
CONNECTION:
DESCRIPTION:
To operate the HR251, properly connect
cables from a source to the RCA or XLR
channel inputs of the HR251. Connect
the HR251 outputs to speakers 4 Ohms
or higher impedance. Adjust the channel
level controls for the desired volume.
NOTE: THIS MANUAL ASSUMES THE
USER HAS A WORKING KNOWLEDGE
OF AUDIO ELECTRONICS, BALANCED
AND UNBALANCED CONNECTIONS,
AND PROPER SIGNAL LEVEL SETTING.
The HR251 is a dual channel, 50 watt,
power amplier designed for audio and
visual professional applications. An
FR4(V94-0) rated glass epoxy circuit
board and powder coated steel chassis,
make the HR251 a product that will last.
Inputs are stereo RCA and XLR at line
level. The HR251 has Plugable Phoenix
connectors for outputs.
What's in the box?
1 - Made in USA HR251
1 - 24V power supply PN KSU100
1 - This owners manual
Rolls Corporation
Salt Lake City, UT
9-21
HR251 50 + 50 watt
Power Amplier
SPECIFICATIONS:
Input Impedance: 10K Ohms RCA
10K Ohms XLR
Power Output: 50 Watts X 2 (4 Ohms)
Voltage Gain: 30 dB
Maximum Supply Voltage: 24 VDC
THD: .05% typical
EIN: 3 mV
Eciency: 87%
Input Sensitivity: 28 mV
Bandwidth: 20Hz - 25 kHz +/- 3dB
Size: 6.5" x 4" x 1.5"
Connection guide

WARNING: THE MINIMUM SPEAKER IMPEDANCE IS 4 OHMS EACH.
IF YOU CONNECT AND USE THE HR251 WITH A LOWER SPEAKER IMPEDANCE THAN 4
OHMS YOU WILL DAMAGE THE HR251 AND POSSIBLY OTHER EQUIPMENT THAT IS CONNECTED TO THE OUTPUTS.
Stereo XLR
DC jack for
connection to
the included
Rolls KS100DU
power supply
Line level
inputs.
RCA Stereo inputs.
Outputs. Plugable Phoenix
connector for connection to
speakers.
24V 4A
KS100DU
MADE IN USA
www.rolls.com
2
XLR BALANCED INPUTS RCA
1
HR251
2 Channel 50 + 50 Power Amp
OUTPUT
CH.2
2
1
CH.1
-+-
CH.1
+
CH.2
HR251
Power switch and LED
power indicator.
Level control will
adjust channel level
outputs.