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Can a bad tube affect a certain frequency range?

Discussion in 'Amps and Cabs [BG]' started by Edword, Aug 11, 2012.

  1. Edword

    Edword Supporting Member

    Jun 23, 2005
    I've been using my Traynor YBA-3 at practice since '04. As of late, when I play an open A on any of my basses, it sounds weaker than the other strings. At first I thought there was some problem with my one bass, but it's happening with all of them now. There's also an intermittent scratching sound. Not caused by turning a knob, it just comes and goes.

    Does this sound like something that could be fixed by changing preamp tubes? I looked around back, and the power tubes all appear to be working. I guess the other possibility might be caps or something.

    Any ideas? If it's tubes, I'll need to buy some 12AX7s. I can only scrounge up two of them around the house, and the amp needs 3.

  2. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Absolutely it can. At one point, I had a bad power tube in my SVT that only affected the note F# on the D string. All other notes sounded fine, but the F# had tons of static.

    But it doesn't mean that ALL your tubes are bad. Try swapping your 12ax7's out one at a time till you find the culprit. Also, try tapping each tube with a wooden stick while it's on to see if you can find the culprit. Tubes don't all go bad at once, and total retubes are a complete waste of money unless all your tubes are fried.
  3. +1
  4. Clammy


    Nov 3, 2008
    Ottawa, Canada
    Endorsing Artist: Neal Moser Guitars, DR Strings
    Definitely. My Marshall VBA 400 had a bad preamp tube that would make a horrible racket when I played an A note on the E string (fifth fret). If I played the open A string, no problem, if I played an A anywhere else on the neck, no problem, but A on the E = crazy buzzing/distortion. I swapped out each preamp tube until I found the bad one. After that, no problemo!

  5. Edword

    Edword Supporting Member

    Jun 23, 2005
    Thanks guys!

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