Shenzhenaudio actually sent me a video on how to disassemble the PA5 during my customer-service disaster with them:
Their claim was that the noise was caused by a "loose connection port", and they wanted me to disassemble the amp and see.
A few things:
No way this was gonna fix the issue.
No way a random customer should be messing around with defective merchandise like this.
No way this can be called customer service.
Even if you are a qualified electronics technician, this is the wrong approach for warranty service. But, since warranty service isn't part of this product's bill of materials, at least you have the video!