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amp connecting question

Discussion in 'Amps and Cabs [BG]' started by steve-o, May 8, 2002.


  1. steve-o

    steve-o Guest

    Apr 17, 2002
    Full Range Input and Output Jacks
    The Bigfoot features three, full range input/output jacks (two standard 1/4" and one banana) wired in parallel. If you are running two speaker enclosures in parallel, connect the speaker cable from your amplifier to the 1/4" jack labeled “IN”, and a second speaker cable from the 1/4" jack labeled “OUT” to the input of the second speaker enclosure.

    you may remember me from the 4 ohms load and a 8ohm load to a 4 ohm head deal.
    well can i run the cabs with this?
    it wires it in parallel so then it will have about a 4 ohm load and be fine?
    please help
     
  2. Johnny BoomBoom

    Johnny BoomBoom Supporting Member

    Jun 8, 2001
    Glasgow, Scotland
    Hmmm - a banana input??? Not sure what you mean.

    On my Trace head I have an XLR output and a 1/4" jack out. I use the XLR cable out and run it to the XLR "IN" on my 4 x 10 cab. I then use a second XLR from the cab "OUT" and run that to the "IN" on my 1 x 15 cab - everything is wired in parallel. Two 8 ohms cabs in parallel providing a total impedance of 4 ohms, which is what the amp is rated for.


    Now, if you're using a 4 ohm cab and an 8 ohm cab your total impedance will be 2.67 ohms if they are in parallel. Therefore if your head is rated for a 2 ohm load this is OK. For a 4 ohm load this would not be OK!

    Does this help??? I'm not 100% clear on what your were really asking, so I've had a stab at answering what I think you're asking!:)
     
  3. steve-o

    steve-o Guest

    Apr 17, 2002
    i have been told the only safe way to run the 4 with the 8 is to wire them in pararell
    maybe it is series.
    that paragraph is from the swr sight for the 212
    on the back of my 410 cab it has two inputs.
    can i wire one input to make run with my 15 cab when i plug that in?
    does this make since?
    any help helps thanks
    steve
     
  4. Johnny BoomBoom

    Johnny BoomBoom Supporting Member

    Jun 8, 2001
    Glasgow, Scotland
    Yeah, to run them in parallel do what it says on the SWR handbook - as I pointed out, that's exactly what I do with my Trace set up.



    Cabinets are usually wired in parallel - to ensure the power gets distributed evenly

    I think really what you need to do is get a head that operates down to 2 ohms, or match the impedance of the cabinets (ie trade the 4 ohm one for an 8 ohm one). To be honest I'm not really the best person to advise you on rewiring cabinet inputs!!!!

    There is the resident tech expert - Joris - who may be able to advise you better than I. You could always PM him!
     
  5. If your head is rated at 4 ohms max you cannot run a 4 ohm cab and an 8 ohm cab in parallel unless you want to smoke your amp. You can solder together a cable that will run those two cabs in series but you will get less wattage out of the head. The banana plug is usually is used if you are bridging a poweramp into the cab. SWR now uses Neutrik connections in place of banana plugs.

    So you can get a head that handles a 2 ohm load as Johnny said. You could sell your 8 ohm cab and buy the Bigfoot or look for another 8 ohm cab in your price range to run in parallel with your current 8 ohm cab.