I cannot speak to the quality control issues but with the low impedance of the iPod touch 5 it pairs beautifully with the SE846.
IPod touch 5th gen is the best standalone DAP I have heard with the se846 till date. If anyone doubts the SQ of the SE846 because it doesnt sound good, I would encourage you to listen to it through the iPod Touch 5th gen (not those earlier gen)