Film-Tech Forum ARCHIVE: CP 55 with home cinema amp

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Posted by Jonathan Wood (Member # 4614) on 11-16-2012, 02:37 PM:

Hi everyone, I was wondering if anyone could answer a question I have.
I'm building a portable sound system and have a CP55 processor. Is there any reason I can't connect the Amp outs of the CP into the analogue inputs on the rear of a domestic Sony processor? The Sony manual suggests it's possible to connect an out board processor into these terminals. It would save me having to lug separate power amps around when the Sony is a multichannel amp , I realise I would have to bridge the surrounds as the CP is mono surround. I guess it all comes down to levels , is the output of the CP at line level? I don't know how much the sony would add to the processing , obviously I would like to keep the CP doing most of the work. Any advice gratefully received! Cheers

Posted by Paul Gordon (Member # 3320) on 11-16-2012, 02:40 PM:

Should work fine, just make some cables that that go from your Cp-55 to the sony, so wire to RCA. As long as the amp has the 6 discreet analog inputs it will work.

Posted by Monte L Fullmer (Member # 2797) on 11-18-2012, 01:15 AM:

Depends if the CP55 has the 446 card for 6 channel playback. Otherwise, a CP55 is 4channel only with the default 246 card.

CD55 were a slight upgrade to the CP50 having optical bass amplifier outputs, but still a four channel processor.

Posted by Sam D. Chavez (Member # 1841) on 11-18-2012, 01:32 AM:

Monte,

That is Cat. 441 and 241 just to be clear.

Posted by Monte L Fullmer (Member # 2797) on 11-18-2012, 03:32 AM:

Thx Sam ... serves me right being away from these Dolby units for a good while .. too much digital influences.

Posted by Jonathan Wood (Member # 4614) on 11-18-2012, 04:06 AM:

Thanks Monte, do u know what mV output I should expect at the outputs on the CP55 , hoping it will be somewhere around line level, don't want to damage the cp. Best , jon

Posted by Sam D. Chavez (Member # 1841) on 11-18-2012, 10:13 AM:

Output level is adjustable so you can make as much as 700 mV.

Posted by Jonathan Wood (Member # 4614) on 11-18-2012, 03:42 PM:

Hi Sam, is this done via a pot on which card?
Cheers

Posted by Sam D. Chavez (Member # 1841) on 11-18-2012, 08:55 PM:

There are trim pots for each channel on the 242 card and one for the subwoofer and surrounds on the 241 or 441.

Posted by Jonathan Wood (Member # 4614) on 11-19-2012, 03:30 AM:

Thanks Sam

Posted by Mark Pasquesi (Member # 7208) on 12-01-2012, 07:50 AM:

Sam,

We have the CP-55, and already have SR (I'm not sure which card). We are adding Digital, with a Christie2210/Doremi 2k4. Another cinema is giving us their Doremi d2A. We also have 2 Amps - 2 Fostex AP 3060.

We are wondering if it's best to stick with the CP55 for now (since our 35 projector is only SR), and feed it into a digital processor (the cheapest being the Dolby 750).

After much discussion, our provider wants us to buy a CP 500,
and 3 used amps (2 QSC LMX1450, 1 USA900) for 6000.

This seems a waste of meny to me.

Seems we should test our speakers and amps to see where we have problems - we know we have some : (and replace the basics.

But for new purchases, it seems we should buy for the future -
dolby 750, Datasat AP20, or USL JSD-80 (replacing the cp55) or JSD-100 (60 is not out yet)...

We need a short term solution - we are putting in digital in a week...
and a longer range for quality as we have more money...

Posted by Sam D. Chavez (Member # 1841) on 12-01-2012, 12:31 PM:

The CP500 is almost free for the asking in the USA as the front door display and fader are often problems and there is no support. Not a good long term solution. I would spend some money on some better amps. QSC is my favorite for sure.

The package of 500/amps seem way overpriced to me. Hope I'm not stepping on the toes of anyone I know.

I'd go with 750 or USL JSD100 and hook the 55 to it. Sooner or later the 55 will go away.

Posted by Carsten Kurz (Member # 5396) on 12-01-2012, 01:03 PM:

quote: Mark Pasquesi
After much discussion, our provider wants us to buy a CP 500

You do not BUY a CP500, you either dump it or take it for free to play with it until it goes dead. Stay away from it. It has a lot of issues and is unsupported, and the audio-quality is not nearly that of even earlier analog processors.

Feeding the CP55 into the CP750 analog ins is a cheap AND quality option.

You will not play 35mm that much anyway after you have gone digital.

- Carsten

Posted by Mark Pasquesi (Member # 7208) on 12-02-2012, 06:39 AM:

Sam, Carsten,

Thanks for your very clear input : )

After looking at the forum together,
our team is finally together on this.
Our provider has finally accepted that we will not take the CP 500.
so far, so good.

He is refusing to install the CP 750 - hates it.
Any ideas as to why? any tricks to proper distribution, frequency, etc? Would it be difficult for us to do this on our own?

Since we aready have 2 fostex, should we just take one QSC for 5,1, or go for 2 extra amps and do 7,1?

We know we have a sound problem -
it seems to be the left screen speaker at the least,
but we have yet to test
a) all the speakers
b) the amps (Fostex)
-----------the continuing negotiations-------

He's offering the USL JSd-80 new for 3,900..

I've heard this in 3 other cinemas - good, but trouble with details ... some mixers had me listen to the mix in their studio..
definitely missing punch and detail from 2k-10k...
Is this just a set up issue (the speakers have great horns, so it's not the speakers - the amps are crown)

-------
Since we may eventually get a scaler, he suggested we look at the Christie Ska-3d - at 6,400 chf...
but I've never heard it, nor read reviews...for sound processor and scaler it seems good, but...
too much in one machine?
-----
Thanks again for your advice!!

Posted by Alban Birch (Member # 4121) on 12-03-2012, 12:24 PM:

You could use the Pre-decode outputs on J18 ( 15=R 2=L) ande let your Sony Amp do the decoding or use the outputs before the Cat64 and Fader, to avoid levelissues, these are on J18 aswell ( 4=L 18=C 5=R 17=S ). Levels are 500mV.

Posted by Sam D. Chavez (Member # 1841) on 12-03-2012, 01:12 PM:

You might need a new installer. There are many thousand, perhaps as many as 20,000 750's installed world wide.

The JSD 80 is a good choice too for analog film and digital cinema together. The price quoted seems high though. The JSD 100 and upcoming 60 are both excellent. As Carsten points out film will not be an issue in the future.

I don't care to offer an opinion on the rest of the issues so I'm out.

Posted by Brad Miller (Member # 2) on 12-04-2012, 02:15 AM:

Mark, it sounds like your installer is only interested in selling you what is in his best interest, not yours. He probably makes more profit on the JSD80 than the CP750, and he probably wanted to unload that CP500.

His prices also seem high.

Posted by Mark Pasquesi (Member # 7208) on 12-10-2012, 08:51 PM:

Thanks for the help!!

We dug in and insisted on the JSD-80...
with the 3 QSC's at a bit over 1,000 chf total...
We'll wait on speakers.....
and hang on to our fostex pair in case we ever go for 7,1...
------
Installation finishes Thursday and Friday...
Psyched to hear a SMPTE measured 5,1 in out theater!!!
-------
A few questions on installation -

Any recommendations on the sound tests?
The technician will do an SMPTE -
should we ask for that through each source?
(Bray, DCP, 35 mm, computer card?)

What about for the various treatments, and their 'effects'?
(DOLBY SR 35mm, Dolby surround, THX, DTS?
And untreated DCP 5,1, DCP and BRAY stereo, and Bray and 35mm mono ?

Given that the USL has readily-made presets, and that we could easily make and then load various files depending on the encodage and number of channels, it seems we could do this...
But is this necessary?
-------
--------------
If the building electricity is funky,
even if we have our own electrical panel for the cinema,
should we try to put something in to keep the current more stable?
(This is more for saving our Christie than the JSD-80)..

I thought that some projectionnists had recommended this,
but I can't find the link anymore...
_______________

Thanks again,

Mark