Bogen BT 35 A Operating Manual

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V BOGEN

MODEL BT35A

TRANSISTOR MOBILE
~11) WATT P.:\. AMPLIFIER

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V INSTAllATION AND OPERATING MANUAl

READ THOROUGHLY BEFORE OPERATING EQUIPMENT

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GENERAL DESCRIPTION

The model BT35A represents the latest design in com-
pact high output amplifiers. This amplifier is intended for use
in mobile and portable public address work. Separate inputs
and individual gain controls are provided for a low impedance
microphone, and for high level auxiliary equipment (such as a
tuner. tape recorder, and crystal or ceramic phono player). A
function selector awitchpermits selection of the input source.

The Bogen BTSSA incorporates a radio input circuit
so that the output (speaker voice coil) of a two-way radio
(any radio for that matter) may be connected directly to
the amplifier. This enables the two-way radio transmission to
be heard outside the vehicle and at considerable distances.
Hence a policeman. fireman or director of Civil Defense may
leave his vehicle without fear of missing a vital message
being transmitted over the two-way radio. The possible ap-
plications are varied (e.g. the amplifier can be used to dis-
tribute music at political rallies, etc.). The BISSA is excel-
lent for such applications as police, fire department, civil de-
fense. marine, military or general commercial use.

The BTSSA is instantly ready for use since it employs
transistors and requires no warm-up time. Hum is non-exist-
ant with this type of transistorized amplifier. A protective
circuit and fuse provide absolute protection of the unit from
inadvertent reversal of battery connections or the shorting of
inputs or outputs to the chassis. The amplifier will operate

OUTPUT POWER: 40 watts; peak power 55 watts.

RESPONSE: thimized for maximum intelligibility
150 Hz to 15 kHz, +3db.

GAINI Microphone input llOdb.
Radio-Aux. input 90db.

DISTORTION: Less than 107. at full output.

NOISE (Below Rated Output): Microphone ~90db.
Radio - Aux. -95db.

SENSITIVITYI Microphone 1 millivolt.
Radio and Aux. 0.40 volt.

FULL RATED POWER TEMPERATURE RANGEr -22
to + 149 degrees Fahrenheit.

SPECIFICATIONS

from the battery of any motor vehicle regardless of grounding
polarity.

The unit can be operated from any 12-15 volt DC source.
The amplifier supplies a full 40 watts output at a maximum
power supply current drain of 4 amperes. The quiescent cur-
rent drain is 0.5 amperes. The frequency response is opti-
mized (150 to 15,000 cps) to provide maximum intelligibility.
The speaker used with the unit may have an impedance of 4,
8, or 16 ohms and should be capable of handling a minimum
of 40 watts. '

The BT35A is exceptionally temperature stable. Oper-
ation will not be affected by extreme climatic conditions
from -3o°c (42°F) to 65°C (149°F). The amplifier is com-
pact, lightweight and portable and very rugged in construc<
tion. The unit is splash proof if mounted with the control
panel tilted upward. This enables the unit to be used in
areas subjected to rain or spray. A gasket seals the chassis
in the cabinet.

The BT35A incorporates a new concept in mounting and
is designed for quick installation. The unit has a U" type
adjustable bracket and thumbscrews which permit mounting
on any convenient surface (vehicle dashboard, vehicle frame.
etc.). The adjustable bracket permits positioning of the unit
to any desired angle. The unit weighs only 6 lbs and is com-
pact in size measuring 8" x 6-'/i" x 3".

WARM UP TIMEr Instantaneous.

CONTROLS! input Selector/Power Switch, Microphone
Volume, Radio-Aux. Volume.

INPUTS! (3) Microphone (50-500 ohms, 200 ohms nolrp
inal), Radio, Auxiliary.

OUTPUT IMPEDANCE: 4, 8 or 16 ohms.

CURRENT DRAIN: 500 ma quiescent, 4.4 amps at full
rated output.

WEIGHTt 6 lbs. (8 lbs. shipping weight).

DIMENSIONS: 8"w x 6/Ad x 3"h.

INSTALLATION

MOUNTING

The BTBSA may be mounted in any position and on prac-
tically any surface. A typical installation onto the underside
of an auto dashboard is illustrated in figure 1. The unit may

also be mounted on the frame of the vehicle, or to any con-
venient surface.
To attach the U" bracket to the BT3SA case use the

thumbscrews provided. Before tiditening thumbscrews,adjust
the BT35A to desired anale.