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Dumb it down a little more (QSC speakon)

Discussion in 'Amps and Cabs [BG]' started by brich74, Nov 3, 2005.

  1. brich74

    brich74 Guest

    I have switched from a small combo to a pre/power/cab setup. I now have all the pieces but they aren't playing nice. Please help me wire my speakon for bridged mono with my RMX850. I have the opened up the connectors and this is what I see:

    Green Wire 2-
    Black Wire +1
    White Wire -1
    Red Wire 2+

    I have gathered thru searching that I need to rewire the amp end of the cable. Please tell me what wires go where. I know this has been covered a bunch, but I am pretty dense.

  2. tadawson


    Aug 24, 2005
    Lewisville, TX
    For most bridged application, it is a two wire cable. The amp end will wire from 1+ to 2+, and the speaker end to 1+ and 1-.

    - Tim
  3. brich74

    brich74 Guest

    So should I go by a two pole cable and use my 4 pole connectors, or can I use my 4 pole cable? I rewired my 4 pole cable as I thought I should but it's not working properly.
  4. fretlessrock

    fretlessrock Supporting Member

    Aug 8, 2002
    Bridged mode uses 2 conductors only. So the previous post is all the info you need. You have to identify each end of the cable because they are not wired the same.

    The RMX manual (get it in pdf format from http://qscaudio.com if you don't have it) is a good source for this info.

    If you have all speakon you have this setup:

    AMP +1 ------------ +1 CAB (tip on 1/4" plug)
    AMP +2 ------------ -1 CAB (sleeve on 1/4" plug)

    4 ohm minimum in bridged mode
  5. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    Okay...Amp end of the cable... Black to +1, white to +2. Disconnect all remaining wires. Cab end. Black to +1, white to -1. Disconnect all remaing wires. Voila.
  6. If the amp has a seperate speakon connector for bridged output, it is quite possibly wired +1, -1.

    I was thinking about this.... I made the same assumption you guys are making initially... then I thought of this.
    +1, +2 wiring is equivalent to what you do with binding posts to bridge vs running stereo, carrying that idea into the 4 pole conductor and assuming its wired the same is natural, but I think is not valid.

    Only reason to wire it that way would be so you can use a 4conductor speakon plug at the amp to plug in both stereo speakers, or a differently wired speakon (+1, +2) to connect one cab in bridged mode, both using the same jack on the amp. Makes sense for bridge mode. But you have a speakon plug at the amp that splits into 2 long cords going to opposite ends of the stage for a stereo setup? How likely is that? Is that really an improvement over just 2 seperate speakon to speakon cables wired normally to handle stereo. And the same jack could be used wired +1, +2 to connect the bridged output to one cab.

    I know my Mo'Bass has a 2 conductor speakon jack wired normally (+1, -1) for the bridged output. And I hear Bag End amps have the output speakon jack wired goofy, require non-standard speakon wiring at the amp end, not the speaker end.

    Where the 4 conductor makes sense is a short split at the amp end, +1, -1 for lows, +2, -2 for highs in a biamp system. So the long cable run with 4 conductors ends at the same speaker. THen you can't mix up the highs and lows accidentally. But it makes less sense with a 4 conductor cable at the amp, which immediately splits to go to a stereo pair of speakers on both sides of the stage....

    And also if you have +1, +2 wiring at one end of the cable, +1, -1 wiring at the other, now you have to know which end goes into the amp, and which goes into the speaker, and since they're physically identical, how do you tell them apart?

    I would not assume anything here, get a copy of the owners manual and verify.
  7. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    It's a QSC RMX series. +1 +2 at the amp end, +1 -1 at the cab end. No need to confuse him with all this gobbledygook. You SURE you aren't a politician, randy? ;)
  8. brich74

    brich74 Guest

    Thanks for the info. I was using the red and black as positive negative and leaving the green and white attached and overall just making things more difficult than they needed to be. Now I'm excited to get home and see what my new rig can do! Much appreciated.
  9. No, its just that there are different standards for wiring these, if you guys are looking at manufacturers documentation, you're fine. If you're speculating, or assuming, its not likely to be correct.

    I know bag end is wired one way at the amp, my Mo'Bass is wired standard for bridged mode, providing a 2 conductor jack specifically for that (so only way to wire it is +1, -1... :D )

    That +1, +2 wiring really sucks, by the way, how do you tell which end is the amp end, which is the cab end... you have to mark them specifically? :rollno: Are they just using 1 speakon connector for both bridged output and stereo output? That would necessitate the +1, +2 wiring. Otherwise no reason to wire a seperate bridged amp output differently....

    The purpose of the 4 conductor neutrik connectors is to make the amp hookup MORE foolproof, you just plug in and don't worry. having to worry about which cable is wired how, AND which end has to go where.... :rollno:
  10. Dan1099

    Dan1099 Dumbing My Process Down

    Aug 7, 2004
    This is pretty standard wiring for any 2 channel poweramp with speakons. I realize it is different for many bass heads. For QSC's RMX and PLX series amps, there are two connectors on the back of the amp... one for each stereo channel. The "channel 1" speakon also doubles as the bride mono speakon output.
  11. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Yep. If you use the amp for biamping the 4 pole connector is very handy as well, since you only need one 4 conductor cable to your cab. Personally, I just use a banana to Speakon cable when I run bridged. Then what you see is what you get, no worries about which end is which. To anwer your question Randy, yes you need to label the respective cable ends.
  12. is this for all cabs?
    i called QSC and they told me you had to check the seaker to see how its wired.
    i would be running plx bridged into a schro 1212.

  13. fretlessrock

    fretlessrock Supporting Member

    Aug 8, 2002
    The only thing that could screw you up is that you would have a phase problem if you were running two cabs and one of them was wired with the "-" terminal wired to the tip/+1 side and the other was wired with the "+" terminal wired to the tip/+1 side. The second way is the typical way to wire a cab. If it was only one cab it isn't going to make any difference. Either way you aren't going to blow anything up.
  14. 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
    On QSC RMX, PLX, and PL2 amps, there are two Speakon output connectors. The upper Speakon has channel 1's output on 1+ and 1- and channel 2's on 2+ and 2-. The lower Speakon output has channel 2's output on 1+ and 1-.

    Therefore, if you have two 2-conductor cables with Speakons wired to 1+ and 1-, you can use one for channel 1 and one for channel 2. That's great for stereo or parallel mono. For bridged, use a 2-conductor cable with the Speakon wired to 1+ and 2+, and plug it into the upper output connector. Or for stereo or parallel-mono operation with one 4-conductor cable, wire the conductors for channel 1 to 1+ and 1-, and for channel 2 to 2+ and 2-. That's about the maximum amount of versatility you can get from that sort of configuration.