Operating instructions

C-1
APPENDIX C
CP45 MODULE DESCRIPTIONS
Cat. No. 510/514 Input/Output Card
The Cat. No. 510 is the input and output part of the CP45. It has two
stereo inputs for optical soundtracks, one mono microphone input, and
six outputs for the front screen speakers. The card is normally fitted
with a Cat. No. 514 optical preamplifier card which converts the solar
cell signals from the projectors into voltages which are handled by the
Cat. No. 510.
This card also contains the power amplifier output stages for the front
screen speaker channels.
Cat. No. 511 Main Board
The Cat. No. 511 main board carries all the circuitry for decoding Dolby
A-Type and SR encoded film soundtracks. The unit also carries a power
supply circuit which converts the low voltage AC supply from the
external transformer into the various voltages used in the unit.
The board has all the logic switching for the various modes and carries
the electronic volume control circuits for most of the outputs.
There is also a pair of inputs which can be connected video projectors
etc. and which feed the Dolby decoder. This input can also be used for
background and intermission music.
The board also carries the driver circuitry for the Cat. No. 222 or Cat.
No. 222A/SR modules and the audio delay circuit for the surround
channel.
If the unit is to be used with a large amount of mono material, there is
a circuit which generates a pseudo-stereo output which tends to liven
up such sources and enhance the reproduction of music.
Cat. No. 512 Equalization Board
The Cat. No. 512 board carries all the house equalizer controls for
adjusting the acoustic response of the theater. There are seven 2/3
octave bands which cover the frequencies which cause most difficulty in
loudspeaker systems.