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Dolby CP 200 diagrams !

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  • Dolby CP 200 diagrams !

    I have my CP200 up and running in the hometeater, and it sounds amazing.
    Problem is I can't find a good diagram where I can read the text, the ones that is floating around on the WWW is in poor quality.
    Does anyone know where to find a diagram one can read ?

  • #2
    Look in the Film-Tech warehouse. Also write to Bay Area Cinema Products. They may be able to help.

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    • #3
      Sounds amazing, ok, well... acoustical on indicator, break before make telephone exchange switches up to 4 times in signal path. Slow 741 circuitry opamps, unbalanced design... Not at all to my liking. Even in 1985 in electronics classes my professor asked: Seriously? Anybody actually builds THIS? And we had to discuss the design flaws in overtime after classes But thats just my 2 cents.
      I can understand, it's a nice looking wall of rackmounts. So if I can help.
      I do own an original printout of the schematic diagrams from the early 1980s somewhere in cabinet in my booth.
      Thats hardcopy, no file, so scanning in good resolution is possible, if there's no other help for you.
      Just let me know.

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      • #4
        Bah...that's just snobbery on your professor's part. The CP200 was designed in the '70s with a debut in early 1980 (The Empire Strikes Back was its big debut). I don't recall any 741s in it. Mostly discrete transistors. The CP200 used as much pre-existing cards as possible...hence the CAT 108, CAT109, CAT150, CAT117 from the CP50; CAT64s from the E2 and the CAT22 from the 360 series (hand drawn traces and all).

        Conversely, when my prof looked at its design and saw the TDA analog muxes...his first thought was "robust" using automotive components will stand up better in harsher environments. And, seriously, how many of them have died? You could move to DG series muxes but one needs to know their market. You are, primarily, playing a high noise source (optical sound or even magnetic) through a sheet of perforated vinyl using speakers designed in the 40s (primarily, when it came out). As with all Dolby products (through the CP750, for sure), the weakest link is its power supply...the PS1 (PS1B). That is one place that I rolled my own mod/upgrade and I have systems out there with switch-mode power supplies inside of the PS1B that significantly lowered the noise of it (no more ripple too) but you have to be careful...it was designed knowing the PS1 had a saggy power rail (12V relays, not 15V). Even the replacement output cards, CAT517 and CAT560 presumed a saggy power rail as they used the +24 and "-14" rails to get a bigger swing. I dial my 15V supplies down to 13V to ensure I'm within the spec of everything.

        Everyone's a critic but the true test is how well they lasted and that, sonically, almost nobody complained about them. I still have CP200s in prominent places handling film sound. However, for digital cinema, I do bring that in further downstream as there is no reason to have that flow through a 40 year old piece of equipment. That said, I think the CP200 will outlast what it feeds.

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