I've just rewired my 4x12 cab to become two 2x12s to accommodate for a new head. One duo of speakers is playing loud and clear, the other side sounds extremely underpowered. One speaker at maybe 60%, the other at maybe 25% of the expected volume (and compared to the other pair).

I've tried this amp through another cab with two 8 ohm inputs and she works fine.

The amp has two 8 ohm outputs, so I'm going from each into my "new" 2x12s (all the same speakers, celestion 16ohm wired in parallel for 8ohms). The "good" pair of speakers is wired to a regular mono phone jack. The "bad" pair is wired to a two-lead Cliff jack that was original to the cab.

The contacts on the "bad" jack all seem to be tight, nothing visibly wrong. I've re-done the wiring once, cleaned up all the connections and triple-checked which wires go where... my only thinking is that maybe I have the poles wrong on my "bad" jack, since I can't find a schematic telling me which lead is which, I'm just going off of the pictures I took before I re-did the wiring (and maybe I've had the poles wrong for years and didn't know it).

Could having my pos/negative incorrectly connected on my Cliff jack cause this problem? Or would I not be getting any sound at all?


PS attached is a picture of the jack, if anyone can tell me with certainty which lead is which and whether or not this could be my issue![enter image description here]1

  • I don't see any wiring there.
    – Simon B
    Jan 21, 2019 at 15:56
  • Polarity is important. Wire the two up, and connect a small battery across the terminals of the jack input. Both cones should jump - either in or out. When in phase, they'll both go the same way. Make sure the battery connects the same way for the other cab, so all speakers are in phase.
    – Tim
    Jan 21, 2019 at 16:25

1 Answer 1


On the jack pictured, Positive (the tip of your cable) is the highest of the two connections, and the Negative (Earth - the body of your cable) is the lower.

Connecting speakers in series will increase resistance, and connecting them in parallel will decrease resistance (as in the following diagrams from https://www.hometoys.com/article/2002/06/series--parallel-speaker-wiring/1775/)

Series Wiring

Parallel Wiring

Your original 4x12 cab probably had series/parallel wiring, as follows. My recommendation is to check your wiring - I think you have an incorrect connection somewhere.

Series/Parallel Wiring

  • Thanks everyone! I'll try switching things around and give it a go!
    – Nick
    Jan 21, 2019 at 19:21

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