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Help Setting Up My Power Amp

Discussion in 'Amps and Cabs [BG]' started by freshmeat1989, Jan 11, 2005.


  1. I just got a QSC PLX1202, but I dont have a cab yet, but wanted to set the switches so when I do get my cab, I'll be ready to rock. I'm gonna be running in bridged mono at 4 or 8 ohms, and have all the switches set to the right. Is that the right set-up? What should I have the Low Frequency Filter set at? Thanks for your help.

    Oh, and also, I'm running into an old Sunn 16 ohm PA cab, a 1275, which has a 15" speaker. Is this ok? It has parallel inputs, can I plug into either one of those?
     
  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
    Switch 1: Clip limit on
    Switch 2: LF filter on or off, depending on the loudspeaker
    Switch 3: 30 or 50 Hz, depending on the loudspeaker
    Switches 4–6: Stereo
    Switch 7: Bridge mode on
    Switches 8–10: Don't matter

    Plug into either input on the cabinet.
     
  3. Nightbass

    Nightbass

    May 1, 2001
    Seattle, WA
    I would strongly suggest using the LF filter and setting it to 50Hz. Your old Sunn will thank you for it.

    Also remember that the speaker connections at the amp are different for bridged mode than they are for stereo mode, and you will need a Speakon wired for pins 1+ and 1-, or better, use a a banana plug.

    Nightbass
     
  4. 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
    Good advice.

    Typo! That should be 1+ and 2+, at the amplifier end of the cable.
     
  5. I just got a RMX-1450 and run it bridged in mono. I have the settings like this:

    Switch 1: (RT) Clip limit on
    Switch 2: (LT) 50 Hz
    Switch 3: (RT) LF filter on
    Switches (RT) 4 & 5 Parallel
    Switches 6 & 7 (RT) Bridge mode on
    Switches 8–10: Agree that these don't matter in Bridged Mono


    I run 1/4" TRS into the input for Ch. 1 (which is parallel for Ch. 2)
    I run Bannana Clip out of the red posts on the rear. (just be sure that you know which is post (+) and which is (-) on your bannana clip)
     
  6. 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
    The RMX and PLX are not the same. Here's what you should set yours to:

    Switch 1:Clip limit on
    Switch 2: 50 Hz
    Switch 3: LF filter on
    Switches 4 & 5: Stereo
    Switches 6 & 7: Bridge mode on
    Switch 8: LF filter off
    Switch 9: Doesn't matter
    Switch 10: Clip limiter off
     
  7. Nightbass

    Nightbass

    May 1, 2001
    Seattle, WA
    Whew! Thanks Bob, I can't believe I typed that. I owe you one. :)
     
  8. Can I run a PLX1202 at 16 ohms when not in bridge mode?
     
  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
    Yes, because 16 ohms is higher than the minimum per-channel load of 2 ohms.
     
  10. Around how many watts will i get out of it?
     
  11. 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
    About 100 watts, maybe 110 or so.
     
  12. I wont be running Bridge anymore, so now what do I set the switches to, what is parallel.