Film-Tech Forum ARCHIVE: Questions about outputs from the CP200

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Posted by Sean Weitzel (Member # 244) on 07-05-2011, 10:34 PM:

Hi folks.

I ran for several years a pretty much stock CP-200 with an MPU-1 in my screening room with only L, C, R, and S configured. Recently I installed a SRA-5 for SR, a DTS6, and an SDDS that I have had sitting around for 3 years. DTS is inserted between the JM11/21 connectors and the outputs from the CP-200 go into the aux in on the SDDS DFP-2000 with Aux out going to amplifiers. I currently only have a cat 160, but am keeping an eye out for a cat 560 to replace it.
My question is basically how to go about routing the surround outputs. I can understand that the P and Q outputs are Lsur and Rsur and should go to appropriate amps/speakers. Am I correct in assuming that the mono surround from the CP should go to it's own amplifier for a center surround speaker?

Also, 2 more questions:
Besides a cat560 and I think I read a cat 217, are there any other cards that will need to be upgraded for full digital support?
and finally, is an aux rack absolutely necessary to provide format 43 with SR and stereo split surrounds? Where does the subwoofer come from in this format? the SW out terminal on the processor?

thanks in advance.

Posted by Steve Guttag (Member # 268) on 07-06-2011, 06:22 AM:

The Mono surround (S) is just that, the mono surround. It is vary rarely used as a back-surround though some profess that in long/narrow cinemas that it helps to pull the sound back a bit. Dolby does have a method to use the AUX rack to house a second Cat 150 and a logic board (Cat 814) plus an external logic/audio board to allow the "S" channel to be the EX channel (the external logic/audio board took care of switching the normal P/Q or S audio feeds to the proper rear surround amps.

So, in short, if you are just going for 5.1 audio, don't connect up the "S" channel.

Aside from the Cat 560 for digital subwoofer (and a crappy surround EQ), the Cat 517s will complete the CP200 for digital audio. The sound quality improvement with the Cat 517s is significant in terms of S/N and distortion.

As for format 43...you need to house the Cat 158 (stereo surround) module somewhere...also you need to house two additional noise reduction cards for format 43. The Aux rack is the logical place. And, while you are at it, you then have a place for real EQ cards.

Yes, the S/W terminal remains the S/W terminal for ALL formats.

-Steve

Posted by Sean Weitzel (Member # 244) on 07-06-2011, 11:31 AM:

Thanks Steve, as always for your quick and helpful info.

I assume then, that if I wish to run an optical Dolby SR print, then the format 5 will send the mono surround info to both P and Q outputs equally? Is format 4 no longer relevant for running Dolby A with surround? or will the mono surround go to the P an Q?

Posted by Steve Guttag (Member # 268) on 07-06-2011, 04:31 PM:

Mono surround is always sent to both P and Q equally (except for microphone but that is a simple diode fix).

Format 04 remains for Dolby-A movies and works fine with P&Q

You can refer to the AFI/Silver for a reasonably well tricked out CP200 and the formats I have done. http://www.film-tech.com/warehouse/picview.php?id=4786&category=1

Note, you can ignore the Flat/Scope varients...the AFI/Silver has 5 stage channels and uses them to keep the stereo image on the screen as well as for ToddAo or SDDS-8.

-Steve

Posted by Sam D. Chavez (Member # 1841) on 07-06-2011, 04:42 PM:

Nothing to disagree with here. I do have various bits for the 200 people keep dropping by my door as if they are returning them back to the original maker.

Among the stuff, are a couple of empty aux racks, lots of Cat. No. 64's, and sets of 560/517's.

Posted by Steve Guttag (Member # 268) on 07-06-2011, 05:42 PM:

Note...we are doing PS1B upgrades too that will significantly quiet a CP200 down (especially if you have the Cat 517/560 upgrades). Hiss and hum just about disappear.

A problem with the PS1B and all Dolby processors prior to the CP55 is that their power supplies are very load dependent. The PS1B may output 14-15 Volts before it is hooked to the CP200 but you are lucky if the +/-14V rails are at 12.5 volts once all are on-line. Also, the ripple is quite measurable. When we are done, you get a solid, regulated power rails. Everything functions as before, including having a spare supply. We will even change the pilot lamp to an LED version.

The CP200 remains the best processor, ever.

-Steve

Posted by Sean Weitzel (Member # 244) on 07-15-2011, 11:07 PM:

Hi Folks,

I'm finding that I can get dolby tone out of the P and Q, but my DTS6 seems to not be passing anything to the P, Q, and SW. I'm pretty sure the DTS6 is set for 5.1. Are the 560/517 upgrades required to pass split surrounds as well as route SW through the fader? Also I found it rather interesting that the DTS6 appears to pass the sub frequencies to Le and Re. Is this by design?

Posted by Steve Guttag (Member # 268) on 07-16-2011, 07:34 AM:

Yes, the DTS system is only really a 5-channel system...they use the surrounds channels to encode the subwoofer on the lower frequencies (and HPF the surround channels...however on sweeps, you can often hear the woofers flap in surrounds as they still get some of the subwoofer information). DTS then feeds the subwoofer signal (LPF of the surround channels) to Le/Re and SW.

There were many CP200 installations (particularly early ones) that skipped putting in Le/Re but hooked their subs to the Le/Re terminals...as such, feeding the subs to all three covered their bases (no pun there). If you have Le/Re and S/W on your CP200, all three will get the signal BUT Le/Re will be 10dB down since they do not receive the boost UNLESS the signal comes before the dual equalizer/filter card, like 70mm. Since DTS comes in on JM21 on the rear, the boost is skipped.

The Cat 517s are not required for subs...but the Cat 560 is. The stock Cat 160 does not have a "digital" subwoofer input. If you are real clever, you can set up a signal path that will let the subwoofer come in on the MAG A or B terminals (Le/Re) and configure the CP200 to use them for the subwoofer in...it is the wrong way to do it but I can be done, depending on what else is on the CP200.

The factory way, when the DTS6 came out was to use the "STEREO" connector to feed the sub to a relay board that would attach to the S/W output terminal of the CP200 and connect the sub feed to the amps to the relay board... you did NOT have volume control over the subwoofer. Later DTS6 units moved the relay internal but you still needed to use the "STEREO" connector for this.

-Steve