I am Not an owner of the HO200 or A90, so I can't help you much, but..when you said a "noise" is like hizzzzz like distortion ? or a different kind of sound? .I'm sorry for my poor English, but can someone please help me?
I had a hard time deciding between the "A90" and the "HO200", but in the end I bought the new HO200.
When I received the product, I turned the gain switch to MID and was very satisfied with the clear sound that came out of it.
However, when I switch the gain to HIGH, there is always an obtrusive noise coming through.
By the way, when it is on HIGH, the noise continues to flow even when no song is being output.
Is my unit the only one that is malfunctioning?
if your headphone is IEM and you put in high gain, that could happen,
which headphone are you using? how many ohms?