The long lead between B5 and B6 will cause tremendous problems if those two terminals touch. The LED at A3 needs to have its lead wrapped up and around the tube socket terminal before soldering. I can't see the soldering at A4, but it looks possibly suspect. The wiring from the RCA jacks to the volume pot (which should be braided) is touching the green wires that heat the tubes, and this can lead to noise issues in the amp.
Doc found the reason all your DC voltages are 0V.
The UF4007 diodes are not installed as directed in the manual.
The bare tinned bus wire that leaves the safety earth lug by the IEC power entry module appears to be loose and not connected/soldered to where it's supposed to go.
The black wire going to power transformer terminal 15 needs to go under the 6 lug strip, not over it.
The white wire going to the headphone jack is improperly routed.
The wire leaving B2 and going up to terminal 2 should route under the terminal strip.
To make it easier to trim leads, the CHP-170 side cutters are inexpensive and widely available.
Although this seems like a crazy long list, I think all of this could be addressed in well under an hour.