If you look at internal pictures, you can generally tell if something does not have a linear power supply because you will not see a really large transformer and the power supply board will have really small capacitors. Look at the Bryston BDP-3:
http://www.audiocircle.com/image.php?id=158255
You can see the larger round toroidal transformer on the left and 2 large capacitors on the power supply board with voltage regulators bolted to the bottom of the case.
In comparison, look at the oppo 203:
https://www.oppodigital.com/blu-ray-udp-203/images/UDP-203-internal-hr.jpg
Tiny yellow transformer in the middle is a sure indicator of switching power supply.
Oppo with linear power supply upgrade:
http://cfile5.uf.tistory.com/image/21207B4E586D8EFE34FFE5
You can see the huge size of the transformer in comparison.