Film-Tech Forum ARCHIVE: dolby CP65 question, new to this

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Posted by Bradley Johnson (Member # 5154) on 02-26-2009, 07:18 PM:

Sorry guys,,,,,I am a newbie in this field so go easy on me.

I live in a very small town in Wa state and we are lucky enough to have a very old but great cinema here. It recently was sold by the original owners (it was built in 1952). The new owner came to me to help upgrade the sound system from the original mono amp and single speaker cabinet. I am a live audio engineer by trade and was the only one around with any audio related experience. The cinema is on a very slim budget and I have donated my time. I have completely installed a left center right setup with sub and surround speakers. At the moment we are still using the original setup,,,my question is based on the Dolby CP65. I bought one on line and noticed that it did not come with the cat 350 cards. Will it still function? Should I be looking for a pair of said cards and if so, is there a modification that needs to be done, or can I just put them in the slots? The unit is not marked as a 65A. One other question is on the projector end of things. The readers are Kelmars and have no other label or id that I can find. My question here is being that the original system was mono, will these need to be upgraded?

Thanks!

Posted by Gordon McLeod (Member # 33) on 02-26-2009, 08:07 PM:

The readers need to be changed to red light so a reverse scan is a must recomend BACP or the CE ones
What noise reduction card is installed
If there is a catt222 then the unit will run just fine in a type mode
if it is a cat 222SR/A then it is ready to go for A and SR

Posted by Bradley Johnson (Member # 5154) on 02-26-2009, 08:10 PM:

It has a cat 222SR/A.

Posted by Mark Gulbrandsen (Member # 72) on 02-26-2009, 09:59 PM:

The CP-65's that have the CAT 350's are definately the preferable ones to have though. The 222 SR/A is not really true SR by any means. It's more of an emulator like Smart's cards were but it is better then the Smart cards.

Mark

Posted by Bradley Johnson (Member # 5154) on 02-26-2009, 10:36 PM:

Is it safe to say that if you have a CP65 with the 222 SR/A card and no 350 cards, that you are stuck with it as is? Is it possible to put the cat-350 cards into the unit I have?

Thanks!

Brad

Posted by Scott Norwood (Member # 30) on 02-26-2009, 10:56 PM:

Yes, you can add the cat. 350s (or cat. 300s) and it will use those for SR and the 222 SR/A for A decoding. They show up on Ebay all the time, usually as part of a 363 noise-reduction unit. You can throw away (or re-sell) the 363 frame and use the cards in the CP65. Unless you are running 70mm magnetic, either the cat. 300s or 350s will work fine.

It's a worthwhile upgrade if you are playing newer films (generally anything made since the mid-1990s will have an SR track).

If you don't already have a spare preamp card (cat. 240A), you might consider getting one of those as well.

Posted by Tony Bandiera Jr (Member # 2365) on 02-27-2009, 01:14 AM:

Bradley, check the Equipment for Sale listings here, I have some CAT 350's for sale at a screamin deal price... [Smile]

(I hope this post isn't against the rules though.. )

A cautionary note: Please post the serial number of your CP-65 (it's found on a small metal tag on the backplane, or a sticker on one of the rear side ears on later models.)

Certain early CP-65's require a daughterboard to use the 300/350 cards. (I think the CP-65 manual on this site tells which s/n's this affects.)

Posted by Bradley Johnson (Member # 5154) on 02-27-2009, 01:08 PM:

Hey Tony,
Thanks for the tip, I checked your FS add and it said the 350s were sold.....That brings up my next question...Whats the difference between a SR350 and a SR300 card? As your add said that you still had some SR300s available. Seems like I saw something along the lines that the 300s were for a 70MM set up???

thanks for the help!

Posted by Scott Norwood (Member # 30) on 02-27-2009, 01:23 PM:

The cat. 350s only have SR circuits. The cat. 300s also have A-type circuits. In a CP65, there is no benefit to using cat. 300s unless you are running 70mm magnetic sound (in which case you need an external magnetic preamp). Either will work fine for an optical setup, but the 300s are usually more expensive than the 350s. You still need the 222 or 222 SR/A for optical A-type decoding and to set Dolby levels.

There is also a cat. 450, which is an A-type circuit for the 363 NR box, but is not really useful (as far as I know) in a cinema context.

Posted by Bradley Johnson (Member # 5154) on 02-27-2009, 06:43 PM:

This brings me to yet another question that has been nagging me since this project started and that is: Do all current films have an optical soundtrack? I guess what I am asking is that if I have a good reader and a Dolby CP65 can I get good results on all current films? This of course omits a digital platform as the owner is not ready financially on that front. I would really love to see what a modern system looks like as I am learning on truly ancient gear.

Posted by Marco Giustini (Member # 4544) on 02-27-2009, 07:15 PM:

quote: Bradley Johnson
Do all current films have an optical soundtrack?

Yes, SR type.
You can have good results from a good analog sound system. Just remember that

1. It will not sound as a digital one
2. Analog soundtracks are automatically generated by the digital one and - at least here - it's considered a backup soundrack so there aren't much quality controls on it

Marco

Posted by Tony Bandiera Jr (Member # 2365) on 02-27-2009, 09:14 PM:

As Marco has said, yes all current films have optical tracks..but two minor notes:

Not ALL films are done in Digital so the optical track MIGHT be only Dolby A (depends a lot on country of origin, some art/foreign films have Dolby A-type tracks) but he is right the vast majority, even without digital tracks will be optical SR.

As for the idea of the optical being a backup only and not subject to QC, I'd say that's not necessarily true in all cases, but it is derived from the digital masters and it is possible that it isn't qc'd as well as it should be, but so far, most prints I've run across with bad optical tracks have tended to have other problems with the picture portion and sometimes the digital tracks too.

To expand on Marco's first point, he means that the optical track will have three key differences, in order of most noticeable to least noticeable..: The surrounds will be only one channel, not separate left/right; the dynamic range will be lower; and there will still be noticeable bits of noise from dirt and splices.