I must admit, i do not have hard-to-drive headphones but this little amp add nothing!
and thas a good thing!
Ok it adds power... that gives greater stability thus cleaner sound but soundwise no added coloration is what i meant.
 
I really like RSA Stuff!

Good sound quality and good comfort. It is fairly lightweight but durable. The stock cable has some horrable mechanical transported contact noise (Some call it microphonics but microphonics is where mechanical vibration is transformed into electrical signal) so i replaced it with the HD650 stock cable. Yes i had to reverse the cups to make it fit.
I use it with a rockboxed iPod video and the RSA Hornet. Listening with crossfeed on i can listen to this combo for hours.
I listen mainly classical music. Opera, orchestral works, string quartets etc.
In my opinion, a closed can does not need to be perfect. i use a closed can to be isolated from outside noises but no passive closed headphone can isolate me for 100% so i will hear always hear some distracting noises
 
a great allrounder.
I do not really need a neutral sounding headphone since what is neutral nowadays? only my own ears listening to a live concert.
and my ears are not yours
 

I tried many ways to fit these headphone but i can not find a way to make it fit confortable. i cannot listen to this headphone for more than 30 min than my ears start hurting. i tried bending and repositioning but it does not work for me. My trusted HD25-1 II with the velvet earpads and shortened HD650 cable sits much more comfortable on my head and can listen to it for hours.
Yes, the DT1350 is sonnically a bit more neutral / ballanced but what good does it when ears are hurting?
So comfort and quality must go hand in hand in my opinion.
Soon i'll try the amperior