I just got a new Udac-2 HP and when i plugged it in, i was like OMG, there was clear difference b/w my onboard and the udac, but then after left it playing for 3-4 hours when i came back, i can't make out the diff b/w the 2!! is this some sort of bad burn in? I also plugged in speakers into it...

isnt anyone bothered by the decoding limitation of the fiio e7 to only 48kHz / 16bits sound?? i've heard other dac/amps and 24bit upscaled sound definitely does sound better..