I'm not sure...it doesn't sound as if something is wrong, other than what I have mentioned. Everything seems to be working on it. But it's early days yet. At this moment it will have been only about 21 hours in burn-in. I still have hope it should come good within the 100 hour mark. I haven't used other headphones as of yet, but will try with my AKG K551 if the Shure doesn't work out. But it's a bit weird, because I feel the Shures actually are that good that they would have good synergy with almost anything. That's my experience so far...that they aren't that fussy. They play what they get thrown at them, neither enhancing or subtracting anything. I could also try my HRT Microstreamer as DAC to the C&C to se if it's the Hifimediy that's the problem. But either way...the C&C should be better than a FIIO E07K....right??
E07K sounds darker and less detailed for me than Hifimediy dac with BH, I tested the E07K together with Mad Dog and DT880 both can detect the difference quite easy. Much more engaging aswell on the BH than E07K, the E17 is better but still not as refined as the BH and Hifimediy dac. As for burn in there is not much to that can change inside a electronic device like this even on the measuring side.