Facilities; Front Facilities - Crown Macro-Tech MA-5000VZ Reference Manual

2 Facilities

A. Dust Filters
The dust filters remove large particles from air drawn in
by the cooling fans. Check the filters regularly to pre-
vent clogging (see Sections 3.2 and 4.5).
B. Level Controls
The output level for each channel is set with these con-
venient front panel level controls. Each control has
31 detents for precise adjustment (see Section 4.4). A
security option is also available to prevent tampering
(see Section 8.2).
C. I /I Indicators
Load Limit
The flow of current to the loudspeakers ("load current")
and the maximum current limit of the amplifier ("limit
current") are monitored by these two-color front panel
indicators. Normally, the I
green to show that load current is flowing. They turn off
when there is no significant load current. This happens
when there is no input signal, the input signal is at an
extremely low level, or there are no loads connected to
the amplifier's outputs. They turn red if the amplifier has
reached its maximum output current capacity.
The I /I indicators are very useful when loading
Load Limit
the amplifier for maximum output. Just continue to con-
nect additional loudspeakers in parallel with each output
until the I /I indicator turns red under normal op-
Load Limit
erating conditions. The optimum load is achieved just be-
fore the indicator turns red (see Section 4.2).
D. Signal/ IOC Indicators
These green multifunction indicators show both signal
presence and distortion for each channel. As signal
presence indicators, they flash synchronously with the
amplifier's audio output. As IOC (Input/Output Com-
Page 10
Fig. 2.1 Front Facilities
/ I indicators glow
Load Limit
Macro-Tech 5000VZ Power Amplifier
parator) indicators, they flash brightly with a 0.1 sec-
ond hold delay if there is a difference of 0.05% or more
between the input and output audio waveforms. IOC
"errors" occur most commonly when a large input sig-
nal causes an input overload or output clipping. The
IOC function is also provided as proof of distortion-free
performance (see Section 4.2).
E. 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 re-
serves are depleted, the indicators turn off and ODEP
proportionally limits output drive so the amplifier can
safely continue operating even under severe condi-
tions. These indicators also help to identify more un-
usual operating conditions (see Section 4.2).
F. Enable Indicator
This indicator lights when the amplifier has been turned
on (enabled) and has AC power (see Section 4.2).
G. Enable Switch
This push button is used to turn the amplifier on and
off. When turned on, the output is muted for about four
seconds to protect your system from start-up tran-
sients. This is why a power sequencer is rarely needed
for multiple units. (The length of the turn-on delay can
be changed. Contact Crown's Technical Support
Group for details.)
H. VZ Mode Switches
A four-position switch is used to control the switching
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