Tube "Filament Rattle"?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by doveman, Mar 1, 2008.

  1. doveman

    doveman Member

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    I've been pretty lucky with microphonic tubes ... not having problems.

    One of the 6V6 power tubes I have has always had this very slight oscillation noise. Like popcorn popping way off in the distance. It's consistent (always there) and you notice it when the quitar is off or you are about to turn the amp off.

    If you touch the outside of the tube it stops. It's not really microphonic in that it does not seem to pick up a signal from amp vibration. It's just creating this tiny little rattle underneath the rest of the sound.

    The tubes seem sound fine ... those little high temp rubber bands wrapped around it would probably stop the noise ... since touching it stops the rattle.

    Other than replacing perfectly good tubes, any other ideas?
     
  2. GearHeadFred

    GearHeadFred Member

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    Is it a JJ by chance? I have had several JJ 6V6s with this issue.
     
  3. doveman

    doveman Member

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    yep ... it's a JJ
     
  4. doveman

    doveman Member

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    This is my first JJ tube. As I said, I've been pretty lucky with tubes. Looks like I need to replace this set. If you had this issue with many 6V6s from JJ, did you replace with another make of 6V6 tubes?

    Anybody ahead of the crowd for good 6V6s?
     
  5. Groovey Records

    Groovey Records Member

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    Your should always have a spare set of power tubes on hand so that's a good idea to replace them. But if theirjust on the edge of sensitivity using a stabilizer can extend their life significantly. The Neoprene High Temp O rings work great.

    For Pre-Amp tubes I like these Halo's. They don't muffle the natural vibrations and harmonics of the tone shapers but tighten them up just enough to be stable. http://herbiesaudiolab.home.att.net/halo.htm

    [​IMG]

    On the 6V6's these Mil spec'ed Brimar's are the most stable and best quality available
    http://kcanostubes.com/content/estore_details.asp?product=224

    EnJoY ThE MuSiC
    GrooVey Records
     
  6. GearHeadFred

    GearHeadFred Member

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    This was a brand new pair of JJ 6V6s - I complained to the reseller.. and he sent me another tube to replace the one that rattled.. But within a week, all three were rattling!

    I eventually went back to 6L6s.. and I have never had a problem with the JJ 6L6 in many sets of them in many amps. Seems specific to the JJ 6V6.
     
  7. doveman

    doveman Member

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    I wired the D'Lite as a 6V6/22w and 6L6/33w with a toggle switch. So with this problem I pulled a couple of my Boogie's 6L6 tubes and gave it a go.

    Pretty nice ... had not tried the 6L6s yet ... sweet. This little D'Lite amp is just too cool. I might get another set of 6L6s in the meantime to replace the Boogie set and store the 6V6s for a bit.

    EDIT: Just on the off chance that it would help, I put the 6V6s back in BUT swapped the sockets. The small noise seems to have vanished. I must be living right!

    :)
     

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