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1947-48 Theatre Catalog, 6th Edition, Page 343 (329)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 343
Page 343


1947-48 Theatre Catalog, 6th Edition, Page 343

either a pre-amplifier or, in some cases, to an .extension cable for the wall type of amplifier.

In performance, the optics allow the recommended Academy of Motion Picture Arts and Sciences curve to be pros duced with a noise level, projector operating, of less than 60 db, below normal operating power level. A frequency response curve illustrating the overall performance of the sound head is given in Figure 11. This curve is of slit performance alone and illustrates the frequency response obtainable with the cylindrical reduction lens system.

PROJECTOR BASES

The projector base supplied as stand ard with the 12000 Series equipment is'

shown in Figure 12 and is available in either the table training or non-training types. It consist essentially of a welded frame to which front and rear mounting base castings are attached. The center of gravity and weight is so adjusted that a balance point for the completely assembled projector falls behind the table pivot bar and underneath the arc lamp. Adjustment of the projector as to azimuth is obtained by a hand wheel mounted inside the base frame and is accessible by removal of a side panel. Bases are locked in operating position by two hand wheels on either side of the base main frame, locking into the table apron, which extends downward in the mechanism frame housing, The table consists of a front and rear casting of adequate section and is available in both training and non-training types. The are, rectifier starting switch and carbon repository are mounted in the rear of the projector base.

All wiring is brought to a terminal box (Figure 13) located in the front of the base, which is accessible by the removal of its cover plate. A trouble light outlet receptacle is mounted directly below the terminal box. Plugs are mounted in the mechanism base, facilitating rapid disconnection of the projector head itself.

The front table casting is removable from the rear table by bolts and other front tables are supplied meeting various conditions of projector base usage. The base is four-point leveling and when leveled, is held to the projection booth floor by expansion bolts, and so forth, which are spotted through the leveling screws themselves.

The exciter lamp supply is mounted in the base itself and consists of a selenium rectifier unit rapidly replaceable with good regulation and low ripple content.

CHANGEOVERS

Changeovers supplied with the projector head are of the zipper type and can be operated manually from either side of the projector for emergency use in case of solenoid failure. Projector heads are Wired so that no master projector is required and straightforward conventional changeover wiring is used with the exciter lamps being utilized for the sound changeover, photocell outputs and pie amplifiers being in an operating condition at all times. Facilities are available in the base terminal box for the attachment of lioor foot switches in case that should be preferred over the press button available in the projector head.

1947-48 THEATRE CATALOG



FIGURE Hie-The sound optics is of a type utilizing a cylindrical reduction lens system with the photo-electric cell located inside the sound drum. This allows 1qu use at all of the illumination transmitted through the film and eliminates the necessity for condensers between the film and photo cell. A pre-tocus lamp is used as the light source is fixed in relation to the reduction lens system.

I00



IOOO 10000

FREQUENCY IN O.P.$.

FIGURE ll#A frequency response curve illustrating the over-all performance of the soundhead is given here, showing the; upper and lower limits of 0.00075-inch high scanning beam. The curve is of the slit performance alone and illustrates the trequency response (in decibels) over the range at 60 cycles to 10,000 cycles a second, obtainable with the cylindrical reduction lens system of the 12000 Series.

FIGURE lZeThe projector base is available in either the table training or non-training types. It consists essentially of a welded frame to which tront and rear castings are attached.



FIGURE 13am] wiring is brought to a terminal box in the front of the base, which is accessible by the removal of its cover plate. Plugs are mounted in the base {or easy disconnection.
1947-48 Theatre Catalog, 6th Edition, Page 343