Run a cable from the headphone port on the Mac to one of the inputs on your preamp.
Computer to adcom amp/preamp
After the tot broke the CD player, the stereo system went into mothballs. Fast forward 15 years and he is recording music into a Mac mini using a tone port connected by usb. Hoping to use our old Adcoms and Bose acoustimass 5 speakers for playback but the only output from the computer is an aux cord for little headphones or the tone port's big headphone electric guitar-style jack (sorry I don't know the technical names). The adcom preamp GFA535L has left/right inputs. Do I just get some kind of connecter that splits the output signal? Will that sound ok? Any other suggestions?