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50EH5 record player conversion?

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  • 50EH5 record player conversion?

    I've just come from a local auction where I bought an old tube record player. I thought I might make a small guitar amp out of it. It has one 12ax7 and two 50EH5 tubes (stereo)
    Is this a project that might yield good results, or should I just save the 12ax7 and junk the rest?
    I only paid $2.00 for it so I would be okay with doing that.
    What do you think?
    Vote like your future depends on it.

  • #2
    I'm thinking that thing's got no power transformer? The tuge heaters run right off the AC line, alkng with everything else. You'll want a tranny even if only for safety, so there's most of the expense... But for 2 bucks you got a chassis & 12ax7? Not bad... now it's a question of time. And is there an OT? Personally I'd keep it & wait til I found enough scrounged parts to make it safe, but that's just me.

    Justin
    "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
    "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

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    • #3
      No I don't see a PT. What could I scrounge one from. I'm at the Good Will store at least once a week, and I'd rather "find" a used PT than buy a new one.
      Vote like your future depends on it.

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      • #4
        Well, there's a pretty good chance that anything else you find will have the trannies, chassis, etc. already included. Old organs, PAs, etc. Check to make sure you couldn't sell it for more than you paid for it first before gutting it, and remember - some people collect these thingz! Otherwise, the only time I picked something up and couldn't use the chassis was an old projector. The chassis was too thin & had too many holes amd slots in it for a guitar amp and was laid out in very bizarre angles. But the trannies and tubes were perfect for a little Vox/Matchless style amp, so I kept them. Really it's a combo of dumb luck and a good eye, and friends who will shop for you. Happy hunting!

        Justin
        "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
        "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
        "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

        Comment


        • #5
          I was hoping I could just make the phono cart. input into a guitar input and be done.(HAHA) I did try that this morning. The tone arm has rca jacks under it, so I used some adapters and hooked it up. got lots of hum and distortion (some guitar sound too).
          So with no PT, there is no high dc voltage? Can you explain what the safety issue is?
          Vote like your future depends on it.

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          • #6
            Originally posted by dmartn149 View Post
            I was hoping I could just make the phono cart. input into a guitar input and be done.(HAHA) I did try that this morning. The tone arm has rca jacks under it, so I used some adapters and hooked it up. got lots of hum and distortion (some guitar sound too).
            So with no PT, there is no high dc voltage? Can you explain what the safety issue is?
            Look at the numbers on the tubes. The 12 and the 50s are the heater voltages. 12+50+50=112vac which was about the line voltage when the unit was made. So the filaments are wired in series directly off of the line. The hi voltage is probably using a voltage doubler or triplet circuit derived from the line voltage as well. 115x2=230vac or 115x3=345vac. The danger comes because there is no transformer isolation, these voltages are referenced to chassis ground, and a modern earth ground cannot be installed. As a record player this "hot" chassis is not easily exposed even though this arrangement is no longer legal to manufacture. If you connect a guitar to it though, the hot chassis ground reference is connected to your strings. If you touch and earth ground or reverse ground and the strings at the same time you could get a lethal current across your chest.

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            • #7
              Okay, I won't plug it in again until I understand it better, and make it into somthing safe.
              Thanks for the advice
              Vote like your future depends on it.

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