Film-Tech Forum ARCHIVE: CP55 Can you set non sync to prologic?

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Posted by Cameron Glendinning (Member # 3516) on 07-26-2006, 09:12 PM:

Looking into ways of setting up video sound in one of our cinemas, at the moment it is outputing a left and right signal for non sync, is there a way to switch or link to get the centre and surrounds on?

Posted by Darryl Spicer (Member # 711) on 07-26-2006, 10:33 PM:

By removing the J2 jumper on the cat. 243 control logic board and placing it in it's jumper holder will give you surrounds in the non-sync. However, I do not know of a way to get full pro logic on that system. But, if you had another device that could decode the sources pro logic into four channels and feed the outbuts to the L,C,R,S on the auxilary inputs that would work.

Posted by Charles Greenlee (Member # 3856) on 07-27-2006, 02:16 AM:

I at one time was looking into a way to do it, using the input from the analog reader. Unfortunatly, I was forced to shelve the idea due to the lack of tehcnical information on both the tolerances and levels of the inputs, and the levels of the non-sync systems. I was going to start with a simple setup that would match the signals, so I could switch over to the non-sync, and away from the optical pre-amp outputs, manually at first. Then I was going to sit down and read on how the automation signals the processor to go into non-synch and SR optical modes, and set it up to where it switches the circuit automatically. Had a bloack diagram drawn out somewhere around here.

Posted by Louis Bornwasser (Member # 3063) on 07-27-2006, 09:11 AM:

I think the center channel is muted with a diode on the 241 or 243 board (the one with the matrix of diodes. If you can get surrounds, you are going through the matrix. Louis

Posted by Gordon McLeod (Member # 33) on 07-27-2006, 02:14 PM:

If you have the SRA5 adapter put a DPDT relay or switch on its output return to ther processor and feed the video in there and select 05
the level will be about 300mv at 50% which is close to most consumer DVD players

Posted by Brad Miller (Member # 2) on 07-27-2006, 03:01 PM:

A few years back I converted some CP55s to EX decoders by doing exactly this...but I can't for the life of me remember what I did, but it did involve some soldering of diodes on one of the cards.

Posted by Charles Greenlee (Member # 3856) on 07-27-2006, 09:03 PM:

Yeah, I was looking for a way to do it externally, without having to modify the processor itself. I decied that when I was trying out one of my CD's on the music system. I went in to the "big" house, which sports a nice system, and was disappointed to here it in 2 channel stereo and not surround.

I had figured the signal input for the analog optical on the processor probably acceptsd a lower level than that of the non-synch, meaning I'd have to attenuate it.

[ 07-27-2006, 11:53 PM: Message edited by: Charles Greenlee ]

Posted by Gordon McLeod (Member # 33) on 07-27-2006, 09:44 PM:

Charles your post makes no sense
If you go digging on this site most of the bus levels have been discussed

Posted by Charles Greenlee (Member # 3856) on 07-28-2006, 12:02 AM:

Sorry Gordon, made sense when I typed it. I can get scatterbrained at times. I edited it to make more sense, and removed the questions.

In regards to your research comment, I had. However, I was looking for the right thing, but with the wrong words. I typed using "input buss levels" and "output buss levels" and variations thereof, and found that it seems 300mV is common to all inputs, optical, nonsynch, mag, etc alike. In fact it seems to be the default for most processors as an output level. Would this be right?

If 300mV is common, that'd mean I would not need to attenuate the signal coming from the music. I'd simply need a set of trimpots to make sure the volume was at a decent listening level. Then that just leaves setting up something to receive the automation signal in order to have the "adaptor" switch between optical and music, rather than it being done on processor, since we are running the music through the optical input. (Basically, the processor would not leave the optical format when the movie ends, just switch at the adaptor.)

Posted by Cameron Glendinning (Member # 3516) on 07-28-2006, 01:47 AM:

Darryl, Charles, Louis, Gordon & Brad, Thankyou all so much, I should have mentioned that I have both the SRA5 & a DA20, My need for this modification is the temperary install of a Digital Server for a season of 49Up (stereo out british TV doco). I am not fond of Lt Rt in our wide cinemas especially for a 3 hour show! Do you think that the server would output a signal of 300mv?
I was sure that many years ago I had worked with a CP55 that would decode non sync this way, although at the start of the day would only be left, right & surrounds, once selecting film and then back to nonsync the centre would work? never made sence to me before reading this thread.
I currently put DVD 5.1 in through the D conector in the back of the DA20 and tape down the Digital button (demand is still rare)I have also put a consumer pro logic processer in this way for a once only SP beta show (we dont own it).

Posted by Michael Schaffer (Member # 1204) on 07-28-2006, 04:30 AM:

Probably the easiest, cheapest, and unmessiest solution for you would be to use a consumer ProLogic receiver and simply hook up it's outputs to the CP55's external input. Disconnect the audio connection coming from the DA20 and switch it off (otherwise, you might be punished by low levels and hum). Then you should be able to manually select the format without taping down the button. Find the level carefully be setting the fader to 7 and slowly turning up the fader of the receiver.

Posted by Charles Greenlee (Member # 3856) on 07-28-2006, 08:50 AM:

Good point Michael. Besides, in scanning the install manuals, I noticed that the CP55 and CP65, at least, have their own optical pre-amp built right in. Which means the optical input is running straight from the cells, and may not be 300mV. I'm still checking on that.
At my current theatre we have CP55s and CP65s, so my idea for an adaptor wouldn't quite work the same. Nor is it necissary since on the logic board, you can set a jumper to include surround sound logic on non-synch. My old theatres had an external optical pre-amp, built into the lamphouse, and no option like the jumper, which is why I was interested in the idea. And I still may do something with it, its just not as high of priority.

Posted by Gordon McLeod (Member # 33) on 07-28-2006, 10:55 AM:

The Cp65 can be programed to route the Non Sync throught the 4:2:4 matrix mode by selecting the suitcase jumper
A word of caution is that the other Nonsync surround jumper needs to be removed
The CP55 the only way I have done it is switching the input from the SRA5 since it is at the input of the matrix
300mv is the most common buss level but not the only one CP100 had different levels SMart and USL had diffrent internal bus levels
Because consumer DVD players are typically 707mv at 0db they don't have a big issue when connected to the 300mv 50% buss
A pair of trim pots is a good idea to trim the level and also to ensure that LT and RT are matched to make the matrix steer correctly

Posted by Charles Greenlee (Member # 3856) on 07-29-2006, 01:17 PM:

quote: Gordon McLeod
A pair of trim pots is a good idea to trim the level and also to ensure that LT and RT are matched to make the matrix steer correctly

My logic exactly. What is a suitcase jumper? And BOTH the CP55 and CP65 have a control logic boards, and a surround disble jumper on them, that appears to be the same almost. I removed the jumpers and placed them on their "holding" pins. So according to the manual, I should be in surround, but still noting. I think the Distribution center's not sending to the houses in stereo. I'll have to check it out later.

quote: Gordon McLeod
The CP55 the only way I have done it is switching the input from the SRA5 since it is at the input of the matrix

Clarify, I'm not sure what you mean. Is it necissary because somehow the jumper doesn't work?

Posted by Cameron Glendinning (Member # 3516) on 08-01-2006, 05:27 AM:

Gordon is letting us know the easiest way to wire and get the full left centre right and surrounds to work, I have also heard that it is easier to modify the CP65 for non sync than the CP55.

Once again thankyou all, I have plenty of options now [Smile]

Posted by Gordon McLeod (Member # 33) on 08-01-2006, 12:53 PM:

On the cp55 and cp65 the suitcase jumper for surround feeds a sum to the surround speakers
on the cp65 on sets it nonsysnc in the 4:2:4 mode only
Using the SRA5 path is the only gracefull way on the CP55

Posted by Gunter Oehme (Member # 499) on 08-01-2006, 06:02 PM:

Actually removing the NS Surr jumper on Cat 243 feeds the surround decoded by Cat 150 from the NS input to the surround output as desired. However the NS L and R feeds directly to the L and R output without decoding.

To get a full prologic decode (without sub woofer) a rather simple modification on Cat 243 is required. Just remove INC D84 diode and add another diode as shown:

This modification applies if no SRA5 is installed.

Posted by Charles Greenlee (Member # 3856) on 08-01-2006, 06:57 PM:

As much as I'd enjoy taking a crack at modifying the Processors at work, I will refain from doing so. They aren't mine, I'm not that far trained, though I'm confident I could do it, but I doubt I'd get permission from Regal to make the modification. Remember, right now I'm new to them, so they'd assume I don't know much, 'till I get my Certifications. [Wink]

Besides, while I'd like to have it, it isn't a necissary thing. But if anyone else tries it, let me know how it turns out, may fuel my plea later to make the mod.