I recently scored a bass half stack at a garage sale from another bassist. The head is a Peavey Mark VI series and the cab has a 15in Celestion speaker, I have no idea what the brand of the cab is as the covering is pretty messed up.

The head has two outputs: one 2 Ohm and one 4 Ohm
The speaker is some ancient Celestion model called an AM5-T2935

I don't know what the impedance of the speaker is so I don't know how I would run the head through it. Can anyone tell me how to make thing thing work?