All of this information is covered in the manual. Why cant people just read it. They make it real simple to understand.

Your amp probably has an issue that was missed when inspected. This is not uncommon with Accessories4less. I have had to send back a few items from them that didn’t work properly after I received them. Many people have no issues but I’ve had multiple. Customer service is spotty so hopefully they pay for the return shipping. I stopped shopping from them unless it’s speakers.

The DAC chip makes up maybe 10% of the equation. In the end it comes down to the chip implementation, analog output stage, and power supply. How well these are implemented and work together is what creates the differences people hear.