Steve - is there enough headroom in the CP-50 bare bones output card to handle the digital format?

Aaron - I still have to agree with you. CP-55 or CP-65 would be better, and cost less in the long run "to do".

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I never said you said the CP-50 couldn't be done...I claim that updating a CP-55 isn't any easier nor cheaper than the CP-50 nor is a better choice. And yes, the Cat. 117 (stock on the CP-50) can handle the dynamics of digital tracks...can it be improved with the Cat. 517? Sure. The CP-55 has the older TDA series of VCA whereas the Cat. 517 uses the superior dbx series of VCA that is used on the Cat. 441 and Cat. 560.

As to Dolby's recommendations...big deal...you may be hearing an opinion rather than any technical fact...clearly they did think about the CP-50 running digital since the Cat. 560 can handle Right-Surround which is only useful on the CP-50. Dolby even layed out an adapter board to mount on the CP-50 backplane...assigned it a Cat. number and everything.

Steve

Please don't think that I am recommending that people go out and scrounge up CP-50s with digital in mind...just if you have them that upgrading is an option that shouldn't be dismissed out of hand. And upgrading to a CP-55 is not what I would call a cheaper nor superior move. It all depends on how far gone the CP-50 is and if the CP-55 already has been upgraded.

As to hooking up a DTS unit to a CP-50 using nothing more than DTS' D567 board makes some sense. The quality of the sound coming from the DTS unit in the 4.0 or 4.1 configuration would sound substantially better than optical...better frequency response, better S/N, better separation...no film noise...and if the theatre comes into more money, then processor upgrades or replacement to somthing more current can be considered and the digital investment is already in place.

As to the speakers...even if they are Altec A-7s the Altec 800/900 series drivers handled more than 9 watts, or whatever you stated. Futhermore, the drivers can be upgraded with new higher power diaphragms (909 series for the 1" drivers and the 299 series for the 1.4" drivers). Remember that the Altec speakers are between 3 and 8 dB more efficient than the bulk of today's speakers (depending on if it is an A-7/A-5 or A-4). If the theatre has A-5s or A-4s then they definately are digital capable. Heck the bulk of the new 3-way systems are practically A-5 knock offs with dedicated bass drivers for the low frequency. Check out the new EAW 3-way system and compare it to the Altec A-5C/MRII594A...the "Asymetrical" mid-range horn has been a feature of the Altec A7/A5 since almost 40 years ago. Add a vented box bass cabinet to one's existing A7/A5 and you got a decent 3-way system though simply adding bass wings will send the A-5/A-7 response on down to 40Hz.

Steve

I'm staying out of this one...

I definately agree with you on that one. There almost needs to be the theatre police to ensure that theatres properly present the medium. The customer has no way of knowing that when they see "Digital sound" (insert your favorite digital sound system for Digital) if it is installed correctly or fully. Certainly a 4.0 or 4.1 digital sound system, all else being equal to a properly installed 5.1 (or 7.1 SDDS) system. But you know, that is true of the sleezy folk that just have the 2:1 screens for "Flat/Scope"

To some degree, that is where THX and their standards do help a consumer...at least the system was installed as it was intended and is capable of playing the soundtrack as it was mixed.

But then again, should theatres be allowed to run in mono nowadays? When was the last Hollywood film released in mono (ok Woody Allen still supports the format, but even he goes for SR and now digital to get a good mono track)...in a sense every mono theatre is not presenting the soundtrack properly either and you can bet they don't even have the proper noise reduction to play the film in mono so it sounds decent.

Nowadays, I'll take a digital 4.0 or 4.1 sound system over a crappy out-of-date mono sound system (one has to pick their battles, I guess).

Also, another thing to cosider is if the theatre can physically take a subwoofer without major sound leakage. If your walls are not built to STC 75 or better there will be significant bass transfer if you have a good subwoofer system (goes down to 20-25Hz). Which brings up another issue...is any sub good enough...there are some of these "econosubs" that use cheaper drivers and only go down to 38Hz or so...I mean most stage channels go down to 40Hz...the sub in these theatres really is just a dedicated speaker that cant play high frequencies rather than a true subwoofer. The only thing good about them is that they don't play though walls as well!

Steve

Well, I had coffee with a highly respected theater engineer this evening, and we discussed the CP-50 and a few other things. When I mentioned that some people thought the CP-50 was better then the CP-55 for conversion for digital, he looked at me like I was nuts for even thinking this. He almost had a heart attack when I told him that some thought the CP-50 equipped with old orginal cards would out perform the CP-55 or a CP-65.

Can you explain why the CAT 108 in the CP-50 is better than the CAT 240 in the CP-55? Why is the CAT 22 in the CP-50 better than the CAT 222 in the CP-55 and CP-65? Why is the CAT 150 in the CP-50 (if it even has it) better than the CAT 150E or later in the CP-55? Why did Dolby have to use a heavier power supply in the CP-55 when they added a few other cards? (I forgot the cat numbers.) I would certainly like to know the answers to these questions for my knowledge base.

The butchering of the backboard to accomodate split surrounds in the CP-50 is for the birds. The CP-55 is much easier. The CP-55 only took about 10 minutes if I recall. Been about 5 or 6 years ago since I did one.

The reliability of the CP-55's I had were great! From the day I installed them, including adapting them for the SRD, SRA, and DTS, the reliability was phenominal. I had one failure, and it was minor. The CP-50, well, about once a month I had to re-seat the cards and tend to other failures as well.

Can you explain why the superior CAT 108 has a 150 degree phase roll built into it that is obvoious when the card is swept? This is what I am told, by the way. I have heard it was a fudge factor that had to be thrown in to make the slit loss compensation work better. If this is true, no wonder the CP-50 has such a horrible phasing problem. I have heard engineers complain about it from time to time.

It is my understanding the CAT 240 in the CP-55 didn't need that phase roll, and that would explain why the 240 sounds cleaner than the 108. The CP-50 backplane boards had hum problems, too. I have changed out many defective ones when the CP-50 hit the market.

Since the CP-50 is over 21 years old, most of the edge connectors are getting goofy now, and sometimes the cards have to be re-seated on a monthly basis. Also, the mechanical switch cards are worn out, and probably the capacitors are starting to get flakey after 21 years in service in most of the modules, including the power supply.

If someone offered to sell me a CP-50 for $100.00, I would turn it down. As a matter of fact, I gave a CP-50 away about a year ago. The switch card was shot, and so was the CAT 22. One of the CAT 64's had a problem, also. I don't know what the replacement cards would have cost, and I was not about to find out, either. The POS has served its purpose.

It may be an opinion thing, but I have to respect the opinions of Dolby. They designed the damn thing, and I would presume they know how it works.

I respect the opinions of those who swear by the CP-50. I swear at the CP-50's now, because they just too obsolete to fool with.

If the CP-50 was outfitted with the latest hardware and if time means nothing to those who want to fool with them and adapt them for digital applications, that's fine. They can have a ball doing it.

I can get a full decked out CP-55 for $1500.00 with the SRA-5 card. In fact, I just purchased it Monday of this week.

Several weeks ago, I turned down a CP-50 for 200 bucks. I could buy a basic CP-55 for 500 with the latest cards except it did not have the SA provision.

Does the CP-50 come equipped with a CAT 241? Will the CP50 handle a CAT 441? I am not sure, but I don't think so. I have not kept up on those old boat anchors. The last cover on any CP55 I opened was 4 years ago. It was a span of 9 years since I even looked inside a CP-50, and that was when I peeled the POS off the wall about a year ago and passed it on to the grab bag.

For those who still want to convert their CP-50, please do. I wish you fair winds and calm seas. Before you do, make sure your pockets are very deep. You will need every penny that may be in them.

But, I would still not spend the time of day to convert one.

As I have mentioned, I side with Dolby on this one.

Paul

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Here is a list of accesories you need for a DTS-6D (3 drives) to a CP50:

Power cord.
D435 Timecode cable (you pick length, standard is 30 feet long, if
change-over, be sure to specify that to get the correct
configuration).
2503 0014 00 Analog Output cable.
D567-01 Audio Interface Board.
D711 Interface cable for D567 board.

Best pricing is obtained from a DTS dealer. Our dealers are posted on our web site at www.dtsonline.com under 'cinema'.

All cinema product manuals are posted on our web site techcenter. Click on 'cinema' and then 'techcenter'. Registration is free and, once registered, you receive and instant password and have instant access to the site. Manual may be viewed, downloaded, or printed.

Please let me know if you have more questions.

So why are you (or your bosses, I understand it's not all down to you) advertising DTS sound if you were not equipped to provide the necessary standard in the first place?

In the UK, we have a law called the "Consumer Protection Act" which stops companies advertising or selling a product they cannot provide, or giving a promise they cannot substantiate. I'm sure there will be an equivalent law where you are.

Well first, who cares what some technician, well respected or not, thinks about a CP-50 vs CP-55 for digital...it is just yet another opinion on the case

">>He almost had a heart attack when I told him that some thought the CP-50 equipped with old orginal cards would out perform the CP-55 or a CP-65."<<

I just had to quote that one...since I don't believe you will ever find me saying that the "old original cards" (meaning the first generation cards used in the CP-50) would out perform a CP-55 or CP-65. Get your story straight before you spout it off to others to form an opinion.

Can you explain why the CAT 108 in the CP-50 is better than the CAT 240 in the CP-55?

The Cat. 240 does not set up as flat as the Cat. 108...it has a progressive dropping of level as one goes up in frequency...this isn't often noticed on an LED based analyzer but one with a more continious level will show it off. Furthermore, the Cat. 108C is yet newer than the Cat. 240 and better matches the reverse-scan and narrow slits.

>>"Why is the CAT 22 in the CP-50 better than the CAT 222 in the CP-55 and CP-65?"<<

The Cat 22 is THE reference card for Dolby-A. The Cat. 222 only mimicks the circuit. But then again, that is Dolby-A, not really an issue anymore with the digital discussion.

>>"Why is the CAT 150 in the CP-50 (if it even has it) better than the CAT 150E or later in the CP-55? "<<

What a bizzare question...the CP-55 was issued with a Cat. 150C not the Cat. 150E (and I believe ended with the Cat. 150D). The CP-50 ended with the Cat. 150B...an LEDless Cat. 150 but on par with the Cat. 150C...I don't think the Cat. 150C had any preformance improvment. The Cat. 150D might have but it had significant digital noise on it from the delay board...they had to put a sheet between the two layers to minimize it. Naturally both the CP-50 and CP-55 can be upgraded to Cat. 150E (or 150F) but for either unit, they would have been an upgrade, not original equipment.

>>"Why did Dolby have to use a heavier power supply in the CP-55 when
they added a few other cards? (I forgot the cat numbers.)"<<

The CP-55 only ever had the Cat. 249 regulator card and the Cat. 250 power supply module. The CP-55's power regulator board seems to have been just barely able to handle it's current demands. It often overheated. The Cat 249 also used some parts that became obsolete...hence it is not a repairable item now but is replaced with the superior Cat. 249A (standard on the CP-65). The Cat. 249A is distinguished by the large protruding capacitors sticking trough the metal cover...precluding from using the Cat. 249 Spare slot.

>>"The butchering of the backboard to accomodate split surrounds in the CP-50 is for the birds. The CP-55 is much easier."<<

Surely you jest! The CP-50 doesn't require any butchering for stereo surrounds per-say...the Rs channel is entirely contained on the Cat. 560. If you add up the number of wires that must be tacked onto the CP-50 for digital it comes to about 11 or so...for the CP-55...10 wires tacked on....

>>"The CP-55 only took about 10 minutes if I recall."<< I'll time you on that one!

>>"Been about 5 or 6 years ago since I did one."<< Perhaps and apparantly NEVER since you did a CP-50 yet you make proclamations on the difficulty of a job you haven't done.

>>"Can you explain why the superior CAT 108 has a 150 degree phase roll built into it that is obvoious when the card is swept?"<<

Never noticed it but since you say the phase change is when it is swept then it is of no consequence...sweep a bunch of circuits in the audio path and you will find phase changes everytime a time-varient device is used (read capacitor or inductor)

>>"If this is true, no wonder the CP-50 has such a horrible phasing problem. I have heard engineers complain about it from time to time."<<

Are you saying that the phase relationship is inconsistant from left to right channel? If so, it would have killed Dolby SVA before it ever got off the ground. (and the phase swept thing would kill any speaker with a crossover since the crossover will have the exact same thing)

>>"It is my understanding the CAT 240 in the CP-55 didn't need that phase roll, and that would explain why the 240 sounds cleaner than the 108."<<

Cleaner? How? Now you are just making things up. Remember, my friend, the mighty CP-200 uses this same Cat. 108 you are picking on. People don't generally point to the CP-200 and say it sounds bad or worse than a CP-55. And also remember that the Cat. 108C is the current version that works as well as the Cat. 240A...the Cat. 240A that replaced the CP-55's Cat. 240

>>"The CP-50 backplane boards had hum problems, too. I have changed out many defective ones when the CP-50 hit the market."<<

Backplanes don't have inherent "hums" in them. Poor solder joints, sure...and believe me the CP-55 and CP-65 (and CP-200 for that matter) have had them too. And now the particularly cheap shot...the CP-55 had many a sound failure due to the bypass relays failing but I don't consider that a CP-55 flaw...just an unhappy circumstance...I bring it up because that is sort of BS you are bringing up. I'll be willing to wager I could have had all of those humming CP-50 backplanes working without replacement. About the only necessary CP-50 backplane replacement would be for an optical transformer failure on the most early of units.

>>"Since the CP-50 is over 21 years old"<<

Some of them are that old...just when do you think the CP-50 went out of production? By your date...you make them all out to be pre-1980...before 1980 about 15% of the films coming out were SVA...also the typical plex was under 10 screens and closer to 3-6 screens with some larger. After 1980 the number of SVA films and screen count grew. So when did the CP-50 go out of production and the CP-55 come in? Anybody? Spring of 1985. Do you want to wager on how many CP-50s were made and installed before 1980 vs after 1980? 1980 was a good year, the CP-200 came out the spring/summer of that year...but I digress.

">>most of the edge connectors are getting goofy now..."<<

This discussion is getting goofy right now.

>>"...The POS has served its purpose."<<

POS? Meaning?

>>"It may be an opinion thing, but I have to respect the opinions of Dolby. They designed the damn thing, and I would presume they know how it works."<<

Oh now here is a big flaw. You respect the opinions of Dolby...WHO? Ray Dolby? Did the same engineers design all of the processors and then proclaim that their old one isn't good anymore (also meaning was never good just sufficed at the time) or more likely a group of people that were not with Dolby before and thus don't have any reason to base their opinion other than "the CP-50? Did we make that? Boy thats old!" Are the engineers at Dolby (and the project managers) that incorporated the Rs channel in the Cat. 560 stupid because they didn't conform to "the opinion?" Were they just radicals? Perhaps when you get right down to it...both the CP50 and the CP-55 are nothing more than a collection of cards that work together and create a signal path that does what one wants or it doesn't. Both work for optical and both can work for digital (with closer difficulty than you seem to realize)

>>"I respect the opinions of those who swear by the CP-50. I swear at the CP-50's now, because they just too obsolete to fool with."<<

Here is another flaw...obsolete...All but the Cat. 109 (meter/filter card) can be replaced with a brand spanking new card. The CAT 109 is repair/exchangable. Obsolete normally denotes non-servicable. Clearly, the CP-50 is not in this category yet.

>>"If the CP-50 was outfitted with the latest hardware and if time means nothing to those who want to fool with them and adapt them for digital applications, that's fine. They can have a ball doing it."<< Since you obviously have never adapted the CP-50 for digital then how can you claim that the modifications are any more time intensive than the CP-55

>>"I can get a full decked out CP-55 for $1500.00 with the SRA-5 card. In fact, I just purchased it Monday of this week."<<

I presume you mean the SRA-5 card frame (with Cat. 280T cards) since the SRA-5 is not a card.

>>"Does the CP-50 come equipped with a CAT 241? Will the CP50 handle a CAT 441? I am not sure, but I don't think so"<<

So now you spout your ignornace of the unit yet again...the Cat. 241 was only used in the CP-55 (and could be used in the CP-65 though never officially offered)...the equivalent was the Cat. 160 for the CP-50 (and the CP-200). If you read my previous posts you would have picked up on that the CP-50 can be upgraded to the Cat. 560 (same thing as the Cat. 441 but taylored the CP-50 and CP-200) so _I think so!"

>>"For those who still want to convert their CP-50, please do. I wish you fair winds and calm seas. Before you do, make sure your pockets are very deep. You will need every penny that may be in them."<< You just don't know what you are talking about since you obviously don't know the unit other than how to "rip the pos off the wall."

>>"As I have mentioned, I side with Dolby on this one."<< Dolby who? Ray Dolby or just some people that work there?

Steve

Amazingly enough...the Altec 802 is not a 9-watt driver..not the AES rating, the Continous program rating nor the peek power rating. Facts just aren't a big thing with you eh? What does the CP-50 have to do with popping a driver in the first place? But then again, I'll bet you aren't too big on Altec either...I mean that big bad old obsolete stuff and all. Oh wait, it is still servicable too so I guess it isn't obsolete after all but it sure is old...must be inferior.

Steve