Just sent my unit back. Just the unit without batteries and accessories. They're sending me a new one at the same time, I just had to send them a pic of my receipt of shipment.
I had a lot of hissing, very noticeable hissing, with my JH163A FP. What's more strange is, there was more hiss in low gain than mid or high gain, though the gain was working correctly. Many people suggested I got a defective unit so I contacted iBasso and got a fast response with instructions on what to do. Good thing they're sending me a brand new unit at the same time.