I still have to doublecheck all the cab impedance permutations whenever I have to match a cab to an amp. It’s not something that comes naturally to me at all, and that’s after over 50 years of gigging, etc.
We used to do the craziest things connecting amps and cabs, like daisy chaining two amps via their various input jacks, using guitar cables to connect amps to heads, and at some point I connected a Hammond organ output tapped at the speaker connection to the input on my Fender BF Bassman head, and nothing blew up (thankfully!). I actually got sound out of this contraption,
We used to do the craziest things connecting amps and cabs, like daisy chaining two amps via their various input jacks, using guitar cables to connect amps to heads, and at some point I connected a Hammond organ output tapped at the speaker connection to the input on my Fender BF Bassman head, and nothing blew up (thankfully!). I actually got sound out of this contraption,