Hey ya'll, so recently I bought a 'matching' pair of the older traynor 6x10 cabs. I just recently noticed that on the two sides that face each other they have these two jacks. so i assume they a matching pair. https://pbs.twimg.com/media/BairNzyCMAARENU.jpg:large i haven't the slightest on how they work. so hopefully one of you can shed some light on 'em. thanks.