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ANNOUNCING
THE NEW
P-R-L 7-A SOUND SYSTEM
FOR COMPLETE A.C. OPERATION OF SOUND-ON-FILM APPARATUS
A COMPLETE AMPLIFICATION AND POWER SUPPLY SYSTEM
FOR TWO
SOUND HEADS
WITH FADER AND ALL CONTROLS BUILT IN
NO BATTERIES OR ADDITIONAL APPARATUS
NECESSARY
CAN BE USED WITH ALL TYPES
OF P. E. CELLS
CAN BE INSTALLED BY ANY ELECTRICIAN IN ONE HOUR
PRICE *235-00
THE PRL 7-A Sound System has been designed to meet the requirements of theatres having a capacity up to 750 seats and represents the entire electrical apparatus necessary for sound-on-film reproduction from the output of the photo-electric cells to the input of the speakers. It contains a three stage high-gain amplifier especially designed for sound-on-film recordings and in addition to supplying the current for the P.E. cells it provides direct current for the exciter lamps.
The PRL 7-A Sound System is complete in every detail and no additional apparatus other than the sound-heads and speakers is required for a complete installation. No batteries or expensive filters are used and it will supply full current to both exciter lamps simultaneously which permits adjustment of one sound-head while other is in operation.
The control panel of the PRL 7-A Sound System is built in the top of the cabinet and contains all apparatus necessary to maintain a constant and accurate check on the equipment during operation. Incorporated in this panel are two calibrated potentiometers and switches for controlling the current to the P.E. cells, two switches, two heavy-duty rheostats and two Weston D.C. ammeters for separate control of exciter lamps. The fader-volume control consists of wire-wound resistance units and a Weston rotary switch. Each side is calibrated to read in decibels according to standard Western Electric volume levels.
The PRL 7-A Sound System being completely selfcontained is small enough to permit installation between the projectors and as all connections are brought in to two marked terminal strips it may be installed by any electrician in one hour and as all parts are standard and interchangeable it may be readily serviced by any competent radio service man.
FOR FURTHER INFORMATION WRITE OR WIRE
PACIFIC RESEARCH LABORATORIES
1907 FOURTH AVE.
LOS ANGELES, CALIF.