Richardson's handbook of projection (1930)

Page scan 000232 from Richardson's handbook of projection

Record Details:

Title:
Richardson's handbook of projection
Date:
1930
Publisher:
New York : Chalmers Publishing Company
Volume:
Richardson's handbook of projection
Leaf #:
000232
Language:
English
Subjects:
Motion Pictures, Motion Picture Technology
Collection:
Books
Format:
Books
Contributor:
Media History Digital Library
Sponsor:
Media History Digital Library
Coordinator:
Media History Digital Library
Description:
Date Added:
August 01, 2024
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1156 HANDBOOK OF PROJECTION FOR eight dynamic speakers. The Type "B" (SPU) has two voltage amplifier units, one of which is reserve equipment, and four power amplifier units, all of which are used to operate sixteen loud-speakers. In case of trouble with the voltage amplifier unit it is possible to switch to the reserve, merely by throwing a series of three switches. This operation takes less than one-half minute. In case of trouble with a power amplifying unit, this particular unit is cut out and the show run on the remaining units. Each power amplifier and voltage amplifier unit is provided with its own controls and is operated independently of the others. All of these amplifiers use the standard RCA Radiotrons. Filament current for the voltage amplifier units, and for the photo-cell exciter lamps, is furnished by a storage battery. Each installation has two storage batteries, one for use while the other is being charged. All wiring from the projectors to the amplifiers, and from the amplifiers to the batteries and loud-speakers is in suitable conduit and concealed. For installations where the theatre does not have 110-volt, 60-cycle alternating current supply available, convertors or transformers for changing to such power are installed. Two convertors are supplied with Types "C" and "B" (SPU) equipment, one to be used as standby equipment. With the Type "D" equipment only one convertor is supplied. The equipments outlined above present certain advantages, as follows: 1. All controls necessary for running the show, changing projectors and controlling volume are located on the front wall of the projection room, directly in front of the projectionist and easily accessible.