Film-Tech Forum ARCHIVE: CP200 & SR /w Accessory Unit?

This is topic CP200 & SR /w Accessory Unit? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Chris Trainor (Member # 9) on 09-10-2004, 12:44 AM:

Hi all,

Got a question on using the Accessory unit of a CP200 to provide SR NR decode. Essentially since I don't have any magnetic capabilities (nor do I think I will in the future) I'd like to use the Le/Re NR slots on the accessory unit for Optical SR... kinda like using it as a glorified SRA5. I was thinking of just rerouting the NR lines between JM5 and JM32 to the Lt/Rt ins and out on the processor unit and wiring up the Special 1 card as described in the SRA5 guide.

My question I guess is: is this the 'right' way to do it? Is there a better way?

Thanks,
--Chris

Posted by Tony Bandiera Jr (Member # 2365) on 09-10-2004, 01:28 AM:

Chris:

Me thinks you're going thru a lot to do a simple task. [Smile]

I just plug the CAT 280T's into the left and right NR slots in the processor unit, and run with format 04 (you can build a duplicate format 05 line to be really correct about it.)

Or are you in a situation where you need to rapidly switch between A and SR type NRs?

I would imagine your method would be possible and should work well. IMHO, I wouldn't spend the time on it though.

Posted by Steve Guttag (Member # 268) on 09-10-2004, 06:28 AM:

The problem with either method described above is that you have not corrected for the 3-dB difference between SR films and A films. Without a 3-dB boost so SR films, if you have say a Dolby DA-20, your analog backup track will play 3-dB lower than Digital.

Ultimately, anything is possible with a CP-200 but you may have to work at it.

Steve

Posted by Chris Trainor (Member # 9) on 09-10-2004, 12:30 PM:

Tony: That's what I'm currently doing, but I do need a way to easilly swap between A and SR.

Steve: damn, forgot about the 3db difference. [Frown]

Was the boost a function of the SRA5? Is there some magic you can do internal to the 200 to give it a kick? Only thing I can think of is using say a 117 to bump up the signal, but for some reason I don't think that's a good idea to use one before a NR module...

thanks,
--Chris

Posted by William T. Parr (Member # 677) on 09-11-2004, 09:26 PM:

Hey Chris If you find you do not need the Accessory unit please drop me a line. I work with a local none profit rep. house that has a basic CP200 that needs an Accessory kit as they do tons of 70mm movies a year.

Posted by Chris Trainor (Member # 9) on 09-11-2004, 10:24 PM:

I just bought it, not going to part with it quite yet. [Smile]

--Chris

Posted by Rich Ferrando (Member # 2056) on 09-11-2004, 11:08 PM:

Along these same lines, about three months ago we got the CAT 280T cards for our CP200, and I installed them in place of the Left and Right CAT 22's that we had, and what I was left with was... Mono. Even when I put the CAT 22's back in, it remained mono in Format 04, and still is to this day.

However, I'm not entirely sure as to whether or not it was Mono before I messed with it. See, in February the company engineer came out and rewired the CP200 to work with our new DA-20. Prior to this install, I know that we had all channels working in Format 04, but afterward, everything we got was SRD (and dropouts are rare for us), so I never got a chance to hear analog after the install. In May, when we got the "Life of Brian" reissue, which was SR, was when I decided to swap-out the cards, and it wasn't until after that swap that I noticed we were Mono-only in Analog.

We tested the CAT 280T's in a CP55 at our sister theatre, and they seemed to function great. So I don't know if maybe I screwed something up when I swapped out the cards, or if something got bypassed when the CP200 was rewired for digital.

Any ideas?

Posted by Brad Miller (Member # 2) on 09-12-2004, 12:05 AM:

It would help if you would mention what format you are trying to play the analog sound in. Format 10? Format 4? Format 5?

Posted by Chris Trainor (Member # 9) on 09-12-2004, 01:55 AM:

Brad, he mentioned format 4.

As for the problems, I wonder if the 'tech' stole a few diodes from another format to get the SRD format to work. The NR cards don't do anything other then decode LtRt from the optical preamp (unless of course they are in mag mode). They have no 'say' in what goes thru the matrix for Dolby Stereo decoding.

Do you know what kind of matrix board you have in there? If it's one of the newer ones you should have little blinkey lights when it's active and what channels are active. If the format card was for some reason screwed up and makes all optical mono, then on the 150 matrix card you should generally get no lights at all during playback... tho maybe just center, but as far as I can remember when academy mono is select (format 01) nothing lights up on the matrix. If that's the case it's a format card issue I would presume.

--Chris

Posted by Darren Briggs (Member # 1071) on 09-12-2004, 07:43 AM:

What are the system status lights saying on the CP200 control unit? do they say
Optical
Stereo
NR in
Mono Surround
Bass Extension

Posted by Rich Ferrando (Member # 2056) on 09-14-2004, 07:40 PM:

Sorry for the delay - I was off all weekend.

Yes, it is Format 04 - and the following status lights are lit:
- Optical
- Mono
- NR Out
- Mono Surround
- Bass Extension

On the CAT 150, only the Center-channel light is "blinkey."

Posted by Chris Trainor (Member # 9) on 09-14-2004, 10:22 PM:

Well, the 'mono' and 'NR Out' are not what Format 04 is supposed to be... it should be 'Stereo' and 'NR In'. Format 05 would be 'NR Out' since it is passing to the SR cards for NR. Something funky is going on. You might want to check the format cards against the manual to see if the diodes have been moved around for Format 04.

--Chris

Posted by Chris Trainor (Member # 9) on 09-15-2004, 01:22 AM:

Steve (or anyone else who knows..):

So I've been going thru my Accessory box trying to find a somewhat 'simple' solution to using it to hold SR cards effectively. After looking at the backplane diagram I see that the Aux 1/2 inputs will route from a 117 down to the NR modules and then back out the Aux 1/2 outputs. So I could in theory run it thru that way, and use the 117 to give me a boost on the way. My question I guess is, do the 280's accept input from the 'aux' pins? I don't have a manual on the 280 to tell for sure. Do they actually do any NR decoding off those pins? On the wireing sheet it's pin11 in and 12 out on the Cat 22.

Thanks,
-Chris