4x12 Problem

[Headof75]

Hey guys.
I've just bought a new old Mesa 4x12. Heard it demoed before sale and it sounds great, but I'm struggling with something. Opened the back and it has 4 16 ohm speakers wired together in two parallel pairs. The jacks on the back offer two sockets at 4 ohms for stereo or one at 8 ohms for mono, but surely with 16 ohm speakers I should be setting the amp to 16 ohm for mono and 8 ohm for stereo? Hope you get what I'm saying.

 

[Metaltastic]

Hmm, yeah, your right, it is 16 ohms in mono and 8 in stereo with 16 ohms speakers in series/parallel. Strange it would be that way, usually Mesa cabs have 8 ohm speakers so the overall impedance is in fact 8 ohms; I guess the previous owner replaced 'em for some reason!

 

[Metaltastic]

Just to confirm, though, you're saying it's wired like the bottom diagram on this page, right?

 

[Headof75]

That's what I figured but thr guy I bought it from doesn't know anything and having also sold his TSL says he can't remember what impedance setting he used to use.

 

[Headof75]

I'll try to clarify.
I'd seen this link from a post you put on another thread, by the way and thanks for answering.
The layout is basically two lots of the top diagram, 2 speakers in parallel. Top left + and - go to bottom left + and - and then to the input jack for the one side stereo, labelled 4 ohm, which I figure should be 8.
Same on the right. Then there are a set of four thick 'jumper' wires that connect each of the terminals to a corresponding place on a stereo jack, oddly enough, for the mono input.

 

[Metaltastic]

Well as long as it's 4 16-ohm speakers wired in that fashion, then 16 mono/8 stereo is the way to go! However, I can't imagine it'd make a difference, but to be safe, I'd pick up a Switchcraft Mono jack to replace that stereo one...