FiiO K3
Bass Boost, gain switch, USB-DAC
Question about FiiO K3
Follow-up question: ... or can the unit also be operated with the new Fiio M11?
Why should you have to do this, the M11 surely has a similarly good DAC in it, if so, the sound quality would certainly not be significantly improved. I use the K3 via PC and you can hear the difference very well, because the integrated sound card in the PC is usually not very good.