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How to pull these tubes?

Discussion in 'Tube Audio' started by FauxHall, Dec 7, 2018 at 2:23 AM.

  1. FauxHall

    FauxHall Super Member

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    My system has only two tubes - the pair of 12AX7s in the Pro-Ject Tube Box DS, my stand-alone phono stage.

    I'd love to do some tube rolling on these but I don't know what I've got nor how to pull them out to see. They might be branded as Pro-Ject anyway.

    Question #1 - how do I get these out? I can't seem to get a decent purchase with my fingers.

    Question #2 - what would be good replacements?

    To Pro-Ject's credit, the installed tubes have tube cooler/dampers.
    Tube pull problem.jpg
     

     

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  2. luvvinvinyl

    luvvinvinyl Lily! Staff Member Admin Subscriber

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    Rubber gloves?

    Failing that, it appears the the back plate can be removed after removing two screws. That may get you access to the tubes. Or, check to see if the feet have screws, which may be holding the bottom in place. Suss it out, the best you can, go slowly, and take pics before each step.
     
  3. Dandy

    Dandy Super Member

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    Last edited: Dec 7, 2018 at 6:52 AM
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  4. maxhifi

    maxhifi AK Subscriber Subscriber

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    I'd take the unit apart to expose the board, and then just unplug them. The tube coolers appear to make getting a decent grip from above nearly impossible.

    For 12AX7 in a phono pre the main requirement is low noise. I would therefore suggest old stock Mullard, Telefunken, or Philips tubes.

    For newly made tubes I would say the generic Chinese 12AX7 can be surprisingly good. I don't much like the Russian sovtek/EH 12AX7, and the JJs didn't do it for me either. Some of the newer boutique tubes may be good, I don't know though never tried them.
     
  5. FauxHall

    FauxHall Super Member

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    I think these tubes are just a buffer stage after an op amp. I don't think low noise tubes, like 7025s, are critical.

    Does anyone have a schematic? Not on HiFi Engine.
     
  6. triode17

    triode17 Super Member

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    You should send this question to Pro-Ject.
     

     

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  7. primosounds

    primosounds Powered with pure tube sounds. Subscriber

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    The tube coolers should slip off the top. After that it should be possible to remove the tubes. I saw somewhere a tube removal tool that is like a baby bottle tongs with rubber grips over the metal part to help remove tubes.
     
  8. Lavane

    Lavane AK Subscriber Subscriber

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    Some are rubber, kind of like a tiny toilet plunger.
     
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  9. primosounds

    primosounds Powered with pure tube sounds. Subscriber

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    Also the "Chinese finger puzzle" kind.
     
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  10. FauxHall

    FauxHall Super Member

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    Thanks for all the input. I'll email Pro-Ject for a service manual.
     
  11. Dandy

    Dandy Super Member

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    It's rather poor of Project not to explain this in the user manual.
     

     

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  12. Lavane

    Lavane AK Subscriber Subscriber

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  13. gadget73

    gadget73 junk junkie Subscriber

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    any chance it has a hole through the bottom where you can insert a pen and push it up?
     
  14. FauxHall

    FauxHall Super Member

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    Sorry, but I have no faith in my technician skills so no go on opening up the box. I can take off the tube guard but after that, I pay a pro do dig deeper. I like the fishing line as loop to extract the tubes.

    I'll see if there is a local supplier and if not, I'll order a couple of pairs to roll.
     
  15. Dandy

    Dandy Super Member

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  16. Lavane

    Lavane AK Subscriber Subscriber

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  17. FauxHall

    FauxHall Super Member

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    The box looks like a forging or extrusion. One probably slides out the guts from the back to the front after removing the screws in the bottom but even that looks like it requires the tubes to be pulled first.

    Awaiting the service manual
    ! black box 2.jpg box back.jpg
     
    Last edited: Dec 11, 2018 at 1:17 PM
  18. Dandy

    Dandy Super Member

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    Have you tried pulling out the tube guard out leaving the tubes behind? Then pulling out the tubes, maybe with rubber gloves for extra grip?

    Why do I suspect that the service manual won't tell you how to pull the tubes?...
     
  19. Lavane

    Lavane AK Subscriber Subscriber

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    Two pair of needle nose pliers? Grab a fin on each side of the guard and gently wiggle it up?
     
  20. KlipschFan61

    KlipschFan61 Smooth Jazzer

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    That's a pretty funky setup for sure.
     

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