Please help...

[seanzilla]

Hello, I just turned on my dual rectifier that I got last week and I was wondering why it just didn't have that oomph any more and I lost a lot of tone and volume was low. I turned it around and one of the big 5U4G tubes in it is not glowing. So I called GC and they said that if it wasn't working the amp wouldn't work at all. Is this true? or did I do something wrong? Please help.

Guitar center said bring it in and we will throw in a new one.

 

[NoGlassNoClass]

Usually a bad rectifier tube will blow the fuse...I suppose it's possible. Try removing BOTH the 5U4's, and switch the rectifier select to "Silicon Diode" and see what that does. If you get full power back, replace the rectifier tubes and you should be good to go.

 

[seanzilla]

Should both of the 5U4's be glowing? only 1 is.

 

[NoGlassNoClass]

They dont glow the same way as the power tubes...but you should be able to see a faint orange glow from the heater filiament.

 

[Platypus]

If a rectifier tube blew you would instantly blow a fuse and your amp would turn off. Even when your rectifier is in diode mode, the rectifier tubes are in the circuit technically, so it can cause issues. I had this happen to me on my dual.. the tone sounded fine but if I put out a lot of power from my guitar it would make this horrible sputter/dying fade sound as the note died off.

Eventually I blew a fuse. I troubleshot it and saw the tube make a jacob's ladder with my own eyes and that was the issue, even though I was on diode mode to test it.

I'd suggest looking at a different tube causing the issue.

Also, is the tube glowing at all? look close and see if it's the slightest bit on.. if it's not then that's very bizarre because the amp probably wouldn't power on, at least in my experience.

 

[seanzilla]

There was no glow whatsoever. At all.

Brought it to GC and it didn't blow a fuse but the tube was bad and he replaced both of them. now it works fine.

The new mesa 5U4G's are different on the insides. They have only 2 glowing deals on the top, the old ones had 8 glowing deals.

My amp sounds different though, not as bubbley and round sounding. This sucks, I had the best tone ever on there. Hmm, what to do.

whats will the sound be like if I throw some EL's in there?

also do I have to break in the tubes at all or do anything special that I have brand new rectifier tubes? I know dumb.

 

[jbird]

So, I'm assuming this is a three channel model which had the 5U4GB's, no? And now you've been given a set of 5U4G's? Actually, some of us prefer the latter for they're slightly tighter feel! Some complain the stock 5U4GB's are too flabby/muddy! With Rectifier tubes, there would be yet another option, the GZ34's, which are a little stiffer/tighter than the 5U4G's, also quite popular around these parts! So you see a gradual increase in feel (tightness, less mudd/flub) as you increase from 5U4GB's - 5U4G's - GZ34's - then your Diodes! Hope this helps!

 

[jbird]

Ooh! Also, you want more bubble on your clean channel? You might like the EL34's in the power section! And alas, you really don't need to break in those tubes! Roll it like ya stole it! :twisted:

 

[Platypus]

So, I'm assuming this is a three channel model which had the 5U4GB's, no? And now you've been given a set of 5U4G's? Actually, some of us prefer the latter for they're slightly tighter feel! Some complain the stock 5U4GB's are too flabby/muddy! With Rectifier tubes, there would be yet another option, the GZ34's, which are a little stiffer/tighter than the 5U4G's, also quite popular around these parts! So you see a gradual increase in feel (tightness, less mudd/flub) as you increase from 5U4GB's - 5U4G's - GZ34's - then your Diodes! Hope this helps!

+1

Also, there's nothing you have to do to break it in

 

[seanzilla]

Hey thanks guys, I really appreciate the help. On to my next post!

jbird - "roll it like ya stole it" never heard that, I had a good laugh.