Just completed a 5C3 replica for a friend of mine. I fired it up last night and nothing, so I had a good look and found a stray strand of wire shorting the grid stopper to a filament pin. Snipped that and tried again. The amp worked and sounds quite good - from the two quick strums of a guitar I did before shutting down. The current limiter wasn't full on bright, but it was brighter than I'd expect, so I had a look around and tried again, this time measuring the B+, which was around 280V. The transformer is a Hammond 290BEX and with no load it's delivering 450V with only the rectifier tube installed. With either or both of the preamp tubes it's about 430 - so they don't seem to be the problem. But with either power tube (6V6) in either socket I'm back down under 300V. I've just spent a good hour and a half tracing, checking the circuit and I'm not finding an issue. The tubes were good, I robbed them from another amp, so. Any ideas?