Film-Tech Forum ARCHIVE: Dolby Cat64 or 64B ?

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Posted by Nic Dreier (Member # 333) on 08-20-2000, 04:22 AM:

Hi there,

Lately I checked our soundequipment, when I discovered, that there were two different types of the EQ-card (Dolby Cat64 and Cat64B) installed in the units. Does anyone know the difference between these two cards?

Thanks for your help

Best Regards

Nic

Posted by Ari Nordström (Member # 288) on 08-20-2000, 02:44 PM:

Well, the 64B is a later model, with greatly improved filters and a (much) higher signal to noise ratio. The Cat 64's been around since the CP50, at least. I do believe that they are pin compatible, though (can anyone confirm this?), so if you can choose, take the 64B.

Posted by Scott Norwood (Member # 30) on 08-20-2000, 03:59 PM:

I'm quite sure that the 64 is interchangeable with the 64B. On the used market, there's a big price difference between original CP50s and upgraded ones (usually with the 108C preamp card, the 150E or F matrix, the 64B EQ cards, and maybe the 160 subwoofer card and 113C automation switch card).

Posted by Alan Lyman (Member # 557) on 08-21-2000, 12:18 AM:

The two Cat's 64 are interchangeble.
Please note though,that that the 64,has trimpots for level,and these should be adjusted when using it with SR-cards in a CP50.

Posted by Kevin Crawford (Member # 469) on 08-21-2000, 01:56 AM:

There is a new sub card for the CP 50. It is the CAT 560. Not only does it give a sub, but also split surrounds with a parametric EQ. I have not seen one, but I have talked to Dolby about it. It lists for about $500.

Posted by Aaron Sisemore (Member # 145) on 08-21-2000, 04:03 AM:

Don't you have to do some major modifications to the backplane of a CP50 to use the 560? I am pretty sure its not plug-and-play...

Aaron

Posted by Brad Miller (Member # 2) on 08-21-2000, 05:46 AM:

Yes, there are modifications to be done to the main board.

Posted by Bill Purdy (Member # 202) on 08-21-2000, 09:15 AM:

The Cat. No. 64 actually goes back much earlier than the CP-50. Not only was it used in the CP-100, but in the original Dolby Mono system. That is what the "Head Equalizer" adjusters are about. Dolby tracks didn't have the same curve as the old Academy curve and so they needed some extra HF tweaking.

------------------
Bill Purdy
Component Engineering

Posted by Ken Jacquart (Member # 369) on 08-21-2000, 09:29 AM:

Be aware that the Cat. No. 517 / 560 combination does not provide split surrounds while installed in a CP50. It does provide surround and subwoofer EQ of course.

ken

Posted by Kevin Crawford (Member # 469) on 08-21-2000, 01:43 PM:

Ken what does the CAT 517 do?

Posted by Brad Miller (Member # 2) on 08-21-2000, 02:58 PM:

The 517 is an upgraded version of the 117 output card. There are no new features.

Ken, properly modified, a CP50 can run split surround with a second 117 in the spare slot with a direct JM11/JM21 digital loop. (Of course, I'm sure you were referring specifically to "unmodified" units.)

Posted by Chris Trainor (Member # 9) on 08-21-2000, 08:45 PM:

I've actually noticed that there are 2 different versions of the Cat 64B. One has the older style (rounded edge) trimpots and the newer one has the flat trims. I havn't found much difference in sound quality, but with just a quick look you can see if the board you have is one of the new 64b's as opposed to the original 64b.

--Chris

Posted by Chris Trainor (Member # 9) on 08-21-2000, 08:46 PM:

Also, actually, when you use either the 517, or 560 there are mods you have to do to the backplane. Actually if you use both, there are some separate mods. I'm pretty sure Brad has the manuals online as to how to deal with them. It's not too tough, but it's a real pain in the neck to go back once you've made them.

Posted by Andrew Poulain (Member # 457) on 08-22-2000, 03:41 PM:

The Cat No. 517 card has improved VCA/Line amplifers built into the card. There is an improvement in headroom and has lower distortion over the older Cat No. 117 cards. Additionally there is a treble boost for the screen channel speakers. This is good for sites that have older passive crossovers, or active crossovers without screen loss compensation.

------------------
Andrew M. Poulain
Field Service Technician
THX Division
Lucasfilm Ltd.
apoulain@thx.com
415-492-3955
Cel: 415-302-0825

Posted by Ken Jacquart (Member # 369) on 08-22-2000, 09:19 PM:

Brad, now how are we going to sell any CP650's having revealed the secret mod to the CP50!

ken

Posted by Brad Miller (Member # 2) on 08-22-2000, 11:38 PM:

Bring back the CP200!!!

By the way, where's that new Aux rack?

Posted by Mark Gulbrandsen (Member # 72) on 08-23-2000, 04:43 PM:

Actually beware that a cat 64B will not work in a CP-100. The 517's have drastically better vca faders. T he old 117's had horrible crossover notch at high frequencys. They almost appear to be class B based amplifiers. The new card is a must if you own a CP-50.
Ken,
Yes, bring back the 200!!
Mark

Posted by Joe Grace (Member # 341) on 08-23-2000, 06:48 PM:

Does dolby Still manufacture the CP-200? If not then why did they take it away? It seems that it was a pretty good processor.

Posted by Gordon McLeod (Member # 33) on 08-23-2000, 08:35 PM:

Dolby does not build the CP200 anymore RIP
the story I heard was
It was two expensive since 70mm was obselete
It was to complex for booth ushers to understand
It was all singing all dancing digital

Posted by Ken Jacquart (Member # 369) on 08-23-2000, 09:10 PM:

I agree that the CP200 with the 517/560, 150D (or E), 64B's, Acc unit, etc.. is pretty much impossible to beat in many areas. I think Gordon is pretty close... what would this processor cost to build today? How many would be sold at that cost today? ... you know, business stuff. Hey, it should be a pretty hot commodity on the used market! Oh, by the way, Lonny is the expert with that thing for those of you who want to day way crazy stuff out there!

ken

Posted by Steve Guttag (Member # 268) on 08-23-2000, 09:13 PM:

Actually, the CP-50 can indeed run with "split surrounds" with just one Cat. 560 and one Cat. 117 and I have done so. Heck the Cat. 560 has all of the Rs stuff for the CP-50, VCA, EQ, SPI, trim...what more can one ask?

There are a couple of "watchouts" though. If not done properly, you will get an out of phase situation between Ls and Rs.

Our daughterboard we made a few years back actually allowed the exhibitor to select which cards they wanted to upgrade and also would "look" at the Cat. 22 slots to see if Cat. 280Ts are installed and boost the gain by 3dB. We also added a Hearing Assist output to the unit.

So there Mr. Ken ;-)

Steve

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

Posted by System Notices (Member # 2357) on 06-20-2005, 02:12 AM:

It has been 1761 days since the last post.

Posted by William Hooper (Member # 71) on 06-20-2005, 02:12 AM:

quote:
Please note though,that that the 64,has trimpots for level,and these should be adjusted when using it with SR-cards in a CP50.

I just pulled from a CP55 a cat64 which was causing incredible distortion.

Where are the setup procedures for a cat64 documented for setting the input, output, hf, & gain trimpots?

Posted by Sam D. Chavez (Member # 1841) on 06-20-2005, 11:33 AM:

William,

These procedures were not updated in the manual as Dolby introduced new cards, so all the procedures in the manuals are pretty useless.

The best way according to me is to set the input trims all the way off and set each output trim to about 200 mVolts (measured at the input to the VCA card) of pink from a Cat. 85 After setting house EQ, and before setting final sound pressure levels.

The method described in various versions of the CP50 manual rely on using test film and this in turn is thrown off by the state of the A chain including SR cards. Setting it from a generator goes around all this.

[ 06-21-2005, 12:18 AM: Message edited by: Sam D. Chavez ]

Posted by William Hooper (Member # 71) on 06-21-2005, 06:30 AM:

Thanks Sam!

Posted by Louis Bornwasser (Member # 3063) on 06-21-2005, 03:27 PM:

These cards were originally used in the CP-100 and before. The set up instructions in these old processors were unique unto themselves.

If you have a CP-50 manual, the set up instructions are correct there, since 64 and 64b were both supplied for the 50. All other (later) Dolby products used the 64b and did not show the level set up instructions since they had become unnecessary.

Louis

Posted by Sam D. Chavez (Member # 1841) on 06-21-2005, 07:11 PM:

Au contraire (sp)Louis,

There were several versions of the CP50 manual. The older ones refer to a procedure back to the time before the Cat. 150 card.

It's best to ignore it altogether in this regard.

Posted by Ken Jacquart (Member # 369) on 06-21-2005, 11:42 PM:

Yup, I would follow Sam's advice... "The best way according to me is to set the input trims all the way off and set each output trim to about 200 mVolts (measured at the input to the VCA card) of pink from a Cat. 85 After setting house EQ, and before setting final sound pressure levels."

Also, I seem to recall some service calls where static in a screen channel was caused from a "dirty" trim pot on a Cat. No. 64 card. Simply using a "Dolby" tweaker and working the pot back and forth would fix it up nicely for a period of time... just remember, only a Dolby tweaker will work properly in this case.

Posted by William Hooper (Member # 71) on 06-23-2005, 06:17 AM:

Where does the orphan Head Equalizer section of the Cat64 come into the signal path?
Is it something related only to the mag path? I can't see it in any path in the CP50 manual, but there's no backplane diagram.

Looking at those diagrams in the CP50 manual here will make you blind faster than drinking methanol.

Posted by Louis Bornwasser (Member # 3063) on 06-23-2005, 08:00 AM:

The head equalizeris physically located on the cat 64. However, its input/output are seperate from the eq section. You could, however feed the head eq section then loop over to the third octave section with a jumper.

I believe this was left off of the 64b.

Louis

Posted by Steve Guttag (Member # 268) on 06-23-2005, 07:16 PM:

The "head EQ" was really for the "E2" frame. It used YOUR preamp and then provided a means to adjust for gain and slit loss. The signal then went to the 364 frame for NR and then back to the E2 for equalization of the auditorium. Thus the 364/E2 system was born.

The Head gain and EQ controls have no purpose on the CP50, CP100 or CP200.

Posted by Sam D. Chavez (Member # 1841) on 06-23-2005, 08:00 PM:

The Head EQ was part of the original Dolby Mono system that consisted of a 364/E2. The 364 was a Cat. 22 frame with some extra features and metering. The E2 was the original Cat. No. 64 frame.

I believe the head EQ was an attempt to do slit loss EQ to the house preamp.