The Amplifier shall have built-in circuitry to protect the
Amplifier from open circuit, short circuit, or mismatched
output loads, by using current-limiting, voltage-limiting,
temperature-sensing diodes, and thermal-sensing switches.
The automatic thermal-sensing switches and
temper-
ature-sensing diodes shall be mounted on the output tran-
sistor heat sinks to protect the Amplifier from overheating
due to short circuits, mismatched output loads, or high
ambient temperatures. The thermal switches shall auto-
matically shut off the ac power in the event of overheating
and shall automatically restore the ac power when the
Amplifier has reached a safe operating temperature. When
the Amplifier has thermally cycled off, a THERMAL OVER-
LOAD indicator shall light.
The INPUTS shall accept signals from high impedance
sources. The balanced bridging input shall be a profes-
sional three-pin audio connector. The unbalanced input
connectors shall be standard
%-inch phone jacks.
The Amplifier shall have an independent VOLUME Con-
trol and POWER ON-OFF Switch. The Amplifier shall be en-
closed in a metal, rack-mounting cabinet, with a
scuff-
resistant vinyl-covered front panel. The dimensions shall
be 178 mm x 483 mm
x
270 mm (7 inches in height,
19
inches in width, and 105h inches in depth). The weight
shall be no more than 12.23 kg (27 pounds).
The Amplifier shall have a maximum voltage gain of
27
k2 dB at
1
kHz,
and a nominal input sensitivity of
1.2
volts for 200 watts rms output power to a 4-ohm load.
The Amplifier hum and noise shall be at least 80 dB
below 200 watts rms output with a 4-ohm resistive load.
The Amplifier shall contain 4 silicon output transistors,
10 other silicon transistors, and
1
Zener diode.
Any Amplifier not meeting all of the above specifications
shall be deemed unacceptable under this specification.
The Amplifier shall be a Shure Model
SR105B.