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QSC PLX 1804 Rattle!!!

Discussion in 'Amps and Cabs [BG]' started by martybernal, Jan 2, 2007.

  1. While sitting on top of my 2 X 12 bass cabinet bare, my QSC 1804 is rattling really bad. The Eb note seems to create the rattle the worse, but is pretty much always there just not as loud. I am sending it back to QSC for evaluation and repair. Just curious if anyone has had a similiar experience and what was the solution. Thanks. Marty
  2. jokerjkny


    Jan 19, 2002
    NY / NJ / PHL

    no rattling here. but yea, i'm sure the QSC guys can totally hook you up.
  3. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Not with my 1804, but I've seen the original series PLX amps do this in one or two cases (and not so in many other cases). It was the cardboard "hood" surrounding the heatsinks, and a small, strategically placed shim cured it instantly and permanently.
  4. Yup with 2402. It's the cardboard baffle used for air ducting.
  5. Stevem627


    Nov 30, 2005
    Corinth, TX
    I had the same problem with my Crown 602 -- exact same reason -- shield rattled.
  6. Steve


    Aug 10, 2001
    yeah, they're not vibration hardened at all. I had to spend some quality time with my 2404 before it would shut up.

    The fiber board air duct will rattle against the circuit boards and the circuit board will rattle in their stand off brackets.

    It's a quick and easy fix. a little tape, a little silicone and you're good to go
  7. Nope, mine doesn't have any rattles. If it does start at least I'll know what it is, thanks guys.
  8. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    It would most likely be the air duct over the heat sinks. It's made of fish paper, which is similar to a card stock material but with excellent electrical insulating and moisture repellant properties.

    The vast majority don't seem to rattle, but sometimes one does. Sometimes pressing the creases a little tighter, or a shim, or foam weatherstripping tape, or a little RTV silicone will take care of it. You won't void the warranty doing this unless you somehow mess something up.
  9. fixed my 2404 up fine.

    Bob helped me figure all this out (great guy). Just a note, however, it does seem to be fairly common if you do a TB search in the amps forum (i.e. wonder if the "vast" majority that don't are actually used more in a PA capacity vice bass amplification role).

  10. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    I've owned 4 that I used in bass applications at least some of the time. Only one rattled, and it had a long, scary history before I got it. But sitting on top of a bass cab is undoubtedly gonna show any problem more than sitting in a rack off to the side of a PA.
  11. rok51


    Sep 2, 2002
    Crawfordville, FL
    My 1602 rattled. Added some neoprene strips to the cardboard and that silenced it.

  12. mikeddd


    Nov 12, 2009
    San Antonio, TX
    Wanted to bump this thread to say "Thank you!" :) I received the same answer/fix action from Bob from QSC. My PLX3602 is now buzzzzzratttttle-free! For mine, it was the side of the duct next to the big capacitors. A little hi-temp silicone fixed that right up.

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