Hey I just recently purchased the Beyerdynamic DT-990-Pro-250 headphones http:// and I know an amp is needed for them as well. I was wondering if anyone could help me on the differences between FiiO E10 http:// and FiiO E10K http:// since the E10K's price is alot more reasonable for my budget. Also, would the E10k be just fine for the headphones as well? Thanks