Dragonfly Black and Red

[jiaco12]

I purchased both the Dragonfly Black and the Dragonfly Red to compare the two with the intention of keeping the one that suites my needs the best.  I have tried both of them with combinations of the following:
- Tracks: 128kbps and 256kbps mp3 tracks, rock and acoustic. 
- Sources: HP desktop tower computer, iphone 5c.
- Output: PSB M4U1 headphones, Monster Inspiration headphones, Sennheiser CX 300 II Earbuds
 
For some reason, I simply do not hear any difference at all, other than maybe a slightly adjusted volume, I hear exactly what I hear when plugged directly into the source.  Based on the number of 5 start reviews in various places, I feel like I must be missing something.  Any thoughts before I return these?

 

[Dulalala]

Well there usually isn't a very clearly audible difference between different solid state amps. Your original source must have had no underlying issues with your headphones so when switching to a new DAC/Amp there will be no (clearly audible) improvement. I would just return them if I were you unless you have a need for them in the future (such as using them with harder to drive headphones).

 

[Beanlipe]

I have a FiiO E18. I do realize quite a difference when I compare them vs my Moto Droid Turbo 2, specially at higher volumes, the distortion levels on the FiiO are way smaller. But maybe that's because of the amp rather than the DAC.
 
See if you notice any improvement over the channel separation.