The MT250D Power Amplifier is a highly versatile, high-
power performer. It delivers 250 watts (rms) at less
than 2% distortion and is ideal for use where high
power and backup capability are required. The unit will
operate both from 120/240VAC (50/60Hz), and from a
24-volt battery backup system. It includes a battery
saver circuit which reduces idling power requirements
after at least 20 seconds of no signal.
The amplifier complies with UL standards for Fire
Protective Signaling Equipment (UL1711). The front
panel power switch is disabled so that the unit remains
on regardless of the position of the switch (an internal
jumper enables the switch for applications where this is
desired.)
The amplifier can handle input from a high-impedance
unbalanced source, balanced low-impedance source
(requires accessory transformer), or from a telephone
line. The impedance at the Hi-Z input is 50 kilohms,
nominal, and 600 ohms for the Lo-Z input (requires an
accessory transformer).
The input sensitivity is 1 volt for full rated output (Hi-
Z). The Lo-Z input sensitivity is 200mV with the input
selector switch in the HIGH LEVEL position, and 70mV
with the switch in the TEL LINE position. Provisions
are included for bridging input (requires an accessory
transformer).
Five output transformer taps are provided on the rear
panel: 12.5V, 25V, 8-ohm, 70.7V and 100V. A polarized
output receptacle is provided for the 100V output. A
low-cut filter switch and input level control are provid-
ed. The amplifier is protected from overload by fuses
on the AC and DC inputs, and by thermal and elec-
tronic circuits (includes a front-panel mounted elec-
tronic overload indicator).
The amplifier is housed in a sturdy 11-gauge metal
enclosure finished in flat black. The front panel is
designed with predrilled mounting holes for installation
in standard equipment racks.
Power Amplifier
With Battery
Backup
Capability
Model MT-250D
• 250 watts continuous (rms) output for a duration of 250 hours
• Listed under UL 1711 for Fire Protective Signaling Systems, registration number S2594(N)
• Life Safety features provide capability for 24V customer-supplied backup battery when primary power fails
• Battery-saver circuit reduces idle current to a low value after 20 seconds (minimum) of no signal
• Protection against line surges, overloads, and abnormal heat buildup
• LED overload shutdown indicator
• Switchable low frequency filter
• Unswitched AC convenience outlet (300 watts)
• Low impedance balanced input offers two sensitivity levels using accessory transformers
• Rack mountable in standard 19” EIA rack; 11-gauge metal housing with flat black finish
Features
Description
Specifications subject to change without notice.
© 1995 Bogen Communications, Inc.
Part No. 54-7824-03 Printed in U.S.A. 9509
