My main house system has a CD player into a Pioneer receiver (optical line) and put through Vienna Acoustics Mozart floor speakers, but I don't use it that often. My computer room where I play electric guitar has an iMac going to an analog out into an old Sony receiver (no digital inputs) into nice M&K B-1600 bookshelf speakers, but they're at uneven levels and poorly spaced. I just ordered a pair of IsoAcoustic isolation stands to set up the speakers better, and I'm thinking about picking up a Denon PMA-50 DAC & amp, where I can take advantage of the iMac digital output using a 1/4" to Toslink optical connection. Anyone using an external DAC instead of a PC or Mac onboard? Much improvement? Most of my music is 224 or 360 Mbps, but most are ripped from my own CDs so I can re-rip to higher (inc lossless). Thoughts?