Nice review shigzeo.  You should look into the Headamp Pico power if you want something with plenty of power, flexibility and a silent noise floor.

I have yet to hear the Pico Power, but I've enjoyed a number of Picos at meets. They are impressive. As a series, Rx has only the background noise floor issue. MKIII-B+ is the most flexible portable amp I've ever used. 

What does the "+" stand for? Battery life?

It may very well stand for that- or the plus mark may stand in the stead of a letter. I reckon it stands for some sort of iteration.

So why can't they just improve the noise floor . The Moment you say portable IEM,S come into the picture . Are we supposed to build an attenuation circuit to greatly lower the noise floor as I did ?

I own the B. It's a great sounding amp, but the hassle is just not cool. And the iBasso amp is quiet as I have both. It makes me wonder about there lake of commitment to improve there product .

Al

ALO claims the plus is just for an overall better amp. Battery life and SQ.