Mesa 7i96 Output Wiring

That look correct as long as the valves have flyback diodes
(it looks like they do)

I believe they do. a led there at least 

---This has NOTHING to do with the subject, it is a public announcement to be careful on the internet!!!---

Those pictures are proof of how bad the internet has become, notice the L and N marks, that would imply mains voltage (110V or 220V) as L stands for a phase and N for neutral, yet this is for a low voltage DC equipment that clearly has marks + and - on the board.