Quick speaker ohmage question

Bidley

I'm using a 1x12 extension cab with my 1x12 combo. Both have 8ohm speakers. Is the impedance 4ohm?

MtB

Here's the answer - depends if they're wired in series or parallel:

https://www.eminence.com/support/wiring-diagrams/

ICBM

Almost all amps with two speaker jacks have them in parallel. If it's one of the rare ones with them in series it will almost certainly say so, since it would otherwise be assumed that they were parallel.

Short answer: yes, 4 ohms.

DJH83004

You don't state the make / model you have, some manufacturers switch the output transformer tap to 4 ohms, when the extension speaker jack is plugged into the extension socket, whereas others tolerate the impedance mismatch, as IC says almost always in parallel

Bidley

@DJH83004 @ICBM The amp is a Carvin XV112. Two speaker jacks, switchable ohmage. Cab used to be a Valvestate combo of some sort (has a Marshall-branded Gold Back in it) wired in parallel.

DJH83004

So, the internal speaker is 8ohms, the extension cab should have 2x16 ohm speakers in parallel e.g. 8 ohms, therefore plug the extension cab in, and slide the impedance selector to 4 ohms, all good