INSTALLATION AND CONNECTION
jhe Peavey lA 400 commercial series power amplifier is designed for durability in commercial installations,
as well as for the quality and performance required in studio applications. The unit is a standard rack-mount
configuration, 3-1/2" high, and is cooled by an automatic two-speed internal fan. All the input and output
connections are on the back panel. The front panel contains LED indicators for power and SPS activation,
and a mains power switch.
STUDIO INSTALLATION
In most low to medium power applications, the lA 400 can be mounted in any configuration. If at all possible,
the unit should be located at the top of an equipment stack. This will prevent possible overheating of any
sensitive equipment by hot air rising from the power amplifier. As a general rule, most studio requirements
should never cause a thermal shutdown of either channel; however, if it does, this may indicate that you
have not taken the necessary steps to provide adequate cooling. Remember closed up in a cabinet, the
lA 400 will have severe cooling problems, even at low levels. Again, inadvertent short circuit or sustained
overloaded usage could also cause temporary thermal shutdown.
INDUSTRIAL AND COMMERCIAL INSTALLATION
For commercial and other installations where sustained high power operation is required, the amplifiers
should be mounted in a standard 19" rack. It is not necessary to leave a rack space between each amplifier
in the stack, since the fan pulls air in from the rear and exhausts the hot air from the front. An adequate
"COOL" air supply must be provided for each amplifier when rack-mounted. The internal fan must have a
source of air that is not preheated by other equipment. If cooling is inadequate due to preheated air or use in
a high temperature environment; or if the amp is severely overloaded or shorted, the unit's thermal sensing
system may cause temporary shutdown of that particular channel. If this occurs, it is best to switch the
amplifier off—it will cool down quicker this way. Corrective action should be taken to determine the cause of
the thermal shutdown. If the unit is not severely overloaded or shorted, then steps should be taken to pro¬
vide a cooler environment for all the amplifiers. As a general rule, the cooler electronic equipment is oper¬
ated, the longer its useful service life. You have invested in the finest equipment that money can buy, and a
little care will ensure long and reliable operation.
BRIDGE MODE
The Bridge mode on stereo power amplifiers is often misunderstood as to the actual operation and usage. In
basic terms, when a 2-channel amplifier is operated in the Bridge mode, it is converted into a single channel
unit with a POWER RATING equal to the sum of both channels' power ratings at a LOAD RATING of twice
that of the single channel rating. In this case, the lA 400 is rated at 200 watts RMS into 8 ohms. The
BRIDGE RATING is 400 watts RMS into 16 ohms.
A 70 volt line Stereo mode at 200 watts with a load of 24 ohms each channel will become 140 volt line at
400 watts with a recommended load of approximately 48 ohms in the Bridge mode. Bridge mode operation
is accomplished by depressing the mode switch to the "in" position, connecting the load between both
channels' OUT outputs, using channel A as the input channel. All channel B functions are now defeated and
serve no purpose. To maintain correct phasing, the positive speaker terminal should be connected to the
OUT output on channel A.
ARCHITECTURAL & ENGINEERING SPECIFICATIONS
The power amplifier shall have one input per channel with provisions for balanced and unbalanced signals.
Connections for the balanced inputs shall be provided via a 3-terminal barrier strip. Connections for the
unbalanced inputs shall be provided via a 3-terminal barrier strip, by shorting the (-) input to ground. This
amplifier shall be capable of delivering over 200 watts RMS into 8 ohms and over 240 watts RMS into
4 ohms with both channels driven. This amplifier shall be able to drive 70 volt distributive line systems
directly without the need for an output transformer, thus producing over 200 watts per channel. This amplifier
must provide SPS distortion elimination circuitry, and the output must be easily bridged. This amplifier shall
be fully compatible with the Peavey MediaMatrix® system with addition of an input module. This amplifier
shall be capable of delivering 20 Hz to 20 kHz +0, -0.3 into 4 ohms at less than 0.1 % THD with a signal-to-
noise ratio of at least 100 dB below rated output. The unit shall be called the Peavey Architectural Acoustics
model lA^'^ 400.