IdontknoThey're ready to run from any source with a line level output on either RCA stereo or 3.5mm/.125" stereo: PC, smart phone, DAC, personal music device, you name it.
BTW, they're a combo of the earlier M200 series with some of the later Swan H series drivers. Easily the best kept secret of the entire line...especially if you like the Diva series's style.