I am using this circuit to build an Arduino controlled gain-clone amplifier.
I have received the board and it works great ! The circuit design was copied from the TDA7439 datasheet.
The TDA7439 Arduino library can be found here : https://github.com/ahuxtable/TDA7439
See photo of the board and TDA7439 at the bottom.
The TDA7439Three-band digitally-controlled audio processor
Input multiplexer– four stereo inputs–
selectable input gain for optimal adaptation to different sources
Single stereo output
Treble, mid-range and bass control in 2-dB steps
Volume control in 1-dB steps
All functions are programmable via i2c.