Crown ma-1202 ユーザーズマニュアル

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MA Series Power Amplifiers
Operation Manual
4.2 Front Panel Controls and
Indicators
The diagram below shows the controls and 
indicators on the front panel of the Macro-Tech 
02 Series. 
A. Dust Filters
The dust filters remove large particles from the 
air drawn in by the cooling fan. Check the filters 
regularly to prevent clogging. The filter ele-
ments can be easily removed for cleaning by 
gently pulling them away from the front panel.
B. Level Controls
The output level for each channel is set with 
these convenient Level controls mounted on 
the front panel. Each level control has 31 
detents for precise adjustment. A security 
option is available to prevent tampering (see 
Section 5.3.3).
C. Signal/IOC
®
 Indicators
These green multifunction indicators show sig-
nal presence and distortion for each channel. 
As signal presence indicators, they flash syn-
chronously with the output audio signals to 
show their presence. As IOC (Input/Output 
Comparator) indicators, they flash brightly with 
a 0.1 second hold delay if there is a difference 
of 0.05% or more between the input and output 
signal waveforms. This provides proof of dis-
tortion-free performance. Note: The Channel 2 
IOC indicator stays on in Parallel-Mono mode 
(see Section 3.6.3).
D. ODEP Indicators
During normal operation of the ODEP (Output 
Device Emulation Protection) circuitry, these 
amber indicators glow brightly to show the 
presence of reserve thermal-dynamic energy. 
They dim proportionally as energy reserves 
decrease. In the rare event that energy reserves 
are depleted, the indicators turn off and ODEP 
proportionally limits output drive so the ampli-
fier can safely continue operating even under 
severe conditions. These indicators can also 
help identify more unusual operating condi-
tions (see Section 5.1.1).
E. Enable Indicator
This indicator lights when the amplifier has 
been "enabled" or turned on, and AC power is 
available.
F. Enable Switch
This push button is used to turn the amplifier 
on and off. When turned on, the output is 
muted for approximately four seconds to pro-
tect your system from start-up transients. (This 
delay can be changed. Contact Crown's Techni-
cal Support Group for details.)
Figure 4.1   Front Panel Controls & Indicators
4 Operation