Loose Pin / Tube Socket Prob, Pics

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Little Robert, Jan 25, 2008.


  1. Little Robert

    Little Robert Member

    Messages:
    368
    Joined:
    Dec 2, 2006
    Location:
    Monterey Bay, CA
    Hi, the photo's should show the problem.

    Which is that if the power tubes are tight in sockets, they can still move up and down within the socket. On the rectifier tube a friend installed a spring-steel bear trap to hold it in place and that works.

    Do I need to do the same for the power tube sockets, or is there another solution.

    [​IMG]

    [​IMG]

    Many Thanks for any help!
    Bob
     
  2. lespaul6

    lespaul6 Senior Member

    Messages:
    1,335
    Joined:
    May 6, 2007
    Wow, talk about a strange coincidence! I posted a question similiar to yours just today asking if there was some barrier that acted to prevent the pin from being pulled out of the socket when replacing a tube...seems when I pulled out a power tube today, one of the pins (you pictured) followed with the tube and extended past the socket. When I pushed to tube back in it goes back into place and seems to work fine. Looks like there is a small flange or bend in the shaft that would act as a stop. Mine is probably flat or something, allowing the pin to extend to a greater degree than usual...anyway regarding your question, isnt there usally a little play even when the tubes are tight?
     
  3. rockon1

    rockon1 Member

    Messages:
    11,456
    Joined:
    Aug 12, 2005
    Location:
    Stamford CT
    I had a similar problem with one my amps. I put tube retainers on the sockets. Bob
     
  4. Little Robert

    Little Robert Member

    Messages:
    368
    Joined:
    Dec 2, 2006
    Location:
    Monterey Bay, CA
    Thanks for the replies.
    Here's what Jim from Frenzel amps told me this morning:

    "...movement of the tubes in the sockets is normal. The socket connectors float freely in the ceramic base....but grasp the pins of the tube tightly."

    So it sounds like even when the tube pins are in the socket tightly, there will be a tiny bit of acceptable movement.

    But, for some reason I don't like it.
    Bob
     
  5. Chris Scott

    Chris Scott Member

    Messages:
    6,952
    Joined:
    Sep 1, 2006
    Location:
    Playa Jaco, Costa Rica
    I don't blame you- I don't like it either.

    Fact is that as long as the pins have engaged their respective sockets, all is well electronically. But without something to hold the tube in place, especially with a Fender-style (tubes inverted) amp, it's possible to lose one on occaision. The "bear trap" tube retainers are the best bet, unless it still bugs you, in which case I'd swap out your existing sockets for some Belton Marshall-style ones- tight and sure, they are...
     
  6. 12guitdown

    12guitdown Silver Supporting Member

    Messages:
    2,403
    Joined:
    Mar 11, 2008
    Location:
    between Doheney & Old Man's
    I have the same problem but mine goes a little deeper. All the little flanges are loose and wiggle around, even when the tube is installed. Thus the tube rattles freely as a result. This only happens on one tube socket which just happens to be the EF86 in my vox ac15 Heritage combo. No Bueno. Even though I have tube dampers it's still microphonic. I don't think I can put a tube retainer on it because of the tight configuration within the chassis. I have some silicone, high temp rated at 600 degrees, and I'm wondering if I could put a small bead around all the tabs which will keep them from rattling.

    Do you think this is a good/bad idea?
     
  7. SatelliteAmps

    SatelliteAmps Member

    Messages:
    6,180
    Joined:
    Oct 19, 2007
    Location:
    Normal Heights, Calif
    You can put silicone if you really want to. It really isn't hurting anything though.
     
  8. 12guitdown

    12guitdown Silver Supporting Member

    Messages:
    2,403
    Joined:
    Mar 11, 2008
    Location:
    between Doheney & Old Man's
    Yeah but it will keep the tube from rattling around via sympathetic vibes thus less microphonics. right?
     
  9. RussB

    RussB low rent hobbyist Silver Supporting Member

    Messages:
    10,901
    Joined:
    Jul 3, 2004
    Location:
    connecticustan
    Those (cheap) ceramic sockets can be problematic. I find them to loosen up considerably if you're into tube swapping. SOMETIMES fitting tube retainers can be a biotch with ceramics...
     
  10. hamfist

    hamfist Member

    Messages:
    1,598
    Joined:
    Sep 1, 2006
    Location:
    UK
    The high temp silicone sounds like a good idea to me.
     
  11. 12guitdown

    12guitdown Silver Supporting Member

    Messages:
    2,403
    Joined:
    Mar 11, 2008
    Location:
    between Doheney & Old Man's
    Alright, I'll put a couple dabs around some the looser tabs tonight and give it a run tomorrow.
    More to come.
     
  12. JJman

    JJman Member

    Messages:
    990
    Joined:
    Mar 12, 2006
    Location:
    New Jersey
    I've always noticed this with rectifier sockets since only 4 terminals are used and only wires (no stiff components) go to it. I think the angles of the resistors in the pic don't help to stiffen the pins, not that their angle is "supposed" to do that. I probably would have placed a very small dab of solder at the bottom of the offending pins but high temp silicone sounds like a nice cushion.
     

Share This Page