An Ohmage to incompetency

[Augo]

Gearheads, after 8 years of playing through guitar and bass stacks I still can't fucking wrap my brain around ohms and resistance. It has been a topic of conversation with my bandmates so many times that we have all just completely confused the shit out of each other and now none of us is sure about anything. Can anybody give me a good, articulate rundown on the ohm situation, and maybe a list of acceptable amp ohm/cab ohm combinations, and a list of ideal combinations too? I currently have a 300 watt SVT classic with a switch for either 4 or 2 ohms. Just got a 4x10 orange cab that is 8 ohms and want to add a 2x10. Sometimes I will want to run through JUST the 2x10. What the h should I get?

[Antero]

What are the ohms on the 4x10?  If it's like 4 speakers of 8 ohms each you could rewire it to be all parallel and 2 ohms, and then get a 2 ohm 2x10 cab.  You could run either separately at 2 or both in series for 4 ohms.

I'm not sure if that's a good idea or not though.  I mean, the math is right but I don't know if that matter for the signal.

[Augo]

Ohms on the 4x10 says 8.
Amp can switch between 2 and 4, currently the switch is on 4 ohms.
From what I understand, this is just fine but the speakers are capable of handling more than the amp is shoving through.
After reading a bunch of forums and focusing I think I've figured out that what I want is a 4 ohm 2x10 cab, because when I run that parallel with the 4x10 cab, the total resistance will be 2.67 [ (4*8)/(4+8)=2.67 ] and then I can flip the switch on my amp to 2 ohms and all will be good. If I forget to flip the switch to 2 ohms when running through both cabs, though, I could fry up my amp (4 ohm amp running into 2.67 ohm cab combination is not sexy).
But with a 4 ohm 2x10, when I'm running through just the 4 ohm 2x10, I can get full power by switching back to the 4 ohm output on the amp.

I think I got this but I've been saying that occasionally for years.

[El_Josharino]

Nice joke in the thread title, brother.