I believe it is made by Inkel which makes Pioneer, Sherwood and many others. Not sure about Onkyo being built there but Onkyo doesn't build their own either. There are only 2 maybe 3 plants in China that pretty much make almost all major brand AVRs today. Yamaha is the exception they have their own plant in Malaysia but even Yamaha outsources its basic model AVR to be competitive.

I do know the DMS-AV was developed by an ex B&K engineers. It does bias its amplifier stage high so it runs hot even at idle which the Onkyos also do. If they are built in the same plant it is a good chance the same Chinese engineers were involved in the process of design with both brands.