The real potential of DAB+ lies in its digital audio data. Music is transmitted without loss of quality, digitally.
To fully benefit from this potential, the digital signal also has to be transmitted between the several components of an audio device until it reaches the human ear.
The Si468x chip that we use in our DABBoard has these features. And the Raspberry Pi as well. What is left to enjoy music in digital quality is to enable the I2S bus within the Raspberry Pi.
With the newest version of our DABBoard instructions we have added a manual about just that. Download the instructions to learn how to fully profit from the digital sound.
Is there a solution using dab hat and hifiberry amp2 and streaming data directly from raspi ?
You can check this page about I2S:
https://ugreen.eu/ugreen-dabboard-i2s/
What will not work is: you can’t stream data from the DABBoard to the Raspberry Pi through I2S and at the same time stream data from the Pi to the Amp2 with I2S. There is only one I2S bus (although it has a DOUT and DIN) and there can be only one device streaming data. There can be several which read this data though. So you can stream from the DABBoard and read it with the Pi and with the Amp2.