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When does a 5V4G/GZ32 have to be replaced?

Hi all, this is my first post here, and I would appreciate some help! :)

I have a custom made pre+amp built on 4 triodes and a 5V4G rectifier. The triodes are relatively easy to keep an eye on (I am measuring the cathode current), but what about the rectifier? How do I test whether it is still in a good shape (preferably, without removing it from the socket)? Would measuring the actual filament voltage (that is directly fed from a secondary winding) tell me whether the tube is still alive?

Thanks!
meisterfloh
ths364
181 posts
 
In my experience they rarely need replacing unless they fail.I would keep a spare on hand though because when they go bad they usually just stop working with very little drama (although the other tubes are not going to light up either).
If it makes you feel better you can remove it from the socket whenever you change the output tubes and shake it next to your ear to make sure that none of the internals have worked loose. I had one rectifier tube that was sketchy and had a piece loose inside- sometimes the amp would work but after moving or transporting it it wouldn't work at all...until I moved it again.
hifihvn
943 posts
 
I would not check the voltage on the rectifier tube filament, if that is what your speaking of. The voltage there is several hundred volts, and *deadly*. Even if you could measure it, it wouldn't tell you the condition of the rectifier. The high voltage will be on all the pins. That tube changes the high voltage AC, to high voltage DC. Way to risky unless you no what your doing, and have a good high quality meter capable of handling the high voltage there. Plus you would need a schematic for, and understand it.
hifihvn
943 posts
 
Pardon the grammar, I just got worried about losing a new member.
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