Type: DAC + AmplifierInput: USB / Optical / COAXHeadphone-out: 6.3mmLine & Pre-out: RCA (Switchable)Type: DAC + AmplifierInput: USB / AUX via RCAHeadphone-out: 6.3mmLine-out: RCAType: DAC + AmplifierInput: USB / Optical / AUX via 3.5mmHeadphone-out: 6.3mmDigital & Pre/Line-out: Optical / RCAType: Amplifier (DAC or Phono-Pre as optional upgrades)Input: 3pin XLR / RCAHeadphone-out: 4pin XLR / 6.3mmPre-out: 3pin XLR / RCA