[enchilada]

Hey guys,
 
I'm a long time lurker here but I've finally decided to join.
 
I've built a CMOY bass boost headphone amp from Fred's amps here in Australia. It sounds fine from my TV's headphone output but with my HTC One m8 it sounds weird and washy like phase cancellation.
 
I've looked into the TRRS pinout of the M8 and Google tells me it's:
1 - Left
2 - Right
3 - Ground
4 - Microphone
 
I've wired a TRS to TRRS adaptor wiring T to T, R to R1 and S to R2 but this hasn't helped at all. The phone sounds fine with TRS headphones plugged directly into it but as soon as I plug in the CMOY it's no good.
 
Any ideas?
 
Kris
 
EDIT: I did try a regular TRS cable first, which prompted me to try a TRRS cable but the issue persists with both.
 
EDIT2: Tried it with my iPod again and my wife's Galaxy Note III and it's the same issue.

 

[Armaegis]

Maybe on the adapter tie the sleeve to sleeve instead of R2?