Hi GreenLeo,
Thanks for reminding me. I forgot to mention:
The Isabellina HPA is going to be best suited for "non-IEM" headphones. Those IEMs are just too sensitive and their sensitivity is in the noise floor of the headphone amp (and dac), so I don't think they will be the best match.
Non-IEM headphones like various Senns, AKGs, Grados, Denons, Ultrasones, Sony (R10s especially!), Audio Technicas, etc. are the ones to pair with the Isabellina HPA.
Sorry I cannot accommodate the high-sensitivity IEM crowd with this one

-Vinnie
PS: I'll be away this weekend (leaving shortly) and will have limited internet access - but I'll try to respond to questions as soon as I can.