bass cab wiring diagram for 4 speakers

Discussion in 'Amps and Cabs [BG]' started by Geezer69, May 25, 2019.

  1. Geezer69


    May 25, 2019
    i recently saw where a tb member posted he wanted a 4 spk bass cab he could use with two different impedences. im looking for two inputs of 4 ohms each, and one input of 8 ohms in one box.
  2. Wasnex


    Dec 25, 2011
    You need 8 ohm speakers. Make two parallel circuits of two speakers. 8/2=4 ohms. When you connect these two circuits in series you get 2*4=8 ohms.

    Probably the easiest way to achieve what you want would be to make a two input cab and then use a device like a Radial Cab-Link or Palmer Cabinet Merger.

    Cab-Link - Radial Engineering
    CAB M

    I believe this image can be modified to do what you want. I pulled it from here. stereo/mono cab wiring jacks?

    Basically you need to add a second 8 ohm speaker in parallel with Speaker A and Speaker B. This would change the input options to 2 ohms mono, 8 ohms mono, 4 ohms stereo.

    As you can see the switching is fairly complicated to reason through, and you could accidentally short the output of your amps if you forget to put the switch in the correct position.

    I believe this is essentially and equivalent diagram from

    Here's what the jackplate the schematics were derived from looks like. FYI, 1960A uses four 16 ohms drivers connected in series parallel.
    Jack Plate - Marshall, Switchable Stereo/Mono

    Here's another diagram that is exactly what you asked for
    Modify the left diagram by connecting an 8 ohm speaker in parallel with speaker 1 and speaker 2. This will give you exactly what you are asking for, 3 jacks, 4 ohms stereo, or 8 ohms mono.
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  3. Geezer69


    May 25, 2019
    i've since concluded that i'll just get another 4 ohm bass cab to parallel with my existing cab, problem solved!
    Last edited: May 26, 2019
  4. ctmullins

    ctmullins Dominated Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    If your existing cab is also 4 ohm, then you’ll need a 2 ohm capable head, which are not common.
  5. Geezer69


    May 25, 2019
    My amp is a Peavey 210w @ 2ohms slave amp with 2 -1/4" parallel output jack's. Minimum load 2 ohms is stated on the back.
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