DFplayer Mini plays in slow motion

Hi! I'm having problems with my DFPlayer mini. I had it working fine on a breadboard but since when soldered in place It seems it plays all the songs in slow motion kind of fashion where they go slower and sound is somewhat distorted. What in the world could be causing this?

I measure 5V on my DFplayer coming from that DFRobot 18650 holder. The mp3's are in 44100 Hz and Bitrate is 32kbps. 

 

 

Regards

- Björn