This surprised me a little bit
I haven't listened to AMP5 much because all my IEM's are using CB12 or CB13 balanced cables now. I do have a 2.5mm balanced to 3.5mm SE adaptor though.
The one time I listened to AMP5 was when I got the IT01 with the stock cable.
My immediate impression was of a significantly more warm and organic sound signature, delightfully musical and fun.
This was coming from the IT03 and Noble Katana, both with AMP3 though.
So a lot of that impression was doubtless due to the IT01.
But anyway, now you've intrigued me.
I'm going to use my adaptor and do a bit of back and forth with the AMP3 and AMP5, using the IT03 and CB13