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INTRODUCTION
Thank you for your purchase of the ROLLS RA2100b Power Amplifier. The
RA2100b is a stereo 100W/channel RMS power amplifier in a standard 2 rack
space format. It is intended for professional audio and distributed musical applica-
tions. The unit features 100 Watts per channel RMS into four ohms, 85 Watts per
channel into eight ohms, and for the contractor - 70 Volts / eight ohms.
The unit also features MOSFET drivers in a voltage and current gain circuit, a
one-second input turn-on delay, and LED power output meters. The RA2100b will
drive 25 Volt speaker lines directly from each channel, or 70 Volt lines bridged.
INSPECTION
1. Unpack and inspect the RA2100b box and package.
If obvious physical damage is noticed, contact the carrier immediately to make a
damage claim. We suggest saving the shipping carton and packing materials for
safely transporting the unit in the future.
2. Please complete the Warranty Registration at www.rolls.com.
INSTALLATION
Connect the power cord to an AC power source, connect the input to the signal
source and to the RA2100b via the RCA or 1/4” input jacks. Speakers may be
connected by using the dual banana posts. Turn the
Volume controls fully counterclockwise (off), and turn on the power switch, the
power LED should light. With the program material running, slowly increase the
Volume controls until the desired level of sound is present. There is a one second
turn-on delay provided to prevent possible speaker damage in case all equipment
is on a signal power strip.
BRIDGING
To bridge the RA2100b, first ensure the power is off. Switch the Bridging switch to
the “Bridge” position. The Channel 1 Volume control will be the master volume,
Channel two Volume is inactive.
Connect the input to Channel 1 input, then connect the load (speakers) to the two
positive (red) banana jacks (CH1 + is + and CH2 + is now -).
Make no connections to the black posts.
FAULT PROTECTION
The fault protection in the RA2100b limits the current to the output stage in the
faulted channel and turns on the CLIP LED for that channel. This mode is entered
whenever the output stage is called upon for too much power, it may also be
fooled by impedances lower than four ohms - which may cause the output stage
to overheat and burn up the MOSFETs.
Since the RA2100b is convection cooled, the unit radiates heat from the rear
panel and , depending on the load demand, it may become very hot if drawn upon
heavily.
DRIVING 25 OR 70 VOLT LINES
The RA2100b will drive 25 or 70 Volt lines directly with no added transformers
when used the following way:
• Each channel will drive 25 volt lines directly.
• A single 70 volt line may be driven when the RA2100b is in Bridged mode. In
order to drive two 70 volt lines, two 8 ohms to 70 Volt conversion transformers will
be needed.
SCHEMATIC
1
ROLLS CORPORATION
5143 South Main Street
Salt Lake City, UT 84107
128-Jun-1999
Title RA200 POWER AMP BOARD
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RA200.SCH