The AK320’s 3.5mm port is also a mini-Toslink (optical) out. How you ‘plug in’ determines the output.
1) A 3.5mm mini-Toslink plug < cable > Toslink plug delivers raw signals to an off-board DAC (no internal 2x AKM4490 processing + 200 Femto-seconds clocking).
To use the unit as a standalone player + DAC (with all the ‘benefits’ of on-board digital processing/filtering) delivering electrical signals to an amplifier/active speaker system, connect with:
2) a 3.5mm (unbalanced) headphone plug < cable > 2 RCA plugs cable for unbalanced output.
3) a 3.5mm (unbalanced) + 2.5mm (balanced) plugs < cable > 2 x Neutrik plugs cable for ‘optimal’ balanced output.
Check out shop.iriver.com = PEF14 and PEF21 cables. Other options are also available on the www.
Most hi-fi amps have RCA input ports. If you prefer balanced, choose an amp with the requisite ports.
Opinions differ on whether the ‘benefits’ of balanced connections are audible on a desktop/HP rig. Depends on who/what you wish to believe