Figure 7-27.--Block diagram of an amplifier.

cooler operating temperatures than would otherwise be

channel. A portable microphone jack is also provided.

possible. Figure 7-27 is a blockdiagram of an amplifier.

This jack can be used for local testing of the system or

for talking.

Switches, Timing Controls, and Indicators

Three toggle switches located on the front of the

The microphone control station inputs to the am-

control panel provide power to the amplifiers and the

plifiers are controlled by five 2-position toggle switches

relays.

located on the front of the control panel. In the ON

position, the microphone control stations are connected

A power available lamp and six blown-fuse indica-

to the amplifiers, and in the OFF position, they are

tors are also mounted on the front of the control panel.

disconnected.

ADDITIONAL SOUND EQUIPMENT

The outputs of the amplifiers are individually

Additional sound equipment used with the system

connected to the loudspeaker groups by five 3-position

consists of (1) microphone control stations and (2)

toggle switches located on the front of the control panel.

loudspeakers.

In the up position, the loudspeaker groups are connected

to channel A; and in the down position, they are

Microphone Control Stations

connected to channel B. Under normal operating

The microphone control stations located in the sonar

conditions, the switches should be positioned so that the

control room consist of both microphones and foot-

loudspeaker load is evenly divided between both

operated switches. A portable microphone and an

amplifier channels. When the switches are in the center

associated jackbox is provided for the sonar control area

position, the loudspeaker groups are disconnected from

supervisor, and a flexible microphone and foot-operated

the amplifier outputs. Separate connections provide for

switch is provided for each sonar operator's position.

local speakers located adjacent to the associated

The flexible microphones and foot-operated switches

microphone control stations, and muting features are

are wired in parallel to permit hands-free operation by

accomplished in the control rack.

the operators. The microphone inputs from the

An output test meter and two toggle switches,

operators' positions connect to the control panel relay

designated CHAN A and CHAN B, are provided on the

assembly in such a manner that only one microphone is

control panel for testing the output of each amplifier

connected to the amplifier input at a given time. This

Figure 7-27.--Block diagram of an amplifier.

7-26