i bought an ampeg 4x12 celestion cab. whenever I used 4 ohm mono only half of my speakers would work right ones worked when pluged into the righ side and left when pluged into the left jack . so I was told to rewire it . so I take of the back and now I think ive figured out the problem. I have 2 8 ohm speakers and 2 16 ohm speakers . is there any way to wire them in the same parallel so they all work at the same time or do they all have to be the same independence ???? thanks a lot , diagrams are appreciated.

edit : I also tried 8 ohm and 16 ohm and no sound is produced when I switch both my cab and head to these independences
Last edited by lambofgod127 at Jul 30, 2014,
I'm not a wizard when it comes to stuff like this, but I'm not sure that it is possible. You would want to wire the two 8 ohms in parallel, wire the two 16 ohms in series, then wire the two sides in parallel - and if my math is correct then that would equal a 16 ohm load.

But I'm not 100% sure if that wiring configuration is possible.
With the speaker impedances you listed, it is not possible to get exactly 16 ohms using all four speakers.
But you can get 12 ohms pretty easily.
The 4 ohm mono is using two 8 ohms speakers in parallel. Leave those that way.
Wire the two 16ohm speakers in parallel, making sure the "polarity" of each speaker is connected the same.
Then take wire the paralleled 8 ohms speakers in series with the paralleled 16 ohm speakers.
That works out to 12 ohms = 4 ohms + 8 ohms.
The output from both pairs may not be the same.
Quote by dkcol
With the speaker impedances you listed, it is not possible to get exactly 16 ohms using all four speakers.
But you can get 12 ohms pretty easily.
The 4 ohm mono is using two 8 ohms speakers in parallel. Leave those that way.
Wire the two 16ohm speakers in parallel, making sure the "polarity" of each speaker is connected the same.
Then take wire the paralleled 8 ohms speakers in series with the paralleled 16 ohm speakers.
That works out to 12 ohms = 4 ohms + 8 ohms.
The output from both pairs may not be the same.

is there a diagram for that ??? I have black and red wires , blue and yellow. im clueless almost at this stuff. also if the cab would be running at 12 ohms should I put my head at 4 or 8 ohms and yes its a tube head

edit: forgot to mention one of each speaker works meaning one 8 ohm and 16 ohm speaker run at the same time
Last edited by lambofgod127 at Jul 30, 2014,
Without the exact Ampeg model number, I don't know what color wires are for each pair of speakers.
Is the right jack might labelled 4 ohms and the left jack labelled 8 ohms?
If so, then the right pair are the 8 ohm speakers wired in parallel.
And the left pair are the 16 ohm speakers also wired in parallel.

Without seeing the actual cabinet, you could try this:
YOU MIGHT NEED AN OHM METER (DMM) to confirm the wiring.
1) I'm guessing the black wire goes to the shell contact on one of the jacks on the real panel. The shell is the outer, threaded part of the jack. If so, unsolder the black wire from the jack.
2) Unsolder BOTH the blue and yellow wires.
3) Solder the black wire to the blue wire. Don't tape it yet until finished testing.
4) Solder the yellow wire to the shell of the jack - where the black wire used to be soldered.
5) Plug one end of the cable that will go to your amplifier head into the jack that has the red & yellow wires.
6) Plug the other end of the cable into the 8 ohm jack on the amplifier head.
Try it, and if the sound is not very loud, you may have to swap the blue and yellow wires.
If it all works, put some electrical tape over the two wires that are soldered together.
Quote by lambofgod127
I have 2 8 ohm speakers and 2 16 ohm speakers . is there any way to wire them in the same parallel so they all work at the same time

wiring them all in parallel would give you about 2 ohm output:

1/8 + 1/8 + 1/16 + 1/16 = 3/8 = 1/Rtot => Rtot = 8/3 ~ 2.6 ohms

so if you wire them all in parallel they will all work at the same time, but 2 ohms will probably be a bit too low for you to use. here is a diagram for a parallel wiring.

Quote by lambofgod127
do they all have to be the same independence ???? thanks a lot , diagrams are appreciated.

it helps if they are all the same impedance, else the speakers that are lower impedance will get more of the current draw and sound louder than the speakers with a higher impedance.

i'd recommend getting speakers of all the same impedance.
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Wire the two 8 ohm speakers in series for 16 ohms. Wire that in parallel with the two 16 ohm speakers and the resultant will be 5.3 ohm. Then use the 4 ohm output on the amp.
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