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Little help please for an SVT-II, (old one, not Pro).

Discussion in 'Amps and Cabs [BG]' started by bassomatic, Nov 8, 2004.

  1. Yesterday at rehearsal was running my SVT-II thru a 410, was sounding great as usual, when this hideous crackling sound started coming out of the cab. It wasn't just when I played, but would also happen if the drummer hit his kick hard. At the sametime, it was still amplifying the signal from my bass.

    I thought I blew a speaker, but took off the cover and they seemed fine, so I figured the tweeter was gone. Not wanting to stop playing I just swapped in an 810, figuring I'de deal with the 410 later. Well the loud crackling was still happening!

    It sounded sort of like lightening striking in a movie.

    Before taking this to a tech, does anyone out there have any ideas about what could be causing this?

    p.s. I checked all my cables, tried bypassing effect pedals going straight in, played another bass, all the external things I could think of.

    Thanks for any help.
  2. Tube going microphonic.
  3. How does that happen, and how can I tell which one it is.
  4. ChenNuts44


    Nov 18, 2001
    Davenport, IA
    Give the side of each tube a light tap with the eraser on a wooden pencil and listen to the resulting output.
  5. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Usually microphonic preamp tubes sound a little "boingy-er" than your description.

    Microphonic power tubes often sound like badly tuned chimes, or clanking metal.

    Could still be microphonics.

    Could also be a loose connection inside. That usually tends to be more "static-like" in sound, like lightning heard over the radio. If so, you'll probably NOT hear it tapping tubes, but you might if you give the whole unit a "thunk" with your hand.
  6. brothernewt

    brothernewt Some people call me the stormtrooper of love...

    Apr 13, 2004
    Happyrock, OR
    I had that problem once with the same amp (older svt-II). It was the input jacks... would crackle when amp was pushed or mic'd drums rattled them. Had 'em resoldered and never had a problem with it again...

  7. Tonight's the first chance I'll have to dink around with it. If I can't locate the prob then I'm taking it to a tech. I just want to be back up and running.

    I'll post the prob and fix when I know it.

    BTW, anyone in the SF bay area with a 410he for sale?
  8. Try setting it on the floor and playing. Shaking at 40hz can't be good for solder joints.