Will IPhone / IPod play ALAC connected to REGA DAC. If I only use a usb cable? Or I do need to have a special dock?
Rega DAC has a usb port.
If the Rega DAC has a "Made for iPod" logo on it, you just hook up the sync cable. Maybe put it upright on the dock stand (the basic white one from Apple, or the knock-offs) then hook up the sync cable. If the Rega only has a USB-B port, don't look for the logo, it won't play (because if it works with Apple, then the sync cable will work, and there's no sync cable with a USB-B on the other end). If that's the case you're gonna need one of those docks that turn the iPod/iPhone into a digital transport, and the Rega needs to have an SPDIF input compatible with its outputs.