OK, I get it that you just connect the speakers to the headphone jack. BUT, I have 2 older Harmon Kardon Sound Sticks with RCA plugs. They originally plugged into a Harmon Kardon woofer, and then the woofer plugged into a USB port on the Mac. But the woofer is dead. So, my question is: can I find an adapter to plug these Sound Sticks into and then plug into the headphone jack on the computer? And, just as important, will the headphone jack power the speakers?