I have a 4x12 cab loaded with 8ohm speakers. I'd like to connect two amps to this cab, one amp running into the top two speakers, the other into the bottom two. Basically turn it into two 2x12s in the same cab.

Can I do the following without damaging my gear :

  • Install a new input plate with 2 mono jacks
  • Connect the top 2 speakers in series to the left jack
  • Connect the bottom 2 speakers in series to the right jack
  • Connect each amp's 16 ohm output to the speaker input
  • Turn everything on, make noise.

Is there anything else I need to be aware of before I try this?

2 Answers 2


If you keep the speakers in series to get 16 ohms, that would match the output impedance of an amp with 16 ohm output. Electrically, this should be just fine. You can go higher ohms without hurting anything (8 to 16 ohms).

Oh, EDIT: If the common of both jacks are on the same plate, that might create problems, depending on the amp(s). So best to insulate the jacks from one another.


Yes, it's very feasible. Some considerations.

*In series, two 8 Ohm speakers will have an impedance of 16 Ohms. In parallel, two will be 4 Ohms.

*Plastic sockets on a plastic plate will be less problematic than metal sockets on a metal plate.

*May be better to split the cab vertically - just a thought.

*With two different amps, therefore sounds, it could be an idea to build a baffle between the two pairs of speakers, to stop interference of air pressure between the two lots.

*At the same time, is it worth connecting the speaker in other ways, to give options? Parallel pairs, and/or a switched socket for one amp., going back to original spec., all marked clearly of course! Extra wiring, extra socketry, but extra functions. And maybe future-proof with Speakons?

  • Great - I might experiment with putting one set in series and one in parallel and testing how the different amps sound at 4 or 16 ohms. I might hold off on the other upgrades until I have this working properly :)
    – s d
    Jan 25, 2020 at 19:30

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