No matter what you use, it will not improve the overall sound of the device as it uses a cheap and crappy sound card. Any sort of amp including the Fiio E6 only brings EQ to the music, not to mention you actually lose sound quality because your using a jack to jack method unlike the iPod where they have special cables that connects directly into the DAC of the iPod because of the special provide cables which over-passes the direct headphone jack port. (Search up Fiio L9 Cable) Also when using the jack to jack cable that's provided with the Fiio E6 it lowers the loudness of the sound when connecting via phone to the amp.
Of course then there's the human ear, if you feel like it sounds great, good for you but in reality the sound is worse with EQ added to make you think it sounds great.
If your an audiophile you have to accept that the SGS2 isn't the best music device. Cowon for example or the SGP are good sounding music players. It's a waste of money to buy a Fiio E6 Amp unless your using an iPod to be honest cause it significantly improves the iPod devices.
That's my 2 cents, take it or leave it as you wish.
Last edited by Intercrew; 9th March 2012 at 12:25 AM.