2-10
2.5
Connections to Dolby Cinema Processors
The DA20 may be connected to any of five Dolby Cinema Processors: the CP45, CP55,
CP65, CP200, or CP500. Two types of electrical connections must be made between the
DA20 and the cinema processor:
1. Audio through DA20 rear panel connectors J7 and J8.
2. Cinema processor format sensing and control through DA20 rear panel connector J6.
The specifics of connection to these connectors are described for each Cinema Processor
type.
2.5.1 Installation of DA20 with CP55
Refer to the CP55 wiring diagram fold-out (Figure 2.9).
To playback Dolby SR and Dolby Digital films correctly it is highly recommended that
you upgrade the CP55 for Dolby SR. The Dolby Model SRA5 adapter is no longer
available, however you should arrange to acquire a Cat. No. 222SR/A card. This card
replaces the existing Cat. No. 222 noise reduction card and provides two channels of
Dolby SR processing and Dolby A-type noise-reduction.
2.5.1.1
Revised SRA5 installation procedure
(If your theatre is so equipped)
The following section is for an existing installation with Model SRA5 available. If you do
not have an SRA5 installed, skip this section and go to Cat. No.441 Installation, Section
2.5.1.2.
The original SRA5 installation procedure was developed in order to avoid soldering to
the backplane of the CP55. Unfortunately, this method makes use of the AUX format,
which will be needed for use by the DA20. Therefore, if your theater is equipped with an
SRA5 installed in the original way, you will need to revise the installation before
proceeding further. (If you are reconnecting an SRA5 that was previously connected
using the original method, make sure to remove the wire connecting the OBE terminal on
TB2 of the SRA5 to J18 on the CP55. Unplug the D-Sub connector from CP55 J18, cut the
wire at the SRA5 end and discard this wire.)
This procedure describes an alternative method of interfacing the Dolby SRA5 to a CP55
cinema processor. An advantage of this method is that the SRA5 signal output is
returned to the CP55 via the Dolby tone inputs of the Cat.No.222 card instead of using
the non-sync inputs as in the standard method. As a result, the non-sync source can
remain connected to the CP55 non-sync terminals. Using the Dolby tone input also
provides a fixed input level, so no signal calibration needs to be performed.
This method relocates the Dolby Stereo SR format to “03,” making the “AUX” signal
input and selector button available for use in selecting the Dolby Digital format.
The only drawback to this method is that the Dolby tone inputs are only accessible by
soldering directly to the Cat.No.222 edge connector. This is a simple procedure, but one
that must be done carefully to avoid splashes that can cause short circuits.
