Can too much B+ filtering kill a rectifier?

[zhyla]

I recently bumped up the first filter node on my 5B6 Bassman from 33 uF to 66 uF. Once I did that I noticed when I was done playing and put the amp in standby there would be funny high pitched kind of sucking sound. Hard to describe. It wouldn't last for long (1/2 a second). Ok, really hard to describe but it kind of reminded me of turning off an old CRT monitor or TV.

Anyways, my 5U4 rectifier just died. At least I think that's the problem... 400 VAC going into it, 90 V coming out. I can hear something rattling around in it, I'm assuming it's just blown.

Hmmm, but then I just stuck it back in and it turned on ok. But I'm guessing it's still on its way out. I didn't think 66 uF was too much (I think one of the more experienced guys here suggested 80 uF when I was hunting down hum problems).

[cminor9]

Here is what I have been told: tube rectos don't like to see more than about a 40mfd cap in front of them. This holds true for the first cap, but after that a 66 could be OK.

I think that 66 killed your recto.

Or was that

Recto? Dang near killed em!

[zhyla]

Yep, dang near killed him. I didn't ever think to check the spec sheet for that kind of thing, sure enough 40 uF is the max for 5U4's. Thanks.

I'm kind of amazed at rectifiers. This one is 50 years old and if it weren't for my incompetence would probably still be going strong.