Film-Tech Forum ARCHIVE: Diference betwen dolby CP-50 and CP-100

This is topic Diference betwen dolby CP-50 and CP-100 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Marin Zorica (Member # 1716) on 04-03-2004, 11:43 AM:

Recently i start thinking about this processors, but i only knew foe technical information from web, can you tell me the deference between this two devices.

Thanks

Posted by Darryl Spicer (Member # 711) on 04-03-2004, 02:54 PM:

The CP100 was I believe the first dolby unit and it provided the ability to run a six channel magnetic sound preamp to it for 70MM playback. The CP50 was a step down version of the 100 to provide more theaters to run 4 channel stereo at a lower price and give the ability to run 4 track magnetic sound.

Posted by Mark Gulbrandsen (Member # 72) on 04-03-2004, 04:16 PM:

Actually much of the circuitry is shared between the CP-50 and 100. Daryl is incorrect... the 100 was actually the first integrated 35-70mm processor that Dolby marketed. However, before that there were seperate single rack space units of which one was the E-3 equalizer unit(contained a CAT 64!) that were wired together to achieve similar results, sorry, can't remember the numbers of the other units involved. Of course all of that was before the optical surround part was even in the field and working. When optical surround was perfected it required an add on unit containing a CAT 116 externally to the CP-100 to make it work. There were SA1, SA2, and the quite rare SA3. A few years later the CP-50 was marketed and was an integrated all in one optical processor at least till the advent of SR encoding...but I'll leave things here.

Mark

Posted by Darryl Spicer (Member # 711) on 04-03-2004, 04:42 PM:

Mark, I am actually partially correct and I wasn't implying that the CP100 was the first actual stereo processor. I ment it as exactly as you stated it the Processor could do optical 35mm and magnetic 70mm sound with Dolby noise reduction.

And from what I understand the CP50 may have similar circutry but can only allow a 4 track magnetic pre amplifier to be used on it. The last time I fiddled with a CP50 was over 12 years ago and the cp100 even longer than that so I can't remember the exact spacifics or complete differances. I do know that the location we had here in town that ran 70mm had to remove the cp50 and put in the cp100 for 70mm.

Question for you Mark. On those units you specified that were used before the cp100, did they have the ability to create what was then called the effects channel that was an essentially flagged on off surround set-up used prior to optical matrixed surround?

Posted by Mark Gulbrandsen (Member # 72) on 04-03-2004, 05:58 PM:

Daryl,
These units were mainly just for A type Mono prints and another box I had decoded Dolby SVA into L,C,R channels and were before the advent of the surround channel. Lonnie or Sam once told me that very few of these were ever manufactured. I had a number of these units years ago but never hooked them up at all. It would be pretty much like the forst CP-100s that lacked surround. I probably should have kept them but I salvaged the cards and threw the rest away.....

Mark

Mark

Posted by John Walsh (Member # 168) on 04-03-2004, 07:44 PM:

I have the original sales brochure for both the CP100 and the E3, but when I scanned and resampled it to the requires 500 pixels, it cound not be read. If anyone wants them let me know and I'll email it privately.

Posted by Sam D. Chavez (Member # 1841) on 04-03-2004, 08:32 PM:

The CP100 had a variety of adaptors for surrounds, the SA2, 3, 4, and the SA5, which was produced to allow stereo Surrounds for Superman 2, Apocalype Now and others before the introduction of the CP200.

The CP50 would not handle mag tracks as there was no entry point for external signals except after the EQ and fader.

Posted by Gordon McLeod (Member # 33) on 04-03-2004, 09:05 PM:

Sam until they brought out that little daughter board for the back plane to allow the mag through the processor
also originally the CP50 didn't have a fader but was inserted just before the old ganged house fader of the mag system
Optical sound on the base units (cp100 and cp50) was only left centre right and then the SA2 allowed QS matrix surrounds for both units with up to the SA4 then the SA 5 was a split surround box for the CP100 (a CP50 chassis) that allowed eq and nr internal to the processor for the extra tracks

Posted by Marin Zorica (Member # 1716) on 04-03-2004, 10:51 PM:

Ok, because these units are old i can get it for lover price, because I've had a mono this units will provide stereo plus noise reduction, what you think which unit i bought CP 50 or

CP 100???, which is better??, of course for analog optical sound.

Posted by Steve Guttag (Member # 268) on 04-04-2004, 01:09 AM:

Alright, the storage pot of worthless information is here.
The first entry into the cinema market for Dolby was the combination of the Model 364 (Contained the Cat. 22) and provided for not only the Academy curve for conventional films in addition to Type-A NR but also a "cleanup" mode for some single-ended noise reduction...it was combined with the E2 (not E3) for both a head end EQ (gain matching and slit loss) and B-chain EQ via the Cat 64 inside. Please note, the Model 364 did not have a preamp, it was presumed you had that already!
Then the CP-100...Sam has already provided the corrections regarding the surround adapters
The CP-50 was the econo processor brought out to provide SVA in existing 4-track magnetic theatres. It presummed you had fader system already. The 4-track magnetic system was a pass-through and the CP-50 merely spliced optical to use the existing fader (often a 3-ganged pot (daven or otherwise) for the stage and a single pot for "effects" (surrounds). In this way, existing magnetic systems were not altered in any way. Only the optical sound received the EQ necessary to make it compete with magnetic. Magnetic tracks back then were mixed with the presumption of no EQ and just the acoustics of the theatre and speakers (typically Altec A-4s).
The next incarnation of the CP-50 is the one most people know and it is the CP-50R...the R stood for "remote fader". This unit was a stand alone system that did not need an external fader system. The only difference was the use of the Cat. 117 for the output card versus the standard Cat. 111.
As to which is better between a CP-50 and CP-100 (the original question)...for optical sound...the CP-50 has always seemed a bit quieter than the CP-100. The CP-100 certainly can be more flexible (and even has a booth monitor function). The CP-50 can now benefit from the improved Cat. 108 (optical preamp), the Cat. 517 and the Cat 560 so that would make the CP-50 yet quieter and have better dynamics (presuming the power supply in yours is up to it...ie. a Cat. 114C or an external supply with good power rails.
Steve

Posted by Aaron Sisemore (Member # 145) on 04-04-2004, 03:39 AM:

There are far more CP50s out there than CP100s, therefore there are more parts/spares for a CP50.

Neither processor is currently supported by Dolby, so you are pretty much on your own if there is trouble.

You also might want to look for a CP55 if you can get one at a good price.

-Aaron

Posted by Sam D. Chavez (Member # 1841) on 04-04-2004, 11:47 AM:

I would vie with Steve on his claim to be the repository of obselete information.

I also certainly agree the 55 is a better stand alone processor, but the price is much higher than the 50 which can be had for anything from $100 to $500.

As to which is more practical, the 50 is easily the first choise as every card in it is supported one way or another. All cards in the 100 except the ones shared by other processors are unobtainable.

There is also the power supply which is all internal. There is no way to repair one except to dismantle the entire frame.

Great museum piece. Ray Dolby wanted it to look sharp and the paint job on the front dooer was done at the same shop that painted Rolls Royce panels. Cost for the job was around $50 in 1977.

Posted by Steve Guttag (Member # 268) on 04-04-2004, 01:35 PM:

Aaron,
The CP-50 is indeed supported by Dolby in just about every way. Heck, the new Dolby price sheet still shows the Cat. 114C for something like $1200. The 113C is also still listed as current as are the other "upgrade" cards.
The CP-100...as Sam notes...is not so fortunate. Anything on the top shelf was unique to the CP-100 (except maybe the meter cards). The bottom shelf had Cat. 64s and Cat. 22s in addition to the "Format modules"...The latest format module, the Cat. 148SR (for use with the SRA-5) has been obsolete for some time. I'm not sure what Dolby's stance is on the repair of CP-100 modules...probably anywhere from...sorry we don't do those anymore to send it in and if we can fix it, it'll cost you and there will be a minimum for doing it.
Steve

Posted by Marin Zorica (Member # 1716) on 04-09-2004, 07:42 AM:

Ok, i know the CP-50 is smaller and similar things, but are the some cards from CP-50 comparable to CP-100, like optical pre amp and similar??

But in original CP-50 and CP-100 without surround chanell what wold be any diference in sound??

Also do somebody have color picture of CP-100, because on Internet exsist only few small black-white pictures, be glad to see this unit.

Posted by Gordon McLeod (Member # 33) on 04-09-2004, 12:50 PM:

The optical preamp is different between a 100 and 50
look in the picture warheouse at Ziporama and there is a colour picture of it

Posted by Mark Gulbrandsen (Member # 72) on 04-09-2004, 06:32 PM:

Gord,

While they are mechanically different they are really just about the exact same circuit give or take a bypass cap or two. the input trannys are also mounted on the chassis as well. The CP-100 fader card is also very similar to the 100's although I believe they use a different fader voltage...ultimately, to control the VCA's. It would be possible to upgrade a 100 but somewhat silly to do so....but perhaps not. The 100 did have the best power supply design that Dolby has ever done, never seen one fail.

There are spare slots down below in which one could install a 108C, a 150E (or whatever), and a 517 to upgrade it to todays performance standards. I did inboard CAT 150D's inside a couple of different 100's on seperate occasions a number of years back. Far as I know they are both still in service.

Mark

Posted by Gordon McLeod (Member # 33) on 04-09-2004, 06:50 PM:

Lonny gave me the list of what to change on the cp100 preamp to raise its cutoff freq for use with reverse scan units and it is a bit different in characteristics to the 108
The fader also has a different current converter than the older CP50 used
I have done many units where I put the smart DSP 150 matrix into the pentoptical slot and used LE and RE as the split surrounds and the S channel as the sub for use with DA20's or DTS