Projector amps-RCA 416 and Kalart 75-15

Discussion in 'Tube Audio' started by Tony Cape, Jan 14, 2018.

  1. Tony Cape

    Tony Cape New Member

    Messages:
    19
    Hi, I've just joined and yes I still have lots to learn- I'm trying to locate some issues, I have more than one of each projector and one works great and the other doesn't so that will be helpful in determining the problems. On the kalart one works good and the other one sounds like people talking with their hands over their mouths and not very loud(while watching a movie)- kind of the same thing on the 416(I have 4 of these, one works great and the other three you can hear but not great.
    These amps have the following tubes-(excluding rectifier)
    7025
    12AX7
    6973
    I was going to buy some replacement tubes but it looks like the 7025 and the 12ax7 are being sold as the same tube. Are they close enough I can buy one and sub for the other? I know they have different specs, but I want to make sure I'm buying the actual tube I want and not a "this is the same thing" substitute.
    Oh and by the way if anybody has an actual schematic for an RCA 416 projector I would sure like to buy it.
    Thanks
    Tony
     

     

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  2. s-petersen

    s-petersen Scott Subscriber

    Messages:
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    Location:
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    The 7025 is the low noise version of a 12AX7, they are functionally the same, and can be interchanged.
    Pics of the amps can be helpful, top and bottom.
     
  3. Tony Cape

    Tony Cape New Member

    Messages:
    19
    Here are a few pics of the back side of the projector amp
     

    Attached Files:

  4. maxhifi

    maxhifi AK Subscriber Subscriber

    Messages:
    2,222
    Location:
    Edmonton Alberta Canada
    Hi,

    Are you using these as projectors, or just cannibalizing the amp?.

    The Rca is a very good projector.

    -Max
     
  5. Tony Cape

    Tony Cape New Member

    Messages:
    19
    Not cannibalizing, I have 4 416's and I'm using one for parts(maybe restore that one since I had just replaced the blower wheel when both bulbs burned out if I can find a worse basket case). I really hated to take parts off the one I am using for parts, but there seem to be no parts available and very little documentation of any kind. I'm planning to rectify that situation with youtube videos. I want to get as many working as I can. I also have a 400 type MI-1311 and a MI-1338D. Also a PG-201 that I'm looking for reel arms, they were missing. I love these old projectors. I have one of them nearly 100% with a very loud amp seems very good I am going to use that one to troubleshoot the other 2. I also have 2 Kalart 75-15's I'm restoring too. I'm a novice at old electronics, but I really dig it. I am a self employed commercial refrigeration tech. I don't even care if I sell any of them. The parts machine I was going to remove the amp section so I could try to create some type of schematic. There is zero documentation I can find on any RCA 416 projector or any RCA projector besides the PG201 and a 1949 copy of the 400 series. There has to be something from the 50s or 60s...
     
  6. maxhifi

    maxhifi AK Subscriber Subscriber

    Messages:
    2,222
    Location:
    Edmonton Alberta Canada
    J
    Join the forum at www.16mmfilmtalk.com
    You will find a goldmine of information about projectors and also an excellent buy sell forum for movies.

    I have a restored DeVry and a bunch of films, the guys over there have been a big help.
     
  7. Tony Cape

    Tony Cape New Member

    Messages:
    19
    Thanks, I will have to check it out.
     
  8. maxhifi

    maxhifi AK Subscriber Subscriber

    Messages:
    2,222
    Location:
    Edmonton Alberta Canada
    Getting the amp going is not that bad, but requires basically testing all the tubes and resistors, and replacing the electrolytic and paper capacitors. If it sounds muffled, make sure the film is threaded properly, and that the exciter lamp is good and bright. Optical sound loses all of its high end if anything in the film path is even slightly put of line.

    I have a 400 Sr. in my garage, which has severe water damage. I hoped it would be rebuildable but it isn't, let me know if you need any specific parts, some got spared.

    Bye the way, that PG-201, is really cool! I definitely want one.
     
  9. Tony Cape

    Tony Cape New Member

    Messages:
    19
    That's cool if you'd be willing to sell me a couple parts, maybe I could still repair the one I was using as a parts machine. I will prepare a list. Thanks!
     

     

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  10. CopperWizard

    CopperWizard Well-Known Member

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    Location:
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    Out of curiosity, are those coils being used to hold the tubes straight? because they are on a horizontal plane?
     
  11. maxhifi

    maxhifi AK Subscriber Subscriber

    Messages:
    2,222
    Location:
    Edmonton Alberta Canada
    Those are tube retainers, they're fairly common in portable equipment.

    Sure, let me know whatever you need. Send me a PM though, this forum is very sticky about buy/sell requests, since the marketplace requires a subscription. What kind of movies are you watching?
     
  12. Tony Cape

    Tony Cape New Member

    Messages:
    19
    yes, I did check check them and the tubes are straight. The one 416 that was working good but the amp had a lot of muffling, I decided to start by checking all the tubes and everything checked out except the 7025 which had a burned out filament. I replaced it with the 7025 from my parts machine which I tested both halves first and it tested good. I then fired it up with a short cartoon and it was much better, but still doesn't seem to any where near as loud as my best 416. The 416s I'm noticing has a 7025, a 12AX7 and a 6973 on the front and the two horizontal 6973s on the rear. It seems like all the tubes are interchangeable and replaceable by 12AX7. Not seeing any rectifier tube, must be done another way or I have no clue.
     
  13. Tony Cape

    Tony Cape New Member

    Messages:
    19
    At this point I'm not sure what I want to collect, but I bought a bunch of movies from a guy in Baltimore and I finished watching the movie Gator with Burt Reynolds this past Sunday. I like science fiction, but it looks like alot of them go for big bucks.
    When I started getting into old "electronics" I started with tube radios and they are cool and I have several to fix, and then I thought tube TVs would be more fun, so I started reading alot about that and I have several old tube Tvs to fool with, but in the end, all you do is watch or listen. Projectors and 16mm movies are more fun because there is stuff to do as a projectionist and the projectors and the films require some tinkering sometimes to get things to work and I call it "mechanical television". I have enough hobby material to get into to last me well into my 90s and I'm only 56.

    While on the radio kick I found a craigslist ad and wound up with a complete NRI course along with alot of kits unbuilt, including an unbuilt 25 inch solid state TV kit complete including the tube and all the directions! The guy who gave the stuff to me, yes, I said GAVE for free, is a TV repair man(one of the last in the area) and one of his customers dropped off the stuff a few years ago and asked him to find a home for it. Not sure I will ever get to that, I'd be afraid of screwing it up.
     
  14. maxhifi

    maxhifi AK Subscriber Subscriber

    Messages:
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    Location:
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    Ah I like old TVs too, you have fairly similar interests to me, hobby wise. Craigslist can be dangerous, hey? You're right about 16mm movies being expensive, but they are sure fun. One thing I suggest, strongly, is to use better speakers than the ones which come with a projector. I hook up my projector to a pair of klipsch La Scala on either side of the screen, and it is far better than the single 12, the sound is clear and well defined.
     

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