In my opinion, the arrangement of the boards in the steel case makes it possible to install an isolator or recklocker board. Now I am curious if you have heard from customers who have done just that.
Can the sound be topped?
At the moment I’m getting the best out of the device by switching off WLAN and Bluetooth, using a Raspberry 3 model B and plugging in USB terminators (Terra-Berry DAC2 Review - #61 by judydudi). The power supply is from https://www.osaelectronics.com/product-category/power-supplies/