Film-Tech Forum ARCHIVE: Dolby cards

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Posted by Stephen Furley (Member # 1277) on 08-04-2002, 02:51 PM:

Does anyone know where I can find a full list of all the cards, past and present, which Dolby has made for cinema use, with Cat numbers, descriptions, and which processors they can be used in? Also, what the differences were between the various revisions of a card.

Posted by Steve Guttag (Member # 268) on 08-04-2002, 05:05 PM:

I doubt such a list exists in such a fashion.

Some cards, like the Cat. 22, is a cinema card (used in the 364, CP-50, CP-100 and CP-200) but also pro-sound card.

You could make your own list by just going through each processor beginning with the 364 and E2 combination, working your way to the CP-100, then the CP-50, move on to the CP-200, the CP-55, CP-65, CP-500, CP-45, CP-650. Then you have all of the add on items like the remotes, Digital adapters, surround adapters...etc.

Good luck,

Steve

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"Old projectionists never die, they just changeover!"

Posted by Stephen Furley (Member # 1277) on 08-04-2002, 05:35 PM:

quote:
You could make your own list by just going through each processor beginning with the 364 and E2 combination, working your way to the CP-100, then the CP-50, move on to the CP-200, the CP-55, CP-65, CP-500, CP-45, CP-650. Then you have all of the add on items like the remotes, Digital adapters, surround adapters...etc.

It isn't easy, The Dolby site has info on current products only, and only complete processors amd adapters, not the actual cards. Some of the cards, such as the Cat 22, 222, 64, 150 280 etc. I know, but others I have no idea. The Dolby manuals on the Film-Tech site have some info, but not everything. Suppliers of second-hand equipment often list cards they have available, but only by Cat number. There are many that I have never heard of, and there are often several revisions of a card available, again with no indication of what the differences are. I was hoping here would be a definitive list on line somewhere.

At the moment I am looking for a Cat 93, but no one seems to have one of those. Someone else was advertising for one of these on the wanted/For sale forum, I don't know if he managed to find one.

Posted by Ben Wales (Member # 92) on 08-04-2002, 06:15 PM:

Steven,

I would say the best (inforned) person would be Dion Hanson (former Dolby UK) and may well put in touch with some one for the cat 93 cards.

I belive he has a web site under his company name called Cineman, there was a advert in last years Cinema Technology.

Also try Future Projections in London as they may have some.

Posted by Steve Guttag (Member # 268) on 08-04-2002, 07:49 PM:

If you want, post a question on the forum or via e-mail to me...I know most of the cards, particularly the older ones off the top of my head.

For what it's worth, I own a Cat. 93 (12KHz switch card for 35mm 4-track magnetic).

I believe Dolby still has one in stock and it wasn't too pricey. Dolby seems to be revamping their pricing based on current manufacturing costs and desired mark ups. I doubt that when the last Cat. 93 is sold they will make anymore. Personally, I have found the Cat. 93's filter for killing the 12KHz tone to be not good enough...I could CLEARLY hear it still.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Manny Knowles (Member # 1171) on 08-05-2002, 12:00 AM:

You guys must be psychic or something! This is the second topic that came up while I was away that relates to the service call I was making...

While I was over in Freeport, I noticed a number of the CP-45 units were in "Bypass" mode. It turns out that one of the projectionists must've switched them over by accident (or out of total ignorance) because nothing was wrong with any of them.

However, in my search for "something wrong" I went looking for the little fuse on the 511 (?) board....Despite the fact that they all had the little Ziploc baggie with the spare fuses inside, none of the boards in these particular units had a space for such a fuse!

What gives?

Are there various manifestations of the Cat. 511 board?

~Manny (returning to theatres for the last time this century)

Posted by Pete Naples (Member # 761) on 08-05-2002, 01:50 PM:

Someplace I had a list from Dolby UK, something to do with repair charges on current and past boards. If I can find it (don't hold your breath) I'll scan it and pass ti on.

Posted by Frank Angel (Member # 248) on 08-06-2002, 03:21 AM:

Stephen, obviously by the answers already given, you can see that this will be a project not all that easy to accomplish. I would approach this a bit more pragmatically. First I would ask myself, why do I really need a list that is so comprehensive? If it is just a nice thing to have, then after I saw the difficulty in getting all this information, I would ask, but is it something I really NEED? Then I would compile a list of the boards that I would reasonably need to know now and possibly in the future while leaving the rest to the Dolby historians. As an example, will you really ever need to know the card Cat numbers in the original Dolby A N/R unit for the recording studios?

Frank

Posted by Stephen Furley (Member # 1277) on 08-06-2002, 06:24 AM:

Frank, I think you're right. I was hoping that there would be a readily-accessable list somewhere, but it seems not.

One problem I have, is that I never know which cards I might need to know about in the future, a few days ago I wouldn't have thought I needed to know about the Cat 93 surround switch module for the mag pre amp unit, now I need to find one of these.

I think I will start making my own list, and add to it any card I hear about, just in case I need to know about it sometime.

Posted by Steve Guttag (Member # 268) on 08-06-2002, 10:56 AM:

One thing you might try doing is just to pose a question here on the forums with what it is you want to do. Let us worry about the mechanics of accomplishing it. You will, no doubt, be assaulted with several options and opinions for accomplishing any particular project.

For instance...if you posed the question of wanting to run 35mm 4-track magnetic films with your Dolby CP-200 processor, "what do I need?" That question would eventually get you to the Cat. 93.

Try to always state the equipment you have though. For instance, if you posed the same question but had a Dolby CP-65 or CP-500 or an Ultra, Smart or Panastereo brand processor. The suggestion may not even include the Dolby preamp and Cat. 93 switch card. The are other obsolete 35mm magnetic stuff like the SMART SMP-430 or the rather new Panastereo CSP-4600 that may suite your needs better and is readily available.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Stephen Furley (Member # 1277) on 08-07-2002, 04:25 PM:

Steve said:

quote:
I have found the Cat. 93's filter for killing the 12KHz tone to be not good enough...I could CLEARLY hear it still.

Acording to the short section on the Cat 93 in the MPU-1 manual, the low pass filter should pass the signal up to 8kHz. It doesn't say how sharply it should cut above that, but it shouldn't be difficult to get enough dBs down at 12 kHz that you couldn't hear the tone. If you can hear it, there would seem to be three possible explanations:

1. Your Cat 93 is faulty. Have you heard another one?

2. The Cat 93 is badly designed.

3. The film had a tone on it at the wrong frequency. Hove you heard it with more than one film.

Do you know which of these is the case? Or is it something else, which I haven't thought of?

Do you know at what level the tone should be recorded on the film?

Posted by Steve Guttag (Member # 268) on 08-07-2002, 04:49 PM:

Very good questions!

Unfortunately, I'd say it just isn't the best of designed cards. Also, most surround arrays back then were simple 8" speakers with less than steller response. On a modern system that will be flat out to 20KHz, it will be much more apparant. I have heard at least 3 Cat. 93s running different films and I have always noted and was botherd by the 12KHz tone. It is substantially reduced but not enough for me.

Now another person in the room when I remarked on the tone said he couldn't hear it (he was a bit older than I...still is).

One thing the Panastereo CSP-4600 has in it is a notch filter plus a user selectable 8KHz low-pass filter to kill it off.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Steve Kraus (Member # 476) on 08-07-2002, 05:47 PM:

Gracefully aging Steve remarked:
>(he was a bit older than I...still is)

Not as a percentage!

Posted by Mark Gulbrandsen (Member # 72) on 08-07-2002, 10:00 PM:

OK Mr Guttag,
Lets see how well polished you are on your Dolby card numbers....Here is a question that you may or may not know the answer to. If you know the answer then I promise to stop making fun of your shoes at Vegas......But if you don't you'd better showup barefooted

.
What is a CAT 90? And no paging Lonnie in the middle of the night to get the answer!
If no one can guess this I'll post the answer in a day or so...or after everyone's had enough fun with it.
Employees of Dolby Labs are automatically disqualified from this contest. Offer void where prohibited!
Mark

Posted by Michael Schaffer (Member # 1204) on 08-07-2002, 10:16 PM:

Hello Mr Furley,
I found a list from a Swedish equipment dealer which lists the cards, their functions, and accessories for currently available processors. While it is obviously not complete, it might be a good starting point to draw up a complete overview. I will send it to you by eMail.
Michael

Posted by Gordon McLeod (Member # 33) on 08-07-2002, 10:24 PM:

It is used with the 360 and the E2 equalizer and it is probably the optical preamp or changeover

Posted by Mark Gulbrandsen (Member # 72) on 08-07-2002, 10:57 PM:

AHHHHHHHHHHHCH
Sorry but you're wrong. You have two trys left before you're out.....

Posted by Michael Schaffer (Member # 1204) on 08-07-2002, 11:52 PM:

A cat 90 is a four-wheel all-terrain vehicle specially designed for young adventurers.
Michael

Posted by Mark Gulbrandsen (Member # 72) on 08-08-2002, 01:00 AM:

AHHHHHHHHHHHCH
Sorry but you're wrong. You have two trys left before you're out, you're headed entirely in the wrong direction.

Posted by Stephen Furley (Member # 1277) on 08-08-2002, 01:21 AM:

How widely used were the 360/E2 combination? I only ever saw them in a couple of places.

Posted by Frank Angel (Member # 248) on 08-08-2002, 04:04 AM:

Steve G said: >On a modern system that will be flat out to 20KHz, it will be much more apparant. I have heard at least 3 Cat. 93s running different films and I have always noted and was bothered by the 12KHz tone. It is substantially reduced but not enough for me. <

Nor me. I used a 10% frequency-adjustable 12kHz notch filter that originally came with the Altec mag tube preamps. It never made that 12kH inaudible. I also found out that in the heads I had, and I am sure you will find this in most of the older original penthouse heads, the 12k bleeds into the other heads right in the head cluster itself, especially the track that is right next to channel 4....what is that, the Center channel or Left, I can't remember).

You need to listen to the film played with the surround off and with only the front channels playing. If you still hear the tone, then you have a bleed problem, and I'll bet it's not your electronics down the line, but it originates right in the head cluster itself. I mean they recorded that damn thing at 0db -- were they on crack when they thought up this system? I am sure at 0db it regenerates itself into the coils of the other heads in the cluster by sheer induction. The old literature kept referring to the 12kHz tone as "inaudible." Yeah, maybe to someone in their 90s.

What I wound up doing was buying three additional, high-quality Altec studio notch filters for the other three front channels. Also, the speed of the machine may affect the amount of attenuation the notch filter can achieve; if the machine is running faster or slower than precisely 24fps, that tone will be slightly off and the filter will not be hitting it right on the head. But you have to be really off to make a significant difference.

We never used the original relay to kill the surrounds in our jerry-rigged setup -- we used a piece of studio gear called an Auto-Attenuator; it was a neat little compact unit made by Fairchild that simply attenuated a signal whenever it dropped below the level you set. It was a piece of cake to align -- you just passed the surround signal through it and played a reel with a section with no surround audio (except whatever bleed was present from the front channels -- the reason for the 12kHz trigger in the first place). Then you set the unit threshold control so that the unit completely attenuated the signal. When the surround audio kicked in, you set the threshold on the unit to pass the signal. It worked like a charm. Only recently did I replace it with a Valley People compander with fifty-million controls on it that all have to be precisely tweaked. I moved to the compander only because it can be used to add a bit of downward expansion for the surround channel on Dolby A & SR prints, helping to slightly attenuate the crosstalk in quite passages -- good for the folks who are not in that perfectly timed-delayed sweet spot -- a real help in large halls like ours.

Thankfully it didn't take them long to see the error of their ways and they began releasing mag prints with no trigger tone at all --dropped it like the rotten hot potato it was. I have played many mag prints with no 12khz trigger, just audio on track 4. Nice thing about the Auto-attenuator, it doesn't care if there is a tone or not, it still worked fine, cleaning up crosstalk even though there was no trigger tone because it uses the audio level itself to activate the attenuation factor. Come to think of it, you could also adjust the decay time which allowed the unit to gently reduce the volume when the tone disappeared, unlike the original relays which just clicked the speakers off abruptly.

Mag -- it had it's problems, but it was a sweet-sounding, DISCRETE system -- a claim Dolby, as much as they bad-mouthed the mag system in their early manuals, could never make.

Posted by Steve Guttag (Member # 268) on 08-08-2002, 06:42 AM:

Mark, I'll have to give it some thought...it's number places it squarely in the era of the CP-100 and MPU.

BTW...it is the 364 not 360. The 364 was cinema specific and had "clean-up" mode.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Stephen Furley (Member # 1277) on 08-08-2002, 07:18 AM:

quote:
Thankfully it didn't take them long to see the error of their ways and they began releasing mag prints with no trigger tone at all --dropped it like the rotten hot potato it was. I have played many mag prints with no 12khz trigger, just audio on track 4. Nice thing about the Auto-attenuator, it doesn't care if there is a tone or not, it still worked fine, cleaning up crosstalk even though there was no trigger tone because it uses the audio level itself to activate the attenuation factor. Come to think of it, you could also adjust the decay time which allowed the unit to gently reduce the volume when the tone disappeared, unlike the original relays which just clicked the speakers off abruptly.

Do you know when they dropped the 12 kHz. tone? I agree, it was a bad system, I know there were a few 4 track releases with Dolby A, it would seem highly probable that these did not have it, but was it dropped before then? I want to install it in the setup that I am doing, mainly for historical completeness, but I don't know if it will ever be used, other than for demonstion purposes.

Most of the 4 track shows I saw seemed to make no use of the surround channel anyway, did many films not use it, or did the cinema just turn it off, possibly due to problems with the 12 kHz. system.

I can think of three cinema sound systems which used control tones for vaious purposes:

The Fantasound TOGAD.

The Cinemascope 12kHz suround switch.

Perspecta.

Were there any others?

It is interesting that the oldest of these systems (Fantasound) was the only one which kept the tones on a separate track, both of the others combined them with the programme sound, thereby causing problems with eliminating them in the theatre, and limiting the bandwith available for the audio. Seems like a step backwards to me.

quote:
Mag -- it had it's problems, but it was a sweet-sounding, DISCRETE system -- a claim Dolby, as much as they bad-mouthed the mag system in their early manuals, could never make.

I still think that both the best, and the worst, film sound that I have heard has been analogue magnetic; it's a pity that it wasn't always heard at its best. Sometimes it suffered from partial erasure, loss of high frequencies, worn stripe, worn heads, poor stripe application (more of a problem on 35mm than on 16 or 70, due to the narrow stripes used) and various induced clicks, pops and other noise.

Posted by Mark Gulbrandsen (Member # 72) on 08-09-2002, 02:37 AM:

The CAT 90 is a line amplifier card.
Mark

Posted by Steve Guttag (Member # 268) on 08-09-2002, 07:45 AM:

Line amplifier card used in....?

It is definatley CP-100 era...the Cat. 91 is in the CP-100, the Cat 92 is in the MPU and the Cat. 80 series stuff is in the CP-100 as well.

Steve

------------------
"Old projectionists never die, they just changeover!"

Posted by John Pytlak (Member # 331) on 08-09-2002, 09:27 AM:

Hard to believe that someone at Dolby would not be able to supply a complete "official" list of cards and functional descriptions. They should really have this on their website.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Mark Gulbrandsen (Member # 72) on 08-09-2002, 11:16 AM:

It was in its own stand alone unit that looked like an E-2 Chassis. I long ago use the chassis for something more useful and I do not remember its model number although there was also a three channel(front) decoder card(half a cat 150) inside along with the Cat 90. I suspect it was Dolby's very first version of the decoder unit and set up to directly drive the power amps through an old style three gang(like Altec) master fader. It would definately be just before the CP-100 emerged. Now its ok to page Lonnie!

.
Mark

Posted by Frank Angel (Member # 248) on 08-09-2002, 04:26 PM:

Stephen,

I think while the system was still CinemaScope and adhered to all Fox's specifications, including the curved "magic mirror" screens, the trigger tone was included. But once CinemaScope was abandoned by Fox, I think that would be when the studios began releasing those few roadshow pictures that did get the mag treatment, without the trigger tone. I've run titles as early on as MY FAIR LADY, CAMELOT, THE UNSINKABLE MOLLY BROWN, BECKET and in later years, LADIES AND GENTLEMEN THE ROLLING STONES, WOODSTOCK and MONTEREY POP -- none of them had the surround 12kHz. Yet 2001 did. So I guess it was the producer's choice, not an industry standard change. But that is only my guess; if there was a change in a standard regarding mag tracks, John P. can enlighten us.

Posted by Steve Guttag (Member # 268) on 08-09-2002, 09:35 PM:

The CP-100 had a bunch of cards below Cat. 90 so I would be surprised if it came out prior unless the CP-100 is still in development.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Mark Gulbrandsen (Member # 72) on 08-09-2002, 09:41 PM:

Well, you wouldn't use a cat 90 in a CP-100 at all. I remember Sam or Lonnie telling me that it was originally a studio application card or something to that extent. Apparently a few were used in building primitave cinema processors, pre CP-100. Perhaps just used for the first few dolby released films in several locations.
Mark

Posted by Michael Schaffer (Member # 1204) on 08-09-2002, 10:35 PM:

Are there still CP100s being used anywhere? If so, how do you service them? Can you use some of the later cards to replace those in a CP100 or would you have to check and repair all the parts on a defective card yourself?
Michael

Posted by Stephen Furley (Member # 1277) on 08-10-2002, 03:08 AM:

The Projected Picture Trust recently installed a CP-100 in the Enigma Cinema at Bletchley Park. Not a 'normal' cinema, but certainly a 100 still in use.

Posted by Mark Gulbrandsen (Member # 72) on 08-10-2002, 02:06 PM:

Many are now in use in home film theatres.
Mark

Posted by Stephen Furley (Member # 1277) on 09-12-2002, 05:47 PM:

Frank said:

quote:
Only recently did I replace it with a Valley People compander with fifty-million controls on it that all have to be precisely tweaked. I moved to the compander only because it can be used to add a bit of downward expansion for the surround channel on Dolby A & SR prints, helping to slightly attenuate the crosstalk in quite passages -- good for the folks who are not in that perfectly timed-delayed sweet spot -- a real help in large halls like ours.

Large venue, and you're still running mag prints, that sounds interesting, what sort of place do you work in? Is there much still available on mag over there, there's just about nothing here.

Posted by Frank Angel (Member # 248) on 09-13-2002, 01:33 AM:

Actually not much here either. Kit Parker had a lot of mag ranging from decent to barely runable. Now Warners and MGM still have some mags but most come from private archives, like UCLA, MOMA and a few private collectors. We'll keep the mag penthouses because we still have private sources, but the studios have only kept the IBTechs; any of the Eastmans have been junked because they are all red. That doesn't leave much.

Posted by John Pytlak (Member # 331) on 09-13-2002, 05:46 AM:

Frank said: "any of the Eastmans have been junked because they are all red. That doesn't leave much."

The acetic acid vapors from mag-stripe induced vinegar syndrome on acetate print film accelerated the fading of the dyes in color prints made prior to the early 1980's, when Kodak introduced more stable dyes. Both dye fading and vinegar syndrome are greatly slowed by recommended cool and dry storage conditions, and either vented storage containers, or sealed containers with Molecular Sieves to adsorb the excess moisture and acid vapors.

Posted by Frank Angel (Member # 248) on 09-14-2002, 01:59 AM:

I must say, John, those recommendations have served us very well. We have quite a number of original mag prints from the 60s and 70s that are stored at about 55 degrees in open air that is moving and constantly being exhausted. None of these prints have gone into acidosis, although most have warmed considerably, they still retain enough color to be enjoyable to watch. I only wish I had known about all this much earlier on -- perhaps I could have extended their color life a bit longer.

Posted by Steve Kraus (Member # 476) on 09-14-2002, 10:42 AM:

Going back to the CP-100, is there any reason *not* to use