I think the K5 Pro is a flawed product and shouldn't be bought.

You kinda say it yourself in the review: in neutral setting the audio sounds flat and lifeless. Reason for that is, when the treble/bass knob is neutral position it doesnt have a flat frequency response, the bass is still 3-4dB too little and the treble also falls of like 1-2dB.

So its not a DAC with optional EQ, its a DAC thats always EQ'd. You either have too little or too much bass. Is impossible to make your headphone sound like its supposed to sound, which for me personally isnt acceptable for that price, I would rather listen to an apple dongle than to this DAC.