I am currently pairing the Q701 and Audio GD NFB 15. I have recently purchased the AKG K712 pro, and was wondering whether it would be better to pair these with the Audio GD NFB 15 or Audio GB NFB 11? I don't currently own the NFB 11 and still waiting for the K712s to arrive, and was looking for some advice regarding which of these amps would be best, and whether the NFB 11 was worth buying? The Q701 with the NFB 15 – in comparison to the NFB 11 – is said to be a good combination, because the NFB 15 deals with the Q701 "shrillness" some claim to experience and dislike in the top end. Compared to the colder more analytical NFB 11, the warmness of the NFB 15 is said to balance out the somewhat dry, analytical Q701 sound; hence the NFB 15 is said to offer body to the Q701s, which also benefits their bass lightness. However, for the K712 pros, I was wondering if the NFB 11 might actually be the better of the two DAC/AMPS to pair it with? The K712s have a warmer and darker sound than the Q701s, therefore the more analytical NFB 11 (with no filtering its upper frequencies) presumably would be better for them? Since the K712s are known to have a more intimate sound stage than the Q701s, I also presume that the more analytical NFB 11 sound is going to help with sound separation?