Specifications

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 amplifier is set up for
power sequencing (see the section on power sequencing), 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 break-
er 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 indicators
for each channel.
LIMIT - When illuminated, it indicates a condition in which the amplifier is
limiting and automatically reducing signal level to reduce the overload con-
dition. 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 oper-
ational ranges.
SIGNAL - When illuminated, it indicates that there is signal at the output.
STATUS - Illuminates in three different colors to indicate current opera-
tional 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
disconnected 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 Low Cut Filter allows a low frequency roll-off starting at 60 Hz to be
introduced into the signal path preventing the speakers from receiving too
much low frequency content. The Low Cut Filter Switch should be turned
ON when using typical inexpensive, transformer-coupled cone-type speak-
ers 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 20 Hz. This extended low frequency opera-
tion can be troublesome for some transformer-coupled speakers used in
70V audio systems. Relatively inexpensive transformers used in some speak-
ers cannot handle frequencies below 60 Hz. 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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