Originally Posted by pngwn
Bill-P writes a little about the C421 and based on his thoughts, I wouldn't pair it with the AD900x. I have the BH and E12 and I'm loving the AD900X/E12 combination. While Audio-Technica's new bass range isn't as anemic as their old AIR series, the AD900x sounds mighty nice with the (sub) bass boost on the E12 engaged.
I just read his review and it seems the only thing that E12 won over c421 is bass. However, what I'm looking for is cleaner midrange and larger soundstage 'cause my E10 adds a little too much warmth to AD900x and the ss is even worse than plugging directly to my iPad.
His review also mention that O2 beats E12 in most tests, and according to several people, C5 sounds quite identical to O2, Guess I'll try the C5 then. It's not that I have huge budget but I don't want to spend on 100$ amp since the differences might be very negligible coming from E10.