Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: oogabooga23 on February 17, 2023, 08:51:51 pm

Title: Bad Rectifier Tube?
Post by: oogabooga23 on February 17, 2023, 08:51:51 pm

How do I know if a rectifier tube is bad? Not too long ago, I had a JJ 5AR4 rectifier tube blowing fuses left and right, so I ordered another one (same brand). After a couple of weeks, everything was fine until I blew a screen resistor, and I assume it was from cranking my amp up. That was fixed, but now my fuse blew after 10 minutes of playing. I switched to one of those SS rectifiers that you can plug in, and everything seems alright now. Is it possible that I blew the rectifier tube when I blew the screen resistor?

Title: Re: Bad Rectifier Tube?
Post by: sluckey on February 17, 2023, 08:54:27 pm

Quote from: oogabooga23 on February 17, 2023, 08:51:51 pm

Is it possible

yes

Title: Re: Bad Rectifier Tube?
Post by: tubeswell on February 17, 2023, 11:16:04 pm

You want 1N4007 (minimum 1000V 1A) protection diodes in series with your PT high tension winding and your rectifier tube plate pins. This will stop high VAC from taking out your reservoir cap (and possibly shorting the PT B+/HT winding to ground- threatening the PT) if the rectifier tube shorts.