Excellent review, informative and well written. The 'problem' I have with this amp (and the reason that I sold my 627) is the derisory 4hr run time, which is solely inadequate for most users purposes. Having said that, the 627 sound was so beguiling that I purchased the 627x to replace it!

4-hour battery life? T_T

Yup, 4-hour battery life. Really not the best for a portable unit, but for my purposes it's completely fine.

HD424 ... Wish I still had mine !!!!!

Feel free to purchase mine

Wow, the dx50 looks pretty nice stacked on top of it. I've considered getting a portaphile but I wasn't sure if it was worth like 3x the price of a uha-6s, especially considering that Nick from leckterton is going to make a amp-only unit. 

I remember talking to you in the AAMAML thread once but I forgot what it was about :x.

Sound like a great little amp. I wonder how it compares to a FiiO E12DIY with OPA627s in it.
 
The DIY is a limited run amp, so hard to find, but you can probably get one if you look around. But you'd have to order the OPA627s and solder them onto the little adapter yourself. Still, it's a great platform for experimenting.
 
I'm not aware to too many portable amps that use the OPA627. The are relatively pricey compared to other chips.

The DX50 stacks perfectly on top of the MICRO if you count the potentiometer. This is great because it lessens the chance of a sudden tweak to the volume and subsequent ouch moment that ensures. I can't remember what either
 
Man I don't need another amp bro (maybe I do) and I don't know anyone with the FiiO E12DIY either