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Figure 3. Driver Card Modules for the Incremental Power System
POWER AMPLIFIER MODULES
Up to eight Model 2275 Power Amplifier
Modules may be inserted in the main frame
for the desired power rating and power con-
figuration. The power amplifier modules are
rated at 75 watts each and may be combined
in 75-watt increments for up to 600 watts
output power from each main frame system
.
Power output level and power distribution
configurations
may be selected to meet
most audio applications. Figure 4 illustrates
the Model 2275 Power Amplifier
Card
Module.
Typical operating
configurations
of the
Model
2275
Power
Amplifier
Module
include:
• Independent
mode for separate
loud-
speaker loads.
• Parallel mode to increase output power in
increments of 75 watts for higher power,
low impedance loads
.
·
•
I;!
ridged mode to drive balanced 70-volt
lines. Two power amplifier
modules,
driven out-of-phase
to
each other, have
the loudspeaker load connected to the
'hot' terminals of the two modules. Power
available is 150 watts.
• Parallel-bridged
mode to drive higher
power balanced 70-volt lines, or other
high power loads
.
Two sets of parallel
power amplifier modules may be bridged
Model 2275
Model 2276
Figure
4.
Model Power
Amplifier
Card Modules
3
to
obtain maximum output power ratings
of 300
watts
(2 sets of 2
modul_
es),
450
watts (2 sets of 3 modules)
,
or 600 watts
(2 sets of 4 modules).
Up to
4
Model 2276 Model 2276 Power Amp-
lifier Modules may be inserted in the main
frame for the desired power rating and
power configuration.
Each module is rated
at 150 watts. The modules may be combined
in 150-watt increments for up to 600 watts
output power from each main system
.
Oper-
ating
configurations
are similar
to the
model 2275 Power Amplifier Module
,
except
for the power rating of 150 watts per mod-
ule
.
Figure 4 illustrates
the Model 2276
Power Amplifier Card Module.
Typical
operating
configurations
of
the
Model
2276
Power
Amplifier
Module
include:
•
Independent
mode for separate loud-
speaker loads.
•
Parallel mode to increase output power in
increments of 150 watts for higher power,
low impedance loads
.
Power available is
300,
450,
or 600 watts
.
•
Bridged mode to drive balanced 70-volt
lines
.
Two
power
amplifier
modules,
driven out of phase to each other, have
the
loudspeaker load connected to the
'
hot' terminals of the two modules
.
Power
available is 300 watts.
•
Parallel-bridged
mode to drive higher
power
,
balanced 70-volt lines, or other
high power loads
.
Two sets of parallel
power amplifier modules may be bridged
to obtain an output power of 600 watts
.
If fewer than four Model 2276 modules are
used in a main frame system, Model 2275
Power Amplifier Modules may be installed
in remaining power module positions. The
Models 2275 and 2276 modules may be used
in independent
modes, or intermixed in
various combinations of parallel, bridged, or
parallel-bridged modes
.
As shipped from the factory
,
the main frame
and each power amplifier module operate
into a load impedance of 16 ohms
.
By
selecting other taps on the ac power trans-
former of the main frame and removing two
jumper
leads of
each power amplifier
module, the main frame system can operate
into a load impedance
of 8 ohms. For
parallel and bridged configurations
,
speci-
fic loudspeaker load requirements are
dis-
cussed within the installation portion of the
instructions.
INSTALLATION
VENTILATION
The Incremental Power System must be ad-
equately ventilated
to
prevent
excessive
·
temperature rise
.
Maximum rated ambient
operating temperature is 55°C (131
°F).
------
CAUTION------,
Do not block the side ventilation
apertures on either side of the main
frame
.
Allow at least
2"
on each side
of the main frame to assure adequate
ventilation.
Do not operate within a
completely
closed,
unventilated
housing.
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