Dismiss Notice

Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

Bridged amp/cab speakon wiring question

Discussion in 'Amps and Cabs [BG]' started by cgworkman, Feb 11, 2006.


  1. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    I''ve been running my QSC RMX 2450 bridged into an 8ohm cab for years. However, I just purchased a new SWR Goliath III (8ohm) that has a pair of speakon jacks on the back. According to the manual on my QSC, when bridged the speakon pin +1 goes to the poitive speaker terminal while the +2 speakon pin goes to the negative speaker terminal.

    For this application I'm going to be making my own speakon cables. I understand how the speakon connector should be wired on the amp side - but my question is: How is the speakon jack on the back of the SWR wired? It says nothing in the SWR's manual.

    My understanding is that a standard speakon connector is wired +1/-1 to the +/- speaker terminals respectively. Is this how the SWR's speakon is wired? And if so, would I make the speakon cable going from the amp to the cab as:

    Amp side +1 to Cab side +1

    and

    Amp side +2 to Cab side -1

    ?

    Hope this makes sense. I believe I have it - but wanted to make sure and not blow anything up.

    Thanks in advance.
     
  2. tadawson

    tadawson

    Aug 24, 2005
    Lewisville, TX
    Speaker cabs are wired standard with 1+/1- for either full range input, or biamp-low. The 2+/2- is used for biamp-high.

    - Tim
     
  3. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    I had to re-read what you said a couple of times but I believe you are correct.

    Let me state the hookup another way.

    The amp side of the cable is wired +1,+2.

    The cabinet side of the cable is wired +1,-1.

    I believe you are saying the same thing and also giving a nod to proper polarity wiring (makes no difference with a single cab).

    Just make sure you mark one end of the cable so you know which end goes where!

    :D

    Joe.
     
  4. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    Thanks guys - I appreciate the help.
     
  5. Good point, the cable now has an amp end, and a speaker end. Not reversable. Some amps have seperate speakon jack for bridged, so normal cable can be used.

    Randy
     
  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
    There are some cabinets (PA, anyway) that are wired 2+ and 2- instead of 1+ and 1-, for whatever reason.
     
  7. Its not true that your cable now has an amp end and speaker end. Draw it out to verify for yourselves. If you switch the -1 and +2 leads on one end of the cable, the cable is still symmetric.

    +1____________________________+1
    -1____________________________+2
    +2____________________________-1
    -2____________________________-2


    See, the same.
     
  8. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    Um....wurm,

    there is DEFINITELY an amp end and a cabinet end.

    Re-read the above posts and then ask any questions if you still don't get it.

    :D

    Joe.
     
  9. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    Considering the posts INSIDE the speakon JACK are setup by number - yes, there are two different ends. The +2 will only line up in the +2 slot in the jack.
     
  10. I'll grant you that when you turn the cable around, the negative side of the signal now passes down a different wire, but the +2 pin in the amp is still connected to the -1 pin on the cab.
     
  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
    One thing to keep in mind, though, is that on an amp with a 4-pole Speakon output wired to carry both channels (which is the type we're discussing in this thread), the other two terminals, 1- and 2-, are actually at ground.

    wurmhole proposes a clever arrangement using a 4-conductor cable so that its direction, when used for bridged mono, is irrelevent. This would work with most cabinets, even the vast majority. There are some cabs, though, that have 1+ wired to 2+ and 1- to 2-. I think it might've been a Peavey cabinet that I saw this arrangement in. Using a cable like this would result in shorting the amp channels' outputs to ground, which would be bad for the amp and it would not allow the system to work.

    It's just something to be aware of.
     
  12. Thanks Bob, luckily there are no Peaveys in my arsenal. I was having a really hard time figuring out how to communicate in words that my wiring setup is symmetric, perhaps your credentials will keep me from having to work it out.
     
  13. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    Yup, they did.

    Son of a gun...well shut my mouth...

    I was so focussed on a 2 conductor cable that I only took a quick look at your diagram and then blew it off.

    Sorry man.

    I see what you are saying. Very nifty use of a 4 conductor cable.

    :D

    Joe.
     
  14. cgworkman

    cgworkman

    May 14, 2004
    Ohio
    I'm only using a two conductor - so there would still be an amp side.

    correct?
     
  15. Ah, the source of the initial misunderstanding. With a 2 conductor cable there is a right and wrong way to run it. The only thing that will happen if you hook it wrong is that no sound will come out. Thats no biggie for Solid state amps but is a problem with tube amps.
     
  16. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    Um....yup.

    :bag:

    :D

    Joe.
     
  17. Lowtone:
    Sorry, I hadn't read your last post. Thanks for the discussion, this kind of thinking really makes my time here worth while.:)