Replacing Tubes

[engulfedinlies]

I got my 3 Channel Dual Rectifier about 2 months ago, and I got it used from a guy who said he had just replaced the tubes. I noticed that one of my power tubes (5U4GB) is not glowing like the rest of the tubes when I turn it on. I was going to just replace that tube by itself, because I'm figuring it must be blown. Should I replace all of the tubes just to be safe or just that one?

 

[Flashpoint]

First off, the 5U4 is not a power tube, it's one of your rectifier tubes.

Now, is the tube not glowing at all? Or is it more dim than the other?

It's not that expensive to go ahead and replace the rectifier tubes and re-tube the entire power section. To me, it would be worth it for peace of mind.

 

[engulfedinlies]

the tube is not glowing at all

 

[Living_justice]

replace the tube, i would, as goes for retubing, up to you realy,
i would starting buy the tubes good to have backups anyway, like buy the preamps one mouth and then the powertubes the other, i say preamps frist they like to go frist little bastards.

 

[Flashpoint]

Okay, here's a quick way to verify whether it's the tube or the socket:

swap the 5U4's around. If the tube STILL doesn't glow, you've got a faulty rectifier tube. If the tube in question begins to work, and the other one doesn't work... the fault is in your amp.

 

[stokes]

Could also be that you just cant see the filament glow,some tubes are harder to see than others.Just set the amp so that rectifier is supposed to be operating and if the amp works,the tube is good,if the tube is bad you wont get any power to the rest of the amp and it wont work at all.Basically rectifiers either work or they dont,a somewhat weak rectifier isnt going to exhibit very noticable symptoms till it dies.If that tube doesnt operate alone,i.e. it works with another rectifier,you will notice a loss of power if it isnt working at all.

 

[engulfedinlies]

i've been running the head in silicon diode mode. and the tube is completely dark. how would i know if my amp was running in 50 or 100 watts?

 

[stokes]

Put it in tube rectifier mode.If your amp still works the tube is okay.I dont have a schem for this amp,if it has two rectifier tubes,pull the one that is glowing and try playing it at low volume setting with just the suspect rectifier,if it plays your tube is okay.

 

[Kung-Fool]

Rectifier tubes don't glow very bright at all.