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Operation
Front Controls & Indicators
Power Switch
The Power Switch for the Black Max amplifier is located on the front
of the unit. Press the "I" side of the switch to turn the unit ON. The
amplifier will begin its power up process once turned on. If the amplifi-
er is set up for power sequencing (see the section on power sequenc-
ing), the amplifier may not begin its power up process but rather wait
in a standby state until it receives a sequence trigger.
The Power Switch is also the amplifier’s circuit breaker. Should the
breaker trip, simply place it in the OFF position and then back to ON
to reset the breaker.
Note: If the Power Sequencing Switch is in the ON position, but the wiring
is not properly configured, the unit will appear dead. Review the Sequential
Turn-On section for proper wiring.
Front Indicators
The front of the Black Max amplifier contains 3 different types of indi-
cators for each channel.
LIMIT - When illuminated, it indicates a condition in which the ampli-
fier is limiting and automatically reducing signal level to reduce the
overload condition. Limiting is a result of speaker load impedances that
are too low or input signals that are too high, which drive the outputs
beyond their operational ranges.
SIGNAL - When illuminated, it indicates that there is signal at the
output.
STATUS - Illuminates in three different colors to indicate current
operational status of the amplifier.
Green - Indicates that the amplifier is operating normally.
Amber - Indicates that the amplifier is in Sleep mode.
Red - Indicates a fault condition and that the amplifier has dis-
connected the output load as a safety precaution.
Rear Controls & Indicators
Level Controls
Use the rear-mounted Level Controls on the Black Max amplifier to
adjust output volume of each channel independently.
Lo-Cut Switch
The Lo-Cut filter allows a low frequency roll-off starting at 60Hz to be
introduced into the signal path preventing the speakers from receiving
too much low frequency content. The Lo-Cut Filter Switch should be
turned on when using typical inexpensive, transformer-coupled cone-
type speakers found in paging systems.
The Black Max amplifier is a direct-coupled amplifier, which means that
there are no output transformers used to deliver the 70V audio to the
speakers. Because of this, the Black Max amplifier has a flat frequency
response down to and below 20Hz.This extended low frequency oper-
ation can be troublesome for some transformer-coupled speakers used
in 70V audio systems. Relatively inexpensive transformers used in some
speakers cannot handle frequencies below 60Hz. When frequencies
lower than this are applied to these speakers’ transformers, they can
saturate causing distortion and high instantaneous power consumption.
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