The tube sockets look hand-soldered, but the bottom of the board has some cold solder on the through-hole barrels. However, it's soldered good on the top side of the board, where it must have been wave-soldered. No problems with this amp, sounds amazing!
I’m hoping the pcb mounted power tube sockets hold up with the heat. The older dsl had chassis mounted power tubes sockets , not sure why they changed that in the R version.