Cover plate for Chinese dual AK4490 DAC board

thingiverse

I'm designing a face plate for my Chinese dual AK4490 DAC, and I've got it almost right. My first attempt was a bit wobbly, but I've since thickened the design to 3mm. The plate can be securely attached to the cinch and optical ports using screws, and there's even an extrusion that fits snugly into the two mounting holes on the PCB. I didn't keep track of what type of screws I bought, but they're just basic ones from the hardware store. Measuring them out, I found that they have an overall length of 8.14mm, a shaft length of 5.5mm, and a head diameter of 5.44mm, with a shaft diameter of 2.86mm - so it's likely a M2x5.5. I had to fix one small bug in the design for rev1: I made the PCB screw hole mounts slightly too big, which meant I needed to add some extra spacing for the resistor at the coax input. However, I placed it on the wrong side and had to cut it away. To resolve this, I shortened the mounts from 12mm to 9mm. While making these changes, I also uploaded the source file in Autodesk Inventor 2018. My DAC is a double AK4490eq board, which I purchased from "HiFi College Store" on Aliexpress. If you're interested, it's available here: https://www.aliexpress.com/wholesale?SearchText=double+ak4490eq+board. One thing I discovered was that adding a low-pass filter to the voltage supply lines of my USB cables helped reduce noise significantly. It's not as effective as isolating the DAC from the PC ground, but it was a cost-effective solution that worked well. Even with silence playing at maximum amplification, there's only faint noise present (which would reach about 110dB to 111dB maximum SPL with my system).