I have a few other sets I'm happy with, just really liked the sound of the 400se's. They agreed to refund me. I will say, their customer service is as good as their quality control is bad.

Fair enough. I just can't find anything else with the same sound as these and I really love them.

For some reason I always forget about this as a possibility but I will ask them this time if I can just return for a refund.

Every single replacement that hifiman has sent me (and they've all been brand-new units) has either awful channel imbalance or one of the drivers rattling like crazy. Now my 7th pair just started rattling loudly in the left ear and I've only used it about 3 times. There is no hair or anything causing the rattle except the driver itself is clearly defective.