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Thread: New DRRI - Bb Rattle & Resonant Hum??

  1. #1
    Forum Member 1954Gold's Avatar
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    New DRRI - Bb Rattle & Resonant Hum??

    Hi.... got a new DRRI. Love it, but I get some tube rattle or filament shaking on some notes, generally around Bb or thereabouts.

    Particularly funky on the low E at the 6th fret - rattle with rising hum which then fades out. Generally this doesn't start until the tubes warm up. So I am hoping that I just need to re tube.. which I plan anyway. I can see Groove Tubes in there now as 6V6s..

    Any comments will be appreciated!

    Thanks

  2. #2
    Forum Member stratcat55's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    If it's brand new, they should replace the tubes. If they don't, return it.

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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Probably is indeed a tube the way you describe it. Be careful it's not a resonant frequency of the room you're in, though. In my home studio, an F# (middle register) makes my DRRI rattle something fierce sometimes--I can hear the glass of the tubes vibrating.

    Any other room in my house or out at a gig, the F# has so such effect. However, at one club I play in, I can't play a low register F (i.e., first fret, 6th string) without the whole room shaking.

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    Re: New DRRI - Bb Rattle & Resonant Hum??

    the rattle may be a tube, but the hum, how loud are playing when you notice the hum, as these amps are made with for shit tiwan made power supply filters that can not cut it when the amps is cranking, you get all sub tones under your note being played that may sound like a hum untill you listen close!

  5. #5
    Forum Member Don's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    I have the same problem in my basement "studio". Playing certain notes causes the tubes to rattle in a couple of my amps.

    I thought it was a microphonic tube until i noticed a second amp doing it and that when I play in other places they're fine.

  6. #6
    Forum Member 1954Gold's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Thanks for the replies, guys.

    I am in a small room. Sometimes there is line noise, sometimes there isn't. The line noise is not the amp as the same occurs on my solid state. I play at low volume usually at "2", sometimes, "3". When guitar is disconnected from amp, no amp hum at all even on vol 10. When I hit Bb, the rattle will start and then the line noise spikes, resonates for a second, sizzles, and dies. Power tubes are Groove Tubes with Fender logo. I am thinking retube with JJ DRRI kit and getting a bias probe.
    Last edited by 1954Gold; 02-14-2008 at 05:44 AM.

  7. #7
    Forum Member Rickenjangle's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Did you buy the U2 model of the DRRI?



    Just kidding - but the title of the thread brought to mind U2's great concert film...

    Carry on - nothing to see here... ;-)...back to topic at hand...

    "I'm gonna find myself a girl
    that can show me what laughter means
    And we'll fill in the missing colors
    In each other's paint-by-number dreams..."

  8. #8
    Forum Member NTBluesGuitar's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    It's okay, Rickenjangle, I thought the same thing.



    Oh, and I agree with the resonant frequency, too. In my room, a low register C can do it.
    "...pray do not imagine that those who make the noise are the only inhabitants of the field;
    that, of course, they are many in number; or that, after all, they are other than the little,
    shriveled, meagre, hopping, though loud and troublesome, insects of the hour."

    -Edmund Burke

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    Forum Member stratcat55's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Me too Rickenjangle, you are quick.

  10. #10
    Forum Member 1954Gold's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Quote Originally Posted by Rickenjangle View Post
    Did you buy the U2 ...

    Who?

  11. #11
    Forum Member Wilko's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Quote Originally Posted by pc View Post
    In my home studio, an F# (middle register) makes my DRRI rattle something fierce...
    is the room 12 or 24 feet in one direction?

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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Y'know I've never measured. It's my basement studio, definitely bigger than 12 feet in either direction but might be 24' wide. I have it broken up with a thick rug hung from the rafter about a foot from the wall on two of the four sides.

    Wouldn't surprise me if that's the width though. Is that the F# wavelength?

  13. #13
    Forum Member Wilko's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    The wavelength is right about 24 feet for a low F# on a bass, Half that for the next octave up.

    A room's resonant freq. is somewhat related to the size.

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    Re: New DRRI - Bb Rattle & Resonant Hum??

    Science!
    "I haven't slept for ten days...because that would be too long." -- Mitch Hedberg

  15. #15
    Forum Member Wilko's Avatar
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    Re: New DRRI - Bb Rattle & Resonant Hum??

    She blinded me with science!
    And hit me with technology
    'Good heavens Miss Sakamoto - you're beautiful!
    I don't believe it!
    There she goes again!
    She's tidied up and I can't find anything!
    all my tubes and wires
    And careful notes
    And antiquated notions
    but - it's poetry in motion

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