Do I need a special cable, or will a guitar cable do? My Marshall is still in the shop, but I was thinking of running my blues Jr through the 4x12, just to see how it sounds.
The cab is wired for 4ohm or 16ohm mono, and for 8ohm stereo.
You probably could use a guitar cable, but it's best to always use speaker cable. A guitar cable designed for a different resistance and capacitance than a speaker cable. It might not do anything bad, but it could be risky.