Dave.
 

You might want to consider getting a CP65 (or a CP55, but it will also need the new cards and some backplane modifications) before going digital.

Aaron

 

If all you want is the DTS or digital advertisment ability (plus digital sound, of course) then DTS makes (and includes with a new purchase) an interface board called the "D567". It is simply a relay board that will allow you to inject the DTS signal into the CP-50's signal path. There are minimal modifications to install it. You will have to remove some resistors on the backplane and wire from the DTS board over to the pads where you removed the resistors. Not to worry, the DTS board does have the resistors on it to keep the levels right.

When you are done, you will have a DB25 connector to plug you DTS into and your optical path will funtion as normal.

As Aaron said, you can go for the full upgrade but it is more work. In addition to the DTS board, you could obtain a Dolby Cat. 560 to have stereo surrounds and have the subwoofer controlled from the CP-50's fader (otherwise, the DTS subwoofer is fixed). The Cat. 517 (output fader card) is also a recommended upgrade (regardless) since it will improve your S/N and reduce distortion...but one must modify the CP-50's backplane some more for that card.

We used to make an backplane daughterboard that, once installed, made the whole digital thing a bit more upgrade friendly. By setting the jumpers to what you have installed, you could have the Cat. 560 and/or the Cat. 517. It also boosted the optical level by 3dB if SR cards were inserted. It also provided a hearing assist output (pre-eq, pre-fader). We stopped making them about 6 years ago when those that wanted digital on their CP-50s had them, the rest of the CP-50s were either pulled or moved down to the lesser houses for optical (in some instances upgrading a previously mono house). We have a handful left of raw boards but time is so scarce that we still owe Mark G one board for some time now!

Steve

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

And just where do you come up with that opinion? The CP-50 has the general processing as the CP-65 and is cheaper to upgrade than to outright purchase a CP-65 (or CP-650)...keeping everything in the quality Dolby relm.

Steve

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

For a DTS-6D, if you buy a system from us or one of our dealers, the one price supplies you with the DTS-6D, a reader, and all cables and accessory boards you need to complete the installation. Also includes an installation manual.

Please visit our web site at www.dtsonline.com Look under 'cinema' to see a list of DTS dealers. Choose whichever one appeals to you.

As far as the CP50 goes, normally, all you will get is mono surrounds.

Karen at DTS
khultgren@dtsonline.com
 

One is better off using a CP-55 now, as those things go for about 500 bucks on the market without the SR adapter. The CP-55 is much easier to deal with when it comes to making it cost effective.

Remember, you want to have good quality sound when the digital system defaults. Otherwise, the GIGO method applies.

I think it is financial suicide to spend so much money on the CP-50 to get it up and running for any digital format.

The CP50's are installed in two auditoriums. There will be NO upgrades to it. We have a DTS 6 and a DTS 6-D to install. Since we have the units from surplus storage we are not going to spend any real money. We are interested only in getting them hooked up and that is all. We will run MONO surrounds and NO subwoofer at this time.

SO... We just want to hook the units straight up to the CP-50's and we find this to be worth the time I would spend doing so, as the sound would not be perfect, but much clearer than the optical.

Karen, we purchased the units used from canada but did not come with the cables. What will we need from you to get these hooked up.

Dave

Paul

Now, I'm not bashing anyone; please don't get mad at me. But as I read Dave's post, my interpretation is, ".. anything so we can say we have digital." As an example; without installing any subwoofers, it's really not DTS or Dolby stereo, as a subwoofer is required with those systems. Has anyone given thought to things like; is the db range of the existing amps and speakers enough for the spl levels digital required? And even though advertising with the word "digital" is not contractually defined as it is with Dolby, I feel it's a bit misleading in this case.

It's not the worse misrepresentation I ever saw in theater sound, but just because you can electrically make it work, it's not right either.

Now, Dave is probably caught in the middle; management has stated what they want, and he is charged with delivering it, period.

Sorry to rant, I just feel it's this kind of thing that cheapens the industry. I get the same depressing feeling when I see a mis-mash booth with, like, all different kinds of projectors, sound heads, consoles, sound equipment thrown together.

Paul
 

I would love to upgrade, but cost is not effective at this time. One thing at a time. First install what we have and make it the best that we can. As money flows easier then piece by piece we can install subs, split surrounds, etc.

I feel all of your pain, but cost is cost and with the way things are right now, money is not easy to come by.

Dave
 

D567 interface board for CP-50
D711 Automation cable

I respectfully disagree with you regarding the CP-50 and digital. The CP-55 cetainly is not the better signal path. It's bad enough that digital tracks sometimes drop out, but to announce it with a "SNAP" each time the format card switches the format back and forth is rather bad. Also, the CP-55 is crippled in the SR department. Dolby no longer has the SRA-5 for SR and the Cat. 22SR/A is a poor excuse for SR noise reduction....the CP-50 on the other hand can take the superior Cat. 280T noise reduction and pay less for the pair of them than one Cat 222SR/A. Depending on the Cat. 150 decoder presently in each, the CP-55 may not even get the edge there. The CP-55 may have the edge in the EQ department if the CP-50 does not have Cat. 64Bs but late model CP-50s came with those too!

So what does it take to upgrade the CP-50? For digital, SR is a must as a back up (same with the CP-55). Stereo surrounds should be done but not a must (both Dolby and DTS offer mono-surrounds all the time as well as their Stereo Surrounds) and if the CP-50 is to have stereo surrounds, a mere Cat. 560 upgrade is all that is necessary for both digital subs and stereo surrounds. The CP-55 needs...a Cat. 441 for the same benefits...that is a dead wash on the cost front plus the Cat. 441 also requires back plane modifications (the SR card or outboard frame does as well on the CP-55).

So what's left? The output card on the CP-50? It certainly isn't a requirement for digital though some improvement can be had. Remember the Cat. 117 was used for magnetic on the CP-200 (as well as the Cat. 64s) without everyone proclaiming that the sound was anything but the best. Magnetic has the same potential levels as digital.

Perhaps the optical pre-amp...again, look at the Cat. 108 vs the Cat. 240 on reverse scan readers...the 240 doesn't set up great. The 240A does...So upgrading the preamp to the Cat. 108C is a wash as compared to the upgrade to the Cat. 240A.

In short, the difference in cash outlay of upgrading the CP-50 vs the CP-55 for proper digital is a whole lot closer to each other in cost and labor than you make it out to be. In fact, the CP-50 CAN be made to outperform the CP-55 in just about EVERY respect. That is, you take a CP-50 with a Cat. 108C, Cat. 280T, Cat 109C, Cat. 150E/F, Cat. 64B, Cat 517, Cat. 112 or Cat. 113C and lastly the Cat. 114C will equal or out perform the most tricked out CP-55 in all measurable respects as well as audible.

In just about all cases, it is cheaper to get a CP-50 digital ready than the CP-55 too. Oh and if you are an "art-house" that handles mono still...the Cat. 109C correctly handles the Academy curve whereas the CP-55 has a token adjustable LPF and link for the HPF...I believe both of the CP-55s are first-order though.

Whether or not it is a good choice depends on many factors though...just how old is the CP-50, what generation are the cards...because I would agree to take the first CP-50 off the line with all original cards to get it ready for quality digital...everything would be changed....but if on the other hand, you have a CP-50 that has been kept up all along or was a late model then the jump is much more minute. To dismiss the CP-50 out of hand may be convienient but not always the best decision. Personally, I favor the installation of SR cards and moving them down to the formerly mono houses...it is quick and it impoves the lesser houses while letting the presentation houses receive the latest.

Ken (thought I forgot about you, eh?)....

The Cat. 113C is not essential for the CP-50 to run digital. It is only essential if your automation so dictates and/or an outboard SR noise reduction (like the SRA-5)

Steve

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

And, of course, Dolby Labs never recommended the CP-50 conversion, either. It is just too old, and too many things must be done to make it work - properly.

Paul

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".

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

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

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

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

I'm staying out of this one...

heh heh
 

My point is: Without subwoofers, I feel it's deliberately misleading to advertise that theater as having DTS, Dolby or "digital." If none of those terms appear in ads, then it's a great use of older equipment.
 

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

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

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

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.

Karen at DTS
khultgren@dtsonline.com
 

As far as sound quality of 50 vs 55 vs 65 it all depends on how good the B chain is anyway. You've got to have a pretty decent B chain to tell which processor is in there in the first place. Since there are no really good B chains in theatres in the Salt Lake Area you're pretty well covered. No one will ever know what processor is in there.
Mark Gulbrandsen
 

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.

So I'd watch my step if I were you... You might end up being sued by DTS - you clearly don't match their criteria.
 

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

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

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

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

Whatever wattage rating it is, it is still easily popped. Like I said, I wiped out a few. Of course, you are entitled to your opinion, and I respect that.

Actually, I do like Altec. I have some Altec 1205's in my possession that are equipped with 802 drivers. I use them on sound gigs with the radio station. They sound very good, and they do a good job if I don't hit them too hard on the high end. I have popped one driver in them, too.

As far as your question as what the CP-50 has to do with popping the drivers, page 7-13 of the CP-50 manual will give you an idea. The following is stated on that page:

"Above 8khz, allow the speaker to set the drop-off. CAUTION: Do not try to adjust the 1/3 octave controls 8khz and above."

Unfortunately, years ago I violated that caution ruling issued by Dolby in some theaters, and I lost some 802 drivers in a very short period of time.

My opinion about the CP-50 is still the same. That old unit is not worth spending money on. When they are removed from service, the best place for them is in the trash, or Ebay looking for a fish to buy them.

Does anyone have a spec sheet 802 drivers? I thought that it said 9 watts RMS, but I could be wrong. I am not going to pick the fly specks out of pepper arguing how many watts they are or are not. They worked very well with 25 watt sound systems in the past, but they just can't quite cut the mustard when used in true high power high SPL digital applications.

In an analog enviroment, they will probably be OK as long as the suggestions from the processor's manufacturer are followed when the house EQ is being accomplished.

I considered your last post a little offensive and insulting. I think this is getting a little out of hand, and if you would like to continue this discussion, let's do it via email. I am finished posting in this tread.

Paul

I figured you might take the last post a bit offensive...to the point I ran it by the moderator first. Some of it was tongue in cheek (mostly about the Altec stuff).

My main complaint with your posistion is that it isn't based on facts, just from the hip to the effect of ...it's old, don't bother with it. The other big objection I have is that you are basing your opinion on the effort it takes without having experienced it yourself yet you would have people believe that it is a long time and high-dollar. When compared to the CP-55, those are just simply not true.

On the Altec 802 front...I will get a spec sheet if it has a 34647 8-Ohm diaphragm or the 34852 16-Ohm diaphragm. The driver can take the 909 (Pascalite) series of diaphragms that will more than double it's power handling though without suffering in frequency response or timbre (part numbers 26420 and 26421). Once upon a time, people used the 808 (Symbiotic) driver since it handled double the power but suffered a bit in the extreme HF.

The CP-50 had nothing to do with popping the diaphragms though...only the technicians and exhibitors did and it wasn't even the EQ controls above 8KHz either. The 802 actually had an easier time with high frquencies that other drivers due to their small size...it is the 500Hz crossover frequency that would be more difficult. Also, in the day of the CP-50 and A-7...most theatres were passive crossover and relatively lower power amps...if an amp was over driven (remember the dynamics of an SVA film was greater than that of a Academy Mono film) then the amp could be over driven...any clipping or like distortion would be directed to the HF section of the speaker. The rational behind the not turning up beyond 8KHz is rather simple...with screen loss coming in around 9KHz and the typical A-chain of the day combined with that films were not mixed for above 12KHz...there simply was more noise up their than signal. And you would have to blast this noise through the screen. To this day, most theatre sound systems are bit phoney in the extreme HF since one is still trying to push through the screen...I find many systems sound artificially metallic above 10KHz.

Since you like to look at the book...The figure 7.2.7 shows the completed B-Chain response to the "X" curve ...note that it follows the curve up to 10KHz (but how could that be? we didn't touch above 8KHz...the treble control is the answer) then a fall off above where 12.5KHz looks to be about 4 dB down from the X curve.

But now lets look at the A-chain side's "after" picture on page 7.12, figure 7.2.6...10KHz is 2 dB down and 12.5KHz was a whopping 6dB down....there just wasn't anything up there to tune for but noise. Dolby uses "side-chains" in their EQ (Cat. 64) so by not turing an EQ pot saves one on noise plus you pick up a phase benefit too. The goal has always been, in any EQ, to turn the fewest number of controls. By stating not to turn the controls above 8KHz, one saved the technician from themselves and their flashy new (and way too heavy) analyzer.

Earlier I mentioned that exhibitors are also to blaim for popping of diaphragms...Exhibitors are always ready to believe they can spend less and get the same. The A-7 has its uses but if the room gets too big, then it is down right silly to think it should be able to do every bit as well as a speaker with a larger compression driver...say the A5. Most technicians, especially back then, didn't know how to calculate how much power they needed to handle based on a speaker's specification. One of the really nice things Dolby Labs has done in their "Technical Guidlines" document is to give a simple method of figuring it out without the complicated formulas. I'm pretty sure they even give the formulas too.

The bottom line though really isn't if the 802 can handle the power...but can the 802 handle the power given the room it is in...one can't have the answer without knowing both sides. Going to the 909 series of diaphragms will often put the 802 over the top if it is marginal. And those diaphragms are current production.

As to posting here vs e-mail here is my position on this (or other topics)...

When one states an opinion such as:...I hate the CP-50 and think the CP-55 is just fine.

I have no problem with that...we are all entitled to decide what we like or don't like be they processors, cars or what have you.

However when one proclaims uneducated opinions as facts (something to the effect that modifying a CP-50 takes a lot more time than a CP-55 or will take every penny you have , in public, that is when I may enter a response. Particulalary when the statements are coming from someone that hasn't done the job.

Now if you said something to the effect of "wow that CP-50 took me all day to modify and the CP-55 took me 10 minutes...I'll never do a CP-50 again!" I might have left that alone though I'll still be there with the stop watch on the CP-55 taking 10 minutes (or even the all day CP-50). That would be a personal experience.

Steve

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"Old projectionists never die, they just changeover!"

Paul, I had no intention of allowing an "offensive and insulting" post and I am quite positive that Steve did not either. I think if you will re-read Steve's post again, you will agree that it is not a direct attack on you personally.

Also for the record (if anyone is interested), I would take an unmodified CP50 over an unmodified CP55 any day...if for no other reason than the CP50 will accept SR cards without ANY modification to the processor whatsoever. Of course, the modifications required to upgrade a CP50 are much easier than upgrading a CP55 too. We don't throw out perfectly good projectionists just because of their age. There is no reason to do the same with a perfectly good processor.

Steve

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"Old projectionists never die, they just changeover!"
 

I've got 4 CP-50's kicking around. Refresh my memory again about what those retrofit boards were for that you were making.

There ya go. I am definately going to Purchase a Board from ya. you owe Mark G one. Now if we can convence Ken to buy the last 4 you will be sold out. One reason I think you are seeing a Demand in the CP50 come about again is the Small time operators that still have Mono and Cant afford a Used CP55 or 65, but are getting the %0 dirt cheap or out of Dumpster to upgrade with. That is how the Howard got thiers. If it can be upgraded to Six Channel and will handle an DTS and Dolby Digital input and give me 6 Channels of output, I am more for that as Most of the CP 50 I was around in Corpus never had any problems, bur the 2 CP55's and the 2 CP65's that replaced 2 of the CP50's always had cards going out or needing to be re seated in the chassis. The 55's were the worst. The ones I had at the Padre Staples 6 were a Package deal that Dolby put together in a Wall mount rack that came with a CP1000 Booth Monitor and 4 Slide in Dual Channel power amps, that were smaller versions of the Kelmar Blue Amps. Needless to say the Amps were taken out when SDDS were added to the Auditoriums and 3 QSC1400 took thier place. Still a Full rack as the SDDS units had to sit on the floor below the racks.
 

The 506T (as in CP-50 6-track) was a daughter board we made from 1993 to 1995) that would mount on the rear of the CP-50 (it will fit all vintages) that once the backplane is modified to accept it (takes about an hour on the frist one...about half an hour on the remaining ones) will allow one to upgrade (or downgrade in a pinch) the CP-50 with Dolby's cards without having to fuss over it multiple times.

It's birth was really out of the era when we were putting in roll around racks with DTS and Dolby digital racks. The criteria was...our roll around racks had to handle platter or changeover booths (yes we have a 5-plex and a 16 plex where there there may be either)...the processors we had to accomodate was the the entire Dolby line up...in 1996 we added the CP-500 as well). As such we had to have an interface wtih each type of processor and an interface with each type of digital (There were plans for dealing with SDDS-6 or 8 but thankfully none of ours are in rolling racks)...The nifty thing was no matter what host processor or what digital processor were mating up...the same connectors were used ...one for audio, one for control...we used the AMP circular connectors. The reader (and motor) connectors were broght out to the front panel for quick hook up...

Any way...the 506T was initially designed to accommodate the mobile digital issue and the first one resembled Dolby's Cat. 651 (go and look THAT one up!). It wasn't too fancy...just provided the all familair "JM-11 and JM-22" IDC connectors with some active level matching to provide a 300mV buss level. I think I had the optical surround get a 3dB boost on the first one too to mimick the Cat 441 on the CP-65.

Well then we noticed there should be some other features....

12th revisions later...there were some near misses along the way except the single source switch chip I was going to use got discontinued after prototype.

The 506T turned into the little fix it board for the CP-50.
First off you modify the CP-50's motherboard once and deal with any upgrades as they come.
The Mobile digital input was also a necessary item (the pinout doesn't conform to anyone eles standard on the DB-25 connector..there were reasons it was chosen).
What if you have a permanent digital processor...say a DA-20 but you have a moble DTS for those pesky Universal films (remember when Universal was DTS only...wouldn't want the big film to not play in digital). Therefore it can accomodate up to 3 digital inputs though one I call the pink noise jack (more on that later). So there is a terminal block to connect your DA-20 (pinout matches the CP-65 and can accept fanning strips or bare wire!)...the "JM-21" connector (since the DTS-6D wasn't out yet) but the DTS-6D can work with it since a simple ribbon connector with a DB-25 on one end and a IDC on the other is a direct pin out. So now you can have both digitals in the rack or one in and one out.
What about SR...well we got the connectors out for a quick and easy hook up to an SRA-5, SMART SR1 or USL SRM-10. Furthermore we put in a pair of line amps to bump up the optical level by 3-dB when in SR if the ouboard SR adapter didn't (the SR-1 didn't).
You say you don't want to blow money on an external card cage and would rather just shove some Cat. 280T's in place of the Cat. 22s? No problem...the 506T will sense which card (22 or 280T) is installed and bump up the optical level by 3dB to match the digital level
But wait, there's more! That pesky ADA...we put in a buffered line amp that is pre-fader, pre EQ with a trim pot. Hearing Assist output (47 Ohm output impedance). Center channel is emphasised the surround channels normally don't have their resistors stuffed since what do people that are trying to understand the film want to hear that garbage for? But if you disagree, the surrounds can be their too!
Then I put in a Pink Noise connector...not a standard one though..it uses the AMP MR style connector...it can be used as a third 6-channel input or with a Cat. 85C (or SG-1) with an appropriate adapter cable...it is your pink noise input jack...on you generator...Le is mapped to Subwoofer, Re is mapped to Right Surround, S remains Mono or Left surround...no more pulling and swapping cards.
If you wanted to be on the cheap and you had a Cat. 160 laying around, you could use the mag section of the Cat. 160 for digital subwoofer...though not entirely correct since the mag section has a downward expander...when you could get a proper Cat. 560...move the jumpers and everything is in business! (I'm pretty sure we implemented this feature).
Cat. 117? Cat. 517? No problem, we take either ...just move the jumpers to which card you have installed...the signal routing and capacitor/line amp issue is taken of.
Lastly, when using the Cat. 560 with the Cat. 517...watch out if done the factory way...the surrounds will be out of phase with each other on optical...we take care of that too...everything is in phase...just plug in whatcha got....including a Cat. 560 without a Cat. 517.

We had one accessory for it...the front panel module...two LEDs and a switch. The LEDs indicated "Digital" and "SR"...the switch could force optical sound in case of a digital problem or lock up (the 506T does take its commands from the DA-20 and or DTS in normal mode so it is automatic but what if the DA-20 doesn't drop out when everything sounds like it is under water and TITANIC isn't on the screen sinking?)

Man, you guys got me to think about this thing when it was put to bed almost 6 years ago!

Due to it's low volume, large size and hand builtness...it wasn't cheap...I wanna say it was $425 or $475 List. Again, it was designed and built in a day where an exisiting theatre wanted to be able to move a digital processor about and there was a mixture of processors and digital processors.

Oh and I only ever made a prototype PN cable (which has now turned into a Cat. 85C to Ultra JS series pink noise injector).

Steve

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"Old projectionists never die, they just changeover!"
 

Let it be known that I stand corrected.

Many aplogies to Steve Guttag.

I have to admit I put on my cross-country shoes and waltzed all over my schwantz. Nothing like going to the bathroom in 5 different directions....Ouch! That hurts!

Thanks to all who tried to re-orentiate my thinking.

Paul

Although, I've been told to do stuff I knew was wrong, and if anyone's been a tech for any length of time I'm sure they have, too.

Things like Paul recounting his experience with changing out CP-50 backplanes in mass due to a manufacturing defect under warranty. Also the bulk of Paul's CP-50s fell into the class of pre-1980 so it would have the older cards even side swinging doors and many without even the Cat. 150 (I believe the Cat. 150 was out in 1979...since there is an "S79" document that has it. In Dolby speak...S79 would mean SanFrancisco 1979.)

Cleary, if one lived through that...it would form an opinion. Now if you did a bulk of your work in the 1980s....the CP-50 was pretty much a reliable beast...however the CP-55 was the one with problems en mass...anyone remember the dreded "STC" relays for bypass? To this day we carry around bypass relays to pitch any of those white pieces of crap.

Neither of the above problems are indicative of a design flaw with either CP though...they were both unfortunate circumstances that caused grief to the field guys, like us.

Now as to the signal path of each....many find the CP-50 an easier path to deal with and it's upgrade path is more recent than the CP-55's and thus offers some improvement not offered to the CP-55...the Cat. 517/560 stuff came out in 1992 (at least that is the copyright on the card(s)). The VCAs on the 517/560 are all the dbx (now made by THAT corp) with better channel to channel tracking, lower noise and distortion...but, as Mark said...the movie goer isn't going to notice the difference and I claim they won't notice the shortcomings of the Cat. 117 either.

Next, we discussed the upgrade path for a CP-50 for DTS digital vs the CP-55. Paul asked I recount some for the benefit of others to understand better. After all, when respected people at Dolby say, don't bother...why challenge them? The fact that it is a bit easier to use DTS doesn't encourage Dolby to promote the idea either.

Ok...first...you just want digital....you order your DTS for a CP-50. One has to clip 4 resistors (I think only 4 need to be clipped, not all 7...but they are grouped so clipping a few more doesn't take any more time, really). If one clips one-end, they could be resoldered if needed in the future. Then solder the 8 wires from the D567 board to the solder pads where the resistors are on the CP-50 backplane...where to mount the D567? Simple, DTS has the screw holes that span the Cat. 560 card mounting holes...use some 4-40 hardware and standoffs and you are effectively done for 4.0 or 4.1 digital...no backplane butchering (no traces cut).

The DTS board has the 25-pin D connector for the DTS player and the contol connector to switch the relays on the D567 board. If one doesn't have a Cat. 560 yet, you have mono surrounds...for subwoofer, if you have one you can connect directly to the D567 board..no it won't track the fader this way but for features it will be within 3-dB in most houses since the volume level for most theatre normally floats no more than one number (6-7 or 5-6 depending on tuning).

If you get the Cat. 560, then you can feed the subwoofer with the fader included...there will need to be a few wires soldered to the backplane to route the surround lines, subwoofer line and the contol line. The D567 board has a dry contact to allow the logic switching of the Cat. 560 into digital mode. Overall...it is starting to resemble the appearance of the CP-55 upgraded with the Cat. 441. They are on par in terms of wires and effort at this point with the CP-55's backplane now having one trace cut for the subwoofer line to have a resistor installed.

The Cat. 517 is a bit more involved and some backplane mods are needed to cut out Left and Right signals from going to and from the noise reduction's line amps also there are some series blocking caps that should be jumped out. This one is probably the most time consuming and so far the only point where traces HAVE to be cut.

So one can see there is no real "butchering" of the backplane...some tack soldering to get the wires to the solder pads but the CP-50 and CP-55 are on par with either other in this manner.

For SR...one can conger up the butchering as described in the SRA-5 manual. But since the SRA-5 is gone (and so is Ultras and SMARTs outboard SR cages...Pana's may be coming soon though) but most CP-50 owners are just happy enough to plunck the Cat. 280Ts right in the CP-50 in place of the Cat. 22s...lets face it, all that is coming out right now is in SR so the Cat. 280s can just stay there. No mods are necessary but there is a level problem of 3-dB if used with Dolby Digital since SR is to be boosted 3-dB over A type...but with DTS...one merely has to calibrate the DTS player for 3-dB less and they match once again so no problem in this senerio...for Dolby Digital, you should get a line amp to boost Lt/Rt by 3-dB (or the 506T). Conversely, the CP-55 must have it's Cat. 243 modified by stuffing a couple of diodes (in non standard places) to make format 03 into format 05. The Backplane must then have a wire connected across the back to tell the Cat. 222SR/A switch modes.

Note, at this point the 222SR/A costs more than a pair of Cat. 280s...the Cat. 280s are THE reference SR card by Dolby...the Cat. 222SR/A is a poor imitation using the Dolby-S chip...listening to the HF information, the 222SR/A will sound spitty and be more apt to pump like other SR knockoffs...it may (or may not) be the best SR knockoff but a knockoff none the less. So for the CP-50...SR is not only cheaper but results in a superior SR reproduction and less work upgrading.

In short review...Upgrading the CP-50 is not the horror story Dolby would have one believe and in fact can go smoothly, and quickly to the degree the exhibitor wants. As compared to the CP-55...they are on par for full digital upgrade in time and effort.

Whether or not a CP-50 is a good candidate for upgrade really depends on the unit. If you have one where the edge connectors are flaky...thats it..it's done...but this isn't just an age thing...it is more of an environment thing and oxidation or the batch of edge connectors in the unit and how well they were plated. Also, if you have the cat 110/116 thing...it is also a bit too far back. But if you have a late model one or one that you have more or less kept up over the years..perhaps already has SR or subs...then it IS something to be considered. It is a judgement call that the exhibitor and his trusted service company should discuss between themselves...not an automatic decision either way.

Can I be done with this one now?

Steve

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"Old projectionists never die, they just changeover!"
 

Now, I am off to Idaho Falls, Idaho to yank a DTS and send back to Karen because it died.

Paul
 

...then again....

What's the problem Paul? One nice thing about all the digital systems that are outboard is that they unplug real easy even by the novice...I have done shop repairs for units in distant places by having them ship me the unit.

Steve

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"Old projectionists never die, they just changeover!"
 

I take pride in giving the customers the best value for thier dollar with what I have.

And so you all get it, this place is a DISCOUNT HOUSE. All second run films for a dollar a piece. SO MONEY IS A MAJOR ISSUE!!! I have been given the opportunity to rape our storage and supplies but new purchases are just not easy to make. We are a very busy theater clearing over 12k in sales per week on six screens after just five months of operation, and increasing about 2 percent each week. SO we will make it, but not if I think I can go out and spend thousands of dollars right now.

I love this business, but I can do without the pain. Somebody get me an aspirin cuz my hed hurtz.

Dave

PS, i agree mark, i could probably even build my own damn boards and cards too besides the cables!

The left channel has a buzzing output which is generated within the DTS itself. It is not a 60hz hum, or a ground loop hum. It sounds like hash noise generated from a flourescent light. But it had a "pattern" that sounded like a 30hz repetition rate. I never actually looked at the signal with an oscilloscope.

We had this problem before with several others, and were repaired under warrenty. Someone told me audio board needed upgrading.

Since the theater is almost 400 miles from me, and I don't have the facilities or the knowledge to actually work on them, it is easier for me just to send them in for repair.

Dave, I hope all is well within your family.

Paul

Steve

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"Old projectionists never die, they just changeover!"