From what I've read, there's also a lot of desktop amps that have irregularities with IEM resistance/sensitivity to cause a lot of hiss as well. My only IEM is my workout BT earphones (probably a great format that eliminates any of those issues). I would think that if you're determined to use any source, it would be possible. The main issue is sensitivity to resistance. Would be a good DIY to research your amp output vs IEM specs (and then determine what resistor to use in a makeshift adapter).