Hi all, first thread here.
I have an old Sears 2x12 speaker cabinet built in the seventies. The ones from the sixties used Jensen 4 ohm speakers from what my research tells me but these speakers are unbranded and have basically no markings on them. I plan on eventually replacing them but can't afford that at the moment.

I have a valveking 212 combo and would like to try the cabinet out but don't want to blow anything up. The speakers are wired in series so the minimum rating could be 8 ohm right? I can adjust the ohm rating for the extension cab with my amp. If I set it to 8 ohm and the rating of the cabinet is 16 am I going to cause problems? Is there any way to figure this out without an Ohmmeter?

Thanks for any help
IF you have two 4-ohm speakers wired in series, you have an 8 ohm load.

If you have an 8 ohm output and the cabinet actually turns out to be 16 ohms, you're good. You can generally work with MORE load without damage. It's when you have LESS load that you can get into trouble (4 ohms, 2 ohms).
Thanks so much for the quick reply and awesome advice. I set my amp to 4ohm just to be safe and plugged it in and....... SOUNDS AWESOME!!!

It's a closed back cab so it really tightened the bass response (which was my least favorite thing about this amp). Those thrashy rhythm riffs now sound tight and mean as opposed to flubby and fizzy. I really don't know if I want to change the speakers now other than the fact that they seem a little quieter than the speakers in the amp.