Ok so i have a 100watt all valve head and two 4x12 cabs, one is 16 omhs and the other is 8omhs. The head can be set to either 4,8, or 16 ohms. Soo if i wanted to run the two cabs at the same time, would I:

A: Set the head to 16ohms, run the 16ohm cab first then run a lead out of it and into the 8ohm cab. (is this doable without causing damage)
B: Dont do it your gear will die?
I don't think that'll work. I don't know enough about this but I don't think mixing different cabs is a good idea.
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figure out if your speaker outs are wired in parallel or series. then figure out if you can plug into a mixed pair at the same time. then math out what the split would be with a 16 ohm and an 8 ohm.
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well, if you run them in series the resistance will be 24 ohms, it will work but not be optimal.
it shouldnt harm your gear.

i cbf finding what the resistance in parallel would be
You MIGHT end up with a 12ohm setup. You have to check both cabs manuals (haha) or open them up and work out if the extension is in series or parallel or it is switching when you attach the second cab. If, as is likely, each cab has 4 speakers of the same rating (16s and 8s,) you can wire all the 16s in parallel to give a 4ohm cab and all the 8s in series, (32) making sure your connection is a series one. Then you would have 32 plus 4 = 36 divided by two tp have 18ohm overall and work them from the 16ohm output. There are lots of combinations if you customise and a quick bit of research on the sums will let you calculate all the possibilities.
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