I've been looking at the possibility of replacing the crystal oscillators in my DAC. I've read everything I can find here and at diyaudio about the Audiocom Superclock, Ultraclock, et al. What I'm not quite understanding is the distinction of these expensive units. For example, the...

I've been pondering the feasibility of running a pair of earphones directly from the current output of a dac. If you start with something like the Etymotic ER4 line of earphones where you can easily adjust the impedance of the phones and actually have something that requires very little...