I'm looking for a cheap upgrade DAC for PC. I have a pair of m50s and always hear the fiio E5 recommended but people are saying they can make the m50 sound worse. What i want is superior sound quality and i rarely play stuff at loud volumes (only mid volume), so i guess all i need is a DAC. The reason i want superior sound quality is because people are saying motherboard DACs tend to be terrible and i can possibly squeeze some more juice out of the m50s. So i don't need anything highend, just some good dacs for a newbie trying to upgrade from the ipod world.
 
Any recommendations?

I researched it for a few days last week and I ended up going with this one
 
http://us.hifimediy.com/index.php?route=product/product&product_id=50
 
Among the few that are considered best bang for the buck and it doesnt have a long shipping time like some of the others.  Google it few good threads out there about it.
 

Just googled the E5 and it is an amp not a dac.  I just ordered a new amp too and went with this one which is $99 shipped
 
http://www.head-fi.org/t/644363/c-c-bh-portable-headphone-amp-80-hours-from-a-single-charge-buyer-review
 
Not sure which you are really looking for dac or amp. 
 

I thought E5's were amp/dacs. And i'm a newbie to all these stuff but i'm guessing because it is so cheap the amp made the sound quality worser for the m5? Just my theory on those people saying E5's lower the sound quality for m50s.

The e7 is a combo dac/amp.  The e5 isnt.