I typically use a Rockerverb MKIII and its clear as day. 1 16 ohm cab...16 ohm jack. 2x16 ohm cabs 8ohm jack for each cab. I just bought a 75 OR80 today...not as clear. 2 jacks. Easy enough. Then theres the switch on the head...do I leave it at 16 ohms or do I kick the switch to 8ohms under the impression that it sets both outputs to 8 ohm like the dual outs on my rockerverb?