Film-Tech Forum ARCHIVE: Will a CP-200 without a cat 160 card output anything?

This is topic Will a CP-200 without a cat 160 card output anything? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Sean Weitzel (Member # 244) on 10-28-2008, 10:54 PM:

I am assembling the sound rack in my home screening room. The CP-200 I acquired several months ago is stock (with cat 22's and all) and has all the cards except the Cat 160 optical bass extension card is missing. (anyone got a spare cheap?) If I power this baby up without this card will I get any sound out of it at all or is this card a requirement to complete the signal path? Sorry in advance for the newbie-ish question. I'm not a pro cinema tech and this is my first exposure to a real dolby audio processor.

Posted by Sam D. Chavez (Member # 1841) on 10-28-2008, 11:11 PM:

I have not looked at the block diagram in a while, but you will get no optical analog sound without one. Optical sound will work in bypass after a fashion.

I have a bunch of them in my piles of stuff. Name you price, wine, popcorn, whatever.

Posted by Sean Weitzel (Member # 244) on 10-28-2008, 11:46 PM:

If you are still up in Martinez, I will hand deliver a bottle of your favorite wine in exchange for one good sir! [Smile]

send me an email through the forum.

Posted by Darko Milev (Member # 4742) on 11-01-2008, 04:54 AM:

Mr.Martinez,
does your dungeon warehouse contains some 108C and 150E/F for sale?
Mind you, I am located in VERY strong wine region in Europe!!! [Big Grin]

Regards,
Darko

Posted by Sam D. Chavez (Member # 1841) on 11-01-2008, 10:41 AM:

It's Mr. Chavez or Sam to my friends. 108C's are definitely gone but there may be a 150 or two.

Posted by Marin Zorica (Member # 1716) on 11-02-2008, 09:38 AM:

Hi MR! :-)

Anyway...what is a big difference between 108 and 108C...I did see only difference in opamp ??

P.S. Darko, please read PM!

Posted by Sam D. Chavez (Member # 1841) on 11-02-2008, 11:01 AM:

The main difference is in extended freq. response and improved separation between left and right channels.

Posted by Marin Zorica (Member # 1716) on 11-02-2008, 11:34 AM:

Improved separation on CAT108?? What this mean...I know that all four indentical inputs...don't know how they did make "more" separation.

I know major difference was better response....but I'm interested how that they achieved....new design or?? Because they are similar to me, only I newer saw 108C schematic.

Posted by Sam D. Chavez (Member # 1841) on 11-02-2008, 12:30 PM:

There was crosstalk between left and right channels because of the layout of the 108 circuit board and the choice of pinouts on the edge connector and backplane layout. This limited the ultimate performance of the Cat. 150 matrix decoder in its ability to accurately "steer" the signal to the appropriate channel.

The C version dealt with this with improved board layout and anti crosstalk circuitry. How exactly it worked I don't recall anymore, but it did improve the performance.

Posted by Marin Zorica (Member # 1716) on 11-03-2008, 08:15 AM:

quote: Sam D. Chavez
The C version dealt with this with improved board layout and anti crosstalk circuitry. How exactly it worked I don't recall anymore, but it did improve the performance.

Anti crosstalk.....okay this is funny for them, also didn't know that they needed 10 years to figure out that....

Also I checked.....op amp are powered ONLY by single rail supply.....maybe they figured out in C that would be better to go on double rail supply??

Posted by Sam D. Chavez (Member # 1841) on 11-03-2008, 10:03 AM:

It's all about priorities. The fact that Dolby actually improved the performance of processors already out of production is to be commended. Many companies just make you buy a new unit to get improved performance.

Posted by Steve Guttag (Member # 268) on 11-03-2008, 01:59 PM:

The crosstalk issue was actually addressed in the 108-4.

The 108C widened the frequency response (works much better on reverse scan readers) and also used a ground-plane fill on the PCB to lower the noise.

Steve