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wierd clip indication on QSC amp

Discussion in 'Amps and Cabs [BG]' started by Phat Ham, Jan 20, 2003.


  1. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    My buddy recently bought a brand new QSC RMX 1850HD to power a couple of Carvin TR1801 subs. The other night I helped him set the stuff up. I ran the amp bridged mono into both of the subs for a total of 4 ohms impedance. I cranked the amp until the clip lights would flash occassionally. Needless to say there was some thumping going on. Everything seemed fine so I left everything the way it was. Half way through the gig I looked at the amp again, and the clip lights weren't "in sync" any more. The channel 2 signal indicator was working, but the clip light would only come on maybe half the time the channel 1 clip light came on. Everything sounded fine so I didn't think much of it, but is this abnormal?
     
  2. Bob Lee (QSC)

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

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    • Make sure channel 2 is turned all the way down.
    • Make sure the inputs aren't paralleled, unless you actually need it for daisy-chaining.
    • Check your output wiring, especially if you're using the Speakon output on the amp; if your cable is wired to pins 1+ and 1-, then the speaker load is connected only to channel 1, and so it'll clip at a lower voltage than channel 2.
     
  3. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    I'm pretty sure I had the speakers wired correctly. I used the binding posts and used the two + terminals. Same thing as using 1+ and 2+ with speakons right?

    Channel 2 was maxxed, so there's a good chance that's what was causing the problem.

    Can't remember if the inputs were in parallel or not.

    By running the amp with channel 2 maxxed was the amp being damaged?
     
  4. jerry

    jerry Doesn't know BDO Gold Supporting Member

    Dec 13, 1999
    Hawaii
    If you use banana clips make sure you have them both on the same side......usually the side with the tab is the ground.
     
  5. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    The speaker cable that the cabs came with were speakons wired 1+ and 1-. To run bridged mono I had to cut off one of the speakon connectors and just use the bare wire on the binding posts. I connected 1+ to positive channel 1 and 1- to positive channel 2. It definitely sounded like all 1800 watts were going through the subs. I was just worried about the clip indicators.
     
  6. Why didn't you just rewire the connector? My understanding of speakons is that they are easily rewired without needing tools. But, I will say that I do not currently own anything with speakons.
     
  7. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    I couldn't get the connector off. I even snooped around on the internet researching some speakons and apparently the NL4FC (i think) connectors that were being used are made so that they won't come apart once they are assembled.
     
  8. Bob Lee (QSC)

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

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    No, just dial it in the right way before you use it again and things should be fine.
     
  9. Bob Lee (QSC)

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

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    He's running the amp in bridged mono, so he'd have to use the two middle terminals (the red ones).
     
  10. Well...crap that sucks. There goes that ease of use thing huh?
     
  11. rok51

    rok51

    Sep 2, 2002
    Crawfordville, FL
    NL4FCs come apart easily without tools. Just unscrew the strain relief and the whole shootin' match comes out. All you need is a screwdriver for the terminals. You can easily rewire the connector to whatever configuration your amp dictates. The newer FX series has fewer parts, an improved release and is cheaper, to boot.

    Kim
     
  12. :D:D

    Haven't heard that expression in awhile.

    (Oh, and thanks for the Speakon training)

    b