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1945 Theatre Catalog, 4th Edition, Page 342 (318)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 342
Page 342

1945 Theatre Catalog, 4th Edition, Page 342

The pre-focused exciter lamp of new design has a short sturdily supported filament minimizing vibration. The ex citer lamp bracket is easily removable and designed to permit vertical and latera1 adjustments for exact positioning of filament. The exciter lamp compartment is well ventilated and careful shielding prevents any stray light from entering film compartment.

The highly efficient oil-proof optical system is designed for protection against soiling.

The photo-electric cell vertical mounting eliminates microphonic noise, and is completely out of way when threading film. It is easily accessible for cleaning or replacement, less susceptible to static disturbances from film, gears, or take-up belt and well shielded against stray light. It is impossible for oil to reach and saturate connecting wires and socket which are well protected and shielded in photo-cell arm casting.

Lateral film guide and pressure roller equipped with trigger control for easy operation.

The drive motor, cradle suspended, is an over-size, one-quarter horsepower split-phase induction motor, with ballbearing-mounted rotor, insures constant speed with variation of less than 0.5 per cent with voltages from 105 to 125

volts. Flywheel of proper design insures correct starting speed.

Film drive sprockets, sound and holdback, are included. All shafts of drive mechanism rotate on dust-proof ball bearings.

The drive mechanism is one assembly, easily removable as a single unit by removing four screws.

A sight oil gauge gives immediate and positive visual indication of oil level in reservoir, insuring proper lubrication of sound mechanism if oil level is maintained.

Sound-head design insures accurate alignment of projector drive gears and easy installation or removal of projector mechanism.

The cabinet of the volume-control amplifier. neat and compact, permits mounting on front wall of projection room to avoid vibration. It may be partially recessed in wall for concealment of wiring.

Volume control for system is a special design, de-tented step-by-step potentiometer having 19 2-db. steps. .

Two-stage resistance coupled voltage amplifier employing 6J7 tubes has a 46 db. gain. Normal operation is at 26 db. The metal Type 6J7 tubes were selected for inherent shielding, uniformity and freedom of microphonic tendencies.

Electronic sound change-over coma


prises a three-way switching arrangement, one at each projector station, to control bias of second stage of volume control amplifier. This method of changeover control is instantaneous and noiseless since it avoids the necessity of breaking the signal circuit. Switching may be made at either projector. The exciter lamp circuit is simultaneously transferred in the change-over operation.

Photo-electric cell balances equalize the signal input to the power amplifier.

Dual amplifier units with single shaft, operating both volume controls in unison, can be accommodated. This provides for emergency operation or dual track reproduction.

Post-equalization. Design provides for incorporation of post-equalization facilities to properly reproduce special pres equalized recordings at such time as they may be generally released.

Co-axial cable of special low-capacity couples photo-electric cell output to volume control amplifier. Low capacity

shielded cable connects volume control

amplifler to power amplifier

In the main amplifier equipment, the power transformer mounted on each amplifier chassis is oversize to render continuous service on 50 or 60 cycles and tapped to compensate for various line voltages of 105, 115, and 125 volts.

Amplifier frequency characteristics. Warping adjustments permit variations in the low frequency and high frequency response characteristics, to match various loudspeaker characteristics and equalize for theatre acoustic conditions.

Loudspeaker network, with 400 cycle cross-over couples amplifier output to the twoeway loudspeaker system. Special design features, careful selection of capacitor, resistors, and other parts afford stability of operation under all conditions.

Loudspeaker network control panel incorporates switches for speaker testing and emergenCy operation on low frequency speakers only.

Amplifier switching facilities are provided to permit isolation of an inoperative amplifier from the Signal circuit without disconnecting from power supply.

Compact, sturdy construction throughout minimizes space, simplifies installation, and reduces maintenance cost. All parts on special mountings easily removable to facilitate servicing.

Genuine two-way loudspeaker system supplied with all Simplex Four Star sound equipments to assure highest quality reproduced sound and uniform distribution, covering every seat in theatre, without distortion due to overload.

High-frequency loudspeaker has a genuine multi-cellular exponential horn. The low-frequency has folded exponential horns of wood construction throughout. Driving units are of high power-handling capacity and efficiency.

The design of the monitor loudspeaker Type LU-100 is a definite step toward extension of the frequency response over that generally found in monitor speakers.

Monitor amplifier type AM-107 provides power to drive the monitor loudspeaker.

Exciter lamp operation on alternating current is possible in the event of failure in the rectifier system regularly supplying direct current.


1945 Theatre Catalog, 4th Edition, Page 342