Unless your 810 does not have speakon connectors then you need a speakon to 1/4 adapter or a speakon to 1/4 cable.
Ged ready to blow that 810! Ampeg lies about their power handling speaks. I can crank a 2001RB into a MEsa 810. Try going past 12 on the volume and those Ampeg speakers are gonna bark at you...
technically, they're not lying. they're stretching the truth. new math, I guess. of course, 2001RBs are for stadium gigs... so are mesa 8x10s. I've never needed anything bigger than a 4x10