can I damage my power amp?

Discussion in 'Amps and Cabs [BG]' started by Fran Diaz, Oct 24, 2003.

  1. Fran Diaz

    Fran Diaz

    Mar 28, 2002
    Santander, Spain
    Hi all,

    I've got a QSC PLX 1602 power amp. The problem is that the fan noise is a little bit annoying (at home only).
    I'm thinking about installing a fan defeat switch.
    My question is can I damage the amp if I do this? My volume at home is very low.

    keep groooovin'
  2. miccheck1516

    miccheck1516 Guest

    Feb 15, 2003
    i dont have that amp, so im making an informed guess.

    If the fan is not on all the time, i.e. it turns itself on and off automatically, then i wouldnt try and do what you describe, if the fan is on at home practising that means that the fan needs to be on, if however, the fan is constantly on, you may be able to do what you said, however you would need to be very careful that the amp dosent get too hot, and you would also want to make sure that you never forget to turn the fan on when playing a gig or practising at high(ish) volumes.
  3. Yes, you can damage the amp if you leave the fan turned off and it really needs to be on to cool the amp.

    I'd say get a small practice amp for home use.

  4. If the fan is on all the time, you risk damaging the amp. There might be parts in the amp that run hot even when idle. BTW the fan probably runs at a low speed at low volume levels and switches to full speed when needed.

    But you really should ask Bob Lee, he works for QSC. Bob, care to chime in?
  5. Chad Michael

    Chad Michael Suspended Supporting Member

    Sep 19, 2001
    Pacific Northwest USA
    I would not recommend modifying the PLX for the same reasons mentioned above.

    Save $100 and buy yourself a used Alesis RA-100 from ebay. Shallow depth chassis, rack mountable ears are detachable to save space, 75w/ch @ 8ohms, 100w/ch @ 4 ohms. Clean sounding, convection - cooled, no fan noise.

  6. monkfill


    Jan 1, 2003
    Kansas City
    I must have a PLX-1602 with the super-quiet fan option. At low volume/power I can barely hear it. The fan is at full speed when I first turn on the power, but it quickly slows down to barely audible. On the other hand, my old SWR 350x had a loud fan compared to the QSC (though it switched itself on and off) but you still couldn't hear it when the band started playing.

    But I agree with the idea that if you're playing quietly enough that the fan noise becomes an issue, get a small combo/practice amp.
  7. metron

    metron Supporting Member

    Sep 12, 2003
    Tube amps are supposed to run hot but solid state amps are not!!! Not recommending you do that.
  8. Scott D

    Scott D

    Apr 21, 2003
    Minneapolis, MN
    uh, the PLX's or any QSC's don't have power tubes....

  9. Schwinn


    Dec 4, 2002
    Sarasota, FL
    Turn up the gain, bury the fan noise, and show your neighbors what your amp can do!!!:bassist:
  10. miccheck1516

    miccheck1516 Guest

    Feb 15, 2003
    Yeh so he i saying that seeing as it does not have tubes, it should be kept cool, i.e. dont remove the fan
  11. notanaggie

    notanaggie Guest

    Sep 30, 2003
    If that is the one I think it is, with the lightweight switching power need the fan.
    Some of those have the fan blowing past the power supply components in a sort of duct, and I don't think it will be happy if you turn off the fan.

    The power supply stuff can get hot fast because it's heatsink is depends on that air.

    But, if its really noisy it might be going fail and they get noisy first. Is it a whine or something else?
  12. Fran Diaz

    Fran Diaz

    Mar 28, 2002
    Santander, Spain
    OK, I'll leave my QSC alone, it's a great amp and still under warranty. I'll try to find a cheap used practice amp or power amp.

    thanks a lot guys.
    keep groooovin'
  13. Bob Lee (QSC)

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

    Jul 3, 2001
    Chester, Connecticut
    Former Technical Communications Developer, QSC Audio
    If you defeat the fan, it could cause the amp to overheat, and you wouldn't have a warranty to help you out with the damage.

    Dust accumulation can make a fan noisier than it should be. Get one of those cans of compressed air used for cleaning computer components. Blow off any accumulated dust from the fan vanes.
  14. Fran Diaz

    Fran Diaz

    Mar 28, 2002
    Santander, Spain
    Thanks a lot for the advice Bob!!!, I'll clean the fan and won't mess around with it.

    keep groooovin'
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