Bought these used, in excellent shape, to use mainly for listening to FLAC files on my MacBook Pro using MPlayer X. Also ordering a Pono Player which I plan on running in balanced mode with these puppies. I noticed that Surf Cables makes balanced headphone lines for them, so I searched them out. Remarkably, I found a pair for 35 Canadian dollars. I have noticed after the first day that they seem to naturally carry a little more bass than my beloved HD 380s. Early indications are leading me to believe that the 545's soundstage is more spacious. I've already read favourable comparisons of the 545s to the HD 580s right here on Head-Fi. Super comfy. Apparently there is a intermittency issue after some age with the two pin connectors and their sockets. I haven't experienced that yet and hope not to. All I can say is that listening to Rush's 'A Farewell to Kings' at 24bit/96KHZ is a heavenly experience with the HD 545s!