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Please help me!!

Discussion in 'Amps and Cabs [BG]' started by lucas vigor, Jul 16, 2008.


  1. lucas vigor

    lucas vigor Inactive

    Sep 2, 2004
    Orange County, Ca,
    I am not a bass newb, but I have never been really knowledgeable of the electronic aspects of amps.
    I have an older SWR redhead, and I am experiencing a wierd effect. I hit a note, then shortly after can hear "crackling" interference in the signal.
    I have tried it from different AC outlets, and with a surge strip.

    Do you think it could be:

    The pre-amp tube?
    Speakers are blown?
    My guitar cable?

    The sound is not consistently distorted or crackly. It happens sporadically.
     
  2. shoot-r

    shoot-r

    May 26, 2007
    Illinois
    Lucas, You were right, the very first thing to look at would be to put in a new tube.
     
  3. uaudio

    uaudio

    Apr 11, 2008
    Arizona
    You could eliminate theories 2 and 3 above by playing through the headphone jack and using another cable for an extended time.
     
  4. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    $10 it's the preamp tube.
     
  5. lucas vigor

    lucas vigor Inactive

    Sep 2, 2004
    Orange County, Ca,
    Because if it was a blown speaker, then the crackling sound would be consistent, and all the time, right?

    Next question: How hard is it to replace the tube in an SWR redhead? Are we talking about taking the thing apart to get to it?
     
  6. Jaco who?

    Jaco who?

    May 20, 2008
    I'd try a new instrument cable first- I wasn't going to say anything, since I know absolutely nothing about SWR redheads, but I'd think swapping the cable first would be a heck of a lot easier than the tube.
     
  7. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I don't know, but usually it's a simple matter. Consult your manual or look it up at swr.com.

    And yes, it would be consistent if it was the speaker. What you're hearing sounds like a dying tube.
     
  8. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    You would hear crackling even if you weren't playing anything if it was the cable.
     
  9. Jaco who?

    Jaco who?

    May 20, 2008
    I don't move around much when I'm not playing anything, but whatever, man. Just trying to suggest the simpler fix first.
     
  10. lucas vigor

    lucas vigor Inactive

    Sep 2, 2004
    Orange County, Ca,
    Thanks guys! Much appreciated!!
     
  11. 48thStreetCustom

    48thStreetCustom

    Nov 30, 2005
    Colorado
    I know this is an old post but I thought I would reply for anyone else having this problem. I took my amp down to my repair guy and and he said he replaced out all the hard solder. Said it was cheaply done at the factory and a flaw in the design. When the speaker vibrates the cab the old hard solders gradually weaken and ground out causing the very bad crackling noise. I'm now electronic wiz, but this is what he told me. Anyway it's fixed now.
     
  12. Primary

    Primary TB Assistant

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