I understand that there are two output jacks, first one powers the amp speakers and the second one could power an additional 4 ohm cab and that there must be a jack inserted in output #1 for the second to function. I want to unplug the jack powering the 3 speakers in the combo and just hear a cab I picked up. Easy enough, but the cab is a 4 ohm load and I understand that the load from the 3 internal speakers create a 2.6 omh load. I think as a general rule, a 4 ohm output can power 4 or 8 ohms, going up one notch but not down to 2 ohm. So is it ok for a 2.6 output to power a 4 ohm load ( I believe yes ... want to double check ) and how is the 2.6 actually calculated from 3 speakers ? I understand that in series is additive and parallel is aXa/a+a ... and sort of understant that 4 speakers are a combination of series wired in parallel ... but how are my 3 blue frame speakers wired/calculate to create a 2.6 load ? Thanks.