Got the Amp+ to work on 5/5/2015 Fresh Raspbian.
A sample MP3 is playing with success with "mplayer" in the Speakers.
Now that i know the Pi and AMP+ are working together, i went back to my project ("Music on hold" audio player)
This project is coded in Python using Pygame as an Audio Module.
When i started the Python App (that was working properly with the Pi standard 3.5mm audio connector prior to the AMP+ Install)
The Python app react properly on screen, but faint static is heard in the Speakers.
When i Kill the Python App, the Static stops.
Here is the result of aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpihifiberry [snd_rpi_hifiberry_amp], device 0: HifiBerry AMP HiFi tas5713-hifi-0 
Subdevice #0: subdevice #0
The (simplified) python code is:
**Loop while playing**
I have a visual progress bar that follows the playback speed, but only faint static is heard in the speaker.
The Python App would not run until i deleted the /etc/asound.conf
It was complaining it was old or currupted (deleted it and rebooted)
Pi B+ & AMP+ Audio playing with mplayer, not with Python Pygame