Hello to everybody.
 
I am before making a decision of buying portable amp that will fit best to my HD-600 headphone and Olympus LS-5 sound recorder which I also use for listening to the music (all wav files) and to music I like most of all - Renaissance and Baroque. I chosed four amps: iCAN Nano, SR-71A, ALO Rx MK3 B+ and The International+ but I have no possibility to listen all of them before the buy (only iCAN Nano), Actually I do not need DAC but if such amp gives better quality of music (iCAN Nano and The International) and better suits to HD-600 and classical music, I would chose it. What would be your recommendation?
 
Thanks in advance!

I only have the International+, and it's a very versatile device. I haven't heard the others, but on high, it can drive the AKG K712s (not the hardest headphones to drive, admittedly) to very loud volumes that I tend to avoid on medium gain. The other choices don't have a DAC option, which was the dealbreaker for me when I was picking out which amp to buy.

I just got the International+ and it sounds very good - a nice upgrade to my previous portable standard, iPod classic/CLAS/ALO mkII.  In comparison:  deeper bass and better sense of 'presence.'  It is also very silent and works well with my JH-5s.
 
I'm told the ALO MkIII has hiss when using certain IEMs but I really haven't had a chance to try it out.  I chose the International+ for it's compact size, DAC capabilities, and 'balanced' amp sound.  I did not purchase the MkIII as I read that it may be better for louder-type music (techno, etc.).  My musical tastes run the gamut but I prefer female jazz, chamber music, and pop vs. heavy metal and big symphonic recordings.
 
Hope this helps.
 
CJ

Thanks.
 
I am close decision to buy SR-71A, seems it makes sound I like.