I’ve had the blue sound, the Lumin, the Cambridge, the overall advice is that it’s hard to logically separate what these devices do. If it’s only to transport bits into a DAC, or to provide a processed signal, and does it attenuate volume? One of these three will give clues as to what may cause audible differences. My bet is in that pesky volume knob. I ended up with a crazy expensive preamp just because that volume knob seemed to make a huge difference. I’m thrilled with the Apple TV to control the music and deliver bits to the dac and then preamp has the volume knob. If a product can handle all three it’s great but all I’ve listed didn’t tick the box in my listening.
