Well, it seems the iPhone 7 doesn't play well with the AF USB card even with a genuine Apple adapter! So, I then bought the AF Bluetooth module for the amp. Worked for a while and then when I started to play a song the left rear speaker would pop. Contacted Crutchfield and I was sent a new BT module. Same thing. And then the BT module stopped broadcasting its presence. Crutchfield sent me a new amp. Work for a while and the issues returned. I re-installed the AF USB module and bought a Fiio M3 Pro digital music player (
www.fiio.com/m3_pro). I had to run a 15' long cable with USB-C at console end and USB-B mini at the amp end. Finally, it all works!!!
Dark Side of the Moon as .wav files is unbelievable!