What model tube amp is this?

[BluegrassDan]

Hello all,

I'm wondering what brand/model tube amp this might be. The National model 22 from the 1960s looks similar, but I wonder if it might be made by Danelectro, Coral, Valco, or someone else.

Any thoughts? Thanks in advance!
Professor Dan's Workbench - Danelectro Tube Amp - YouTube

 

[BluegrassDan]

After some research, it appears the schematic is that of a Supro S6616.