I could be wrong, but it looks to me like the left-hand power tube is not working. The heater is not lit up (orange glow.) If this is the case, the amp will function marginally. You'll get low output as the other tube is still working, but it won't sound good. The picture looks like damage, and if repaired, poorly so.

Billm's idea of using chassis mounted sockets is a good one. PCB mount power tube sockets are a bad idea, IMHO. Especially EL84 based amps. Most designs run them very hot, which can cause problems with cracking the traces on a PCB.