PLD 4.2 detecting shorts when none

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Sun May 03, 2015 10:03 am

  • I just updated the firmware and 1st show this goes into shorted output. running this for tops 4 MRX515 AB CD 4 ohm 4ohm bridged
    it sees them in the middle of the gig as a short. I can't have this happen, had to reboot while the band played. any suggestions. It never did this before firmware update.
    topdj
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  • how should I be configuring this when running 2 Mrx515 on each cable to my amp each is 8 ohm they are connected together so my cable is showing 4 ohm load for each pair of speakers . I been running bridged from the get go, but after firmware update I started getting shorted output warnings muting show on. Right now I run bridged should I use parallel?
    topdj
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  • Hi topdj,

    For a 4Ω load, it night be better to parallel two channels (i.e., AB or CD), rather than bridge them (A+B or C+D). If you need the added voltage swing that you get in bridging, then you can parallel bridge all four channels (AB+CD), which is preset F8.
    Bob Lee
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    Bob Lee
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  • ok I run 2 of the MRX515 on each side over my subs so it will run better in Parallel? AB CD 8+8=4 ohm load per side will I maintain decent volume?
    can I still use the MRX speaker profile when doing so? because it thinks 8 ohms nothing in menu states your connecting the 2 on the same circuit resulting in a 4 ohm load. Is it sending 800 watts to the pairs I'm jumping together?
    topdj
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  • The new firmware is a little more aggressive at detecting loads that could be stressful. This is to reduce the likelihood of amp failures.

    You could also run them separately, one on each amp channel. You would have about 500 watts available for each loudspeaker.

    See if you can get the sound levels you need without amp doing much limiting.
    Bob Lee
    Technical Communications Developer
    QSC, LLC
    Fellow, Audio Engineering Society
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    "If it sounds good, it is good." —Duke Ellington
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    Bob Lee
    QSC Audio Products
     
    Posts: 2518
    Joined: Thu Mar 06, 2003 2:01 am
    Location: Costa Mesa, California


  • so even old school dual subs being run bridged may shut down in middle of events? that's not good you can't hook them up separately they have a single cable 2 wire. I plan on getting a 4.3 and a 4.5 and was gonna run them bridged on a pair of subs each. Bridged is louder or Parallel?
    topdj
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    Posts: 32
    Joined: Sat Oct 11, 2014 2:31 pm


  • topdj wrote:I just updated the firmware and 1st show this goes into shorted output. running this for tops 4 MRX515 AB CD 4 ohm 4ohm bridged
    it sees them in the middle of the gig as a short. I can't have this happen, had to reboot while the band played. any suggestions. It never did this before firmware update.


    How can I do a downgrade of firmware?. :?:
    btu2000
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