#1
my new amp has one input jack for 16 ohms, 2 inputs at 8 ohms, and 2 inputs for 4 ohm speakers/cabs.

the internal speaker is plugged into one of the 8 ohm inputs. If I plug in an extension cab rated at 8 ohms, do I plug into the other 8ohm input in the amplifier, or do I plug them both into the 4 ohm inputs?

any help is appreciated.
#2
I'm 98% sure you'd plug them both in the 4 ohm input. I'd email the amp company just to be sure though.
I don't give a shit if you listen to me or not
#4
sorry to revive a kind of old thread but I got some new info from my electrical engineer friend. to recap, my amp has two 8 ohm outputs, two 4 ohm outputs, and one 16 ohm.

the internal speaker is plugged into one of the 8 ohm outputs. I wanted to know if I use another 8 ohm cab if I plug into the other 8 ohm output, or I plug both into the 4 ohm outputs.

the amp outputs for 8 ohms are wired in parallel according to the schematic. so I would in fact plug an 8 ohm cab into the other 8 ohm output and NOT the 4 ohms.

this makes more sense to me to plug into the same output as your speaker/cab is rated. the amp "does the conversion" rather than me the guitar player.
Gear

Gibson Blueshawk
American Deluxe Telecaster
Washburn Pilsen Idol
Washburn Golden Harvest
Washburn Acoustic D-30

Koch Classictone 210
Pignose G40 V
#5
If they're in parallel then that wouldn't work. Two 8 ohm cabs in parallel is 4 ohms.
I don't give a shit if you listen to me or not
#6
Yeah, two 8 ohm cabs is 4 ohms, that's why you'd plug into the 4 ohm spot.
I don't give a shit if you listen to me or not
#7
yeah, you're right.
Gear

Gibson Blueshawk
American Deluxe Telecaster
Washburn Pilsen Idol
Washburn Golden Harvest
Washburn Acoustic D-30

Koch Classictone 210
Pignose G40 V