mr dave

What kind of amp?
Do you mean like having a 4ohm and an 8 ohm cabinet hooked up to the amp at the same time?
Or something like two different cabinets for two separate tones while using an A/B switcher box to bounce between both?

I'm no expert on stacks (I'm sure GB or RezZ will correct inaccuracies) but I don't think it's possible to run two different cabinets at the same time, flip flopping should be fine though. Just remember to make sure the amp is set to the lowest ohm rating on the cabinets, having the amp set to 4ohm with a 16ohm cab is OK, going the other way, not so much.

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