Tube rectifier blew during a gig at a dive bar in St. Louis last month

I was running my homebuilt 5E3 Deluxe for a 3 hour set and about halfway through the second song the rectifier tube started arcing blue inside. I swapped in a 5Y3 I had in my gig bag and it got me through the rest of the night but now I'm worried about voltage spikes hitting the filter caps. Anyone else push a borderline rectifier or do you just shut down and miss the set?

2 comments

2 Comments

margaret_nelson10d ago

Arcing blue inside" yeah that's the classic sign a rectifier is about to give up. You did the right thing swapping to the 5Y3 on the fly. But those voltage spikes are real. I'd check your filter caps rating now. If they're 450v or less you might be pushing it. I blew a set of 400v caps on a similar 5E3 build after a rectifier went bad, and that was a mess to fix mid tour. Next time carry a spare 5AR4 or a solid state rectifier plug. Those are cheap and can save your set.

hugo508d ago

Gotta disagree a little with you on the spare 5AR4 or solid state rectifier plug idea @margaret_nelson. For a guy gigging out every weekend, carrying a spare tube just for the rectifier feels like overkill when a $5 copper cap fused plug does the same job and never dies. And yeah, those voltage spikes after a tube fails are gnarly. I've seen guys lose output transformers on top of caps because they didn't have a backup plan. But for a bedroom build like the 5E3, a 50 cent 6A10 diode in a plug is way easier than hunting down a matched spare tube. Just don't forget the heater load changes if you're going solid state.