [INPUT, OUTPUT, PEAK, PROTECT]
The indicators are as follows from left to right:
• Input indicator [INPUT]
Lights green regardless of the input level
control setting when an input signal level
exceeds about –20 dB.
• Output indicator [OUTPUT]
Lights yellow when an output level exceeds
about 1 W at an 8 Ωload (DA-550F) or 9.8 Ω
load (DA-500F-HL).
• Peak indicator [PEAK]
Lights red when an output signal clips
(distortion occurs).
• Protection indicator [PROTECT]
Lights red when the protection circuitry is
activated. (See p. 13; Protection Operation
List.) When the power is switched on, this
indicator lights for about 2 seconds and then
extinguishes.
When a bridge connection is made
• When Channels 1 and 2 are bridge-connected
(BRIDGE 1 ON/OFF switch (10) is set to ON),
the CH 1/BRIDGE 1 level control adjusts the
input levels of Channels 1 and 2. In this event,
the CH 2 level control cannot be used.
• When Channels 3 and 4 are bridge-connected
(BRIDGE 2 ON/OFF switch (10) is set to ON),
the CH 3/BRIDGE 2 level control adjusts the
input levels of Channels 3 and 4. In this event,
the CH 4 level control cannot be used.