Film-Tech Forum ARCHIVE: Dolby CP500 for subrun?

This is topic Dolby CP500 for subrun? in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Ronda Fitzsimmons (Member # 1418) on 05-03-2019, 09:43 PM:

I just bought a bunch of working CP 500's at an auction. Can I use them for second hand equipment for a subrun theatre? What would it need to work?

Posted by Stephan Shelley (Member # 8587) on 05-03-2019, 11:10 PM:

First you should delete the duplicate thread.

Are you planning on using these for digital cinema? If so you will need a six channel Digital to Analog converter as there is no provision for a digital input natively. While they can do if properly equipped Dolby SRD Digital from film that is actually a video signal from the SRD reader.

If you plan is to run film then just hook up the optical and SRD if so equipped and do your A chain. Connect the output to your amps and speaker and do your B chain. You will have to do that last part for D cinema as well.

Posted by Ioannis Syrogiannis (Member # 3235) on 05-04-2019, 01:35 AM:

In addition to the Digital to Analog converter, you'll have to be sure that the CP500s have the Cat.685 (optional) board installed.

Posted by Marcel Birgelen (Member # 6801) on 05-04-2019, 04:27 AM:

In my humble opinion, the CP-500 is a particular bad choice for digital cinema, especially for new setups.

You need an external DAC and the Cat 685. So, you're essentially going from Digital to Analog to Digital back to Analog. Also, you can't do proper 7.1.

Posted by Dave Macaulay (Member # 813) on 05-04-2019, 07:50 AM:

They will work, if you have a d-a and cat685 for each screen.
Cost those out if you don't have them, though. Probably a Dolby CP750 or USL JSD-60 will be comparably priced and considerably superior.
Tuning a room with a 500 via the panel is tedious compared to a new processor via its network gui. The CP500 LCD panels go bad and are not made now. No parts or service from Dolby. It was a beaut when released but is now obsolete.
If you do want to use them, remove the analog preamp board and all the circuit boards for SR-D... all useless for digital cinema and just stressing the power supply if left in. Then look at what's left - a nearly empty box with dodgy display panel, clunky interface, no warranty, parts unavailable...

Posted by Sam D. Chavez (Member # 1841) on 05-04-2019, 10:32 AM:

Agree with all the critics of the 500. The main problem area is the LCD panel which essentially junks the unit.

I carry parts for the CP500, used but reliable if you are determined to use it. I would assume at least a couple of the 500's you purchased have good front panels. The Cat. 685 is the next issue and take a look and see if you have any among them.

I only mention this as you already own the 500's. Otherwise I would not bother.

Posted by Ronda Fitzsimmons (Member # 1418) on 05-04-2019, 08:49 PM:

They do have the Cat 685 cards in them. I didn't pay much for them, and I have enough to do a full backup. What's the DAC you mentioned please?

Posted by Stephan Shelley (Member # 8587) on 05-04-2019, 09:01 PM:

I like the Dolby DMA 8+. The USL ECI 6 will also work. They both offer SPIDF and Tosslink connections as well as a 6 channel (8 in the case of the DMA 8+) AES and a 6 or 8 depending analog pass through. Not a fan of the Doremi DtoA.

Posted by Ioannis Syrogiannis (Member # 3235) on 05-05-2019, 12:33 AM:

It's the Digital to Analog Converter (DAC) that converts the AES/EBU signal coming from the server to analog, so that CP500 or other audio processors that don't support the function to be used for -say- digital cinema.
There are quite a few companies that provide or have provided such DACs. From the top of my mind:
Dolby DMA8+, Dolby/Doremi AUD-D2A, USL DAX-602 or 802, Proyecson P-DAC11, XDC CineStore Dian or Audi etc.
Unfortunately, some of them are now obsolete, not due to their capabilities, but due to their unavailability, their reaching their end-of-life if you prefer.
And that is understandable, at a time when audio processors that do support AES/EBU input started to get "retired".