"1\/4" Phone plug" = TSR. = In the case of LSR305 it accepts both balanced and unbalanced connections.\nYou'd just a cable like this one:\nhttps:\/\/www.amazon.com\/Tisino-Stereo-Y-Splitter-Cable-Breakout\/dp\/B07K58VX13\n\nThanks. I only looked at the photo of the rear panel, I didn't read the manual, and the label says "balanced". What does TSR stand for? I don't ever remember seeing that abbreviation for a 1\/4" phone plug.