A big trouble has occurred in D50, and shipment is currently delayed.
Large noise appears in ASIO (Native) playback of DSD with D50.
The way it's been described it sounds like a thermal problem with the DAC. Given the pics I've seen of the D50 I wondered whether that might be an issue given that there's apparently no thermal pad to conduct heat directly from the chip to the case and the tight case is restricting airflow. Seems like there was some miscommunication between the PCB guy and the machinist on the case design. If that's what it is it'll be an easy fix.
An easy way to test this is to remove the board from the case and play the same DSD file while a fan is blowing on the board.
The case was obviously designed with both thermal conduction and EMI reduction in mind but unless there's an appropriate conduction pad (and properly sized metal stack to the case) it won't work well and will actually make localized thermal problems much worse due to the lack of airflow in the case. It's also possible that even if the ES9038 has an exposed thermal pad on the bottom that Topping didn't connect it to an appropriate power plane, but even if they did it might not be enough given the small size of the board. I suspect they might be trying to use the mounting screws to conduct heat between the ground plane and the case but that's not a very reliable technique.
I know that the thermally conductive silicone pads come in a wide range of thickness but people will be better off using a thin one and filling the gap with a chunk of aluminum and using JB Weld or something to adhere that to the case (or just have a thin pad on both ends and use some other technique to keep it in place).
When the board is mounted in the case how much of a gap is there between the case and the top of the ES9038? Given the small size of the ES9038, if there's enough room the simplest fix would be putting a flat head machine screw or hex bolt in the case directly above the chip. That way you could easily adjust the gap and the pressure on the silicone pad. If there's not enough room as is then you could drill or mill out part of the case in that region since the case looked pretty thick there, and there's enough room between both chips for 2 screws.