- May 4, 2020
Thank you May, I was not honestly aware of this. Thank you for the clarification.Sorry, but this correction also needs another correction.
In the USB signal path the Sabre ESS9023 DAC is NOT involved. The USB input is the only one that does not pass through the ESS9023.
Thanks a lot for your answers, I just bought another one!www.audiosciencereview.com
"...The ES9023 DAC takes on digital-to-audio conversion for the Coax, Toslink and Bluetooth signals. But not the USB. Bummer. The internal DAC and "Headphone Amplifier" of the Realtek ALC4050 drive the NJW1194 volume controller directly. Even though the device supports I2S and could have been fed to the ES9023, it looks like we are left with whatever proprietary DAC exists inside the Realtek part, which probably isn't all that great. It's supposed to support 32-bit/384kHz but yet the DAC poops out at a 100 dBA SNR. Not a big deal, if you want better USB support, you can always get a USB-Toslink adapter and run that into the A30 to take advantage of the ESS DAC. But that's the only way if you're keen on USB audio."
All in all, also looking at performance of AUX in, best way to drive this amp seems to be the Toslink or Coax. I have no clue why the AUX in, according to Amirm findings on his tests, performs significantly worse (more than 10dB SINAD!) that the corresponding digital input.
My best, Ale.