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Tube rattle

Discussion in 'Amps and Cabs [BG]' started by superfly, Nov 30, 2004.


  1. superfly

    superfly

    Aug 4, 2004
    Any of you tube amp users get slight rattle from your tubes when playing?
    I get a rattle on certain notes. I guess this is normal for some tubes? And part of the "tube thing"?
    What 6L6 tubes seem to be the best for not rattleing?
     
  2. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Are you talking about rattling caused by your speakers? If so, be sure to place a piece of foam between your amp and speakers to dampen the vibrations, or don't stack your amp on top of your cabs.
     
  3. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    If you mean a "chime" sound through the speakers, that is often output tube rattle.

    Not supposed to happen, but lots of makers don't know the old secrets of making tubes , so it still happens. The 6550 in some versions seems to be bad for that.
     
  4. superfly

    superfly

    Aug 4, 2004
    Actually I mean the power tube(s) rattle a bit sometimes because of vibration from the cabinet. NOT rattle through the speaker.
    Do any particular brands seem to not rattle?
     
  5. What your talking about is VERY bad, and is symptomatic of bad tubes, but microphony (tube "noise") means that the rattle is accompanied by electrical noise. NO tube should audibly rattle, but if you're not hearing any kind of noise through the speakers when they rattle, I'm puzzled. Are you sure it's just not the tube retainers ringing on the glass?
     
  6. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    If it isn't thru the speakers, it could be lots of things, maybe not even the tubes.

    I agree, if the tubes rattle due to looseness inside it is difficlut for them not to make a sound electronically. Only if the whole plate and grid assembly rattles as a unit and knocks against the glass can that happen. If any of the elements move relative to one another, it pretty much HAS to make a sound electronically, because a tube works on electric fields that depend on the geometry of the innards.

    If the whole assembly can move, you will probably see that the mica support plates don't touch the glass. Normally there are some "points" cut into the mica that jam against the glass and hold things steady.

    Tube retainers, especially the spring type, as PBG mentioned, or the whole tube plus contacts rattling in the socket, if there are not any retainers, etc, etc.

    Otherwise, how do you know its tubes? Wires, screws nuts, bolts etc all can rattle. It is notoriously difficult to track down such things by ear only.