Can i replace my GZ34 with a 5u4?

[loopjunkie]

So I got this older beat up UG30 and it had the worst mismatched tubes in it; It has a unmarked rectifier tube i have to assume is a GZ34 because that's what the amp is supposed to take but i have a real nice NOS JAN RCA 5U4GB that would love to replace that unmarked probally toasted (the other tubes where) tube? Will this hurt anything and are there any downsides to doing this?

[EL34]

Going from memory, I believe the 5U4 has higher heater current, so you'll want to be sure your power transformer is up to the task....probably OK in the UG30, which I'll bet is over-spec'd. A 5U4 should add some sag, a softer attack to the notes.

[Blue Strat]

What's a UG30? Underground 30?

Probably ok, but check with Tony Bruno to be sure. At best, the tone will be different as per what EL34 said, at worst, you'll cook your power transformer (unlikely, but consider this fair warning).

BTW, if the amp works at all with the rectifier in there, the rectifier is probably fine.

[loopjunkie]

OK guys, so i asked the man himself and the answer is no. Just in case anyone else was wondering.

[Bradders]

there's a great cheat sheet on the KCANOS tubes stie that talks about rectifier tubes and what can and cannot be swapped. I've used it a bunch of times..
http://www.kcanostubes.com/content/newsletter_details.asp?ArticleID=3

Great site - great tubes - great guys........

Beradz.

[farlowhigh]

fwiw, the Cowtipper used to have a 5U4 and now has a GZ34 and I was also told (by Ken Volpe) that you should use what is called for...mine is a Pro II CT22 and it uses the GZ34...

[emjee]

Thanks for the url Bradders! I wa sgoing to change the 5y3 in my Victoria Champ to a GZ34 or a 5V4. But after reading the page you referred to, they said this is ok but a bias check must be done (which I dont have the tools or the knowledge to do) after changing the tube. True? Thanks again.

MG

[loopjunkie]

there's a great cheat sheet on the KCANOS tubes stie that talks about rectifier tubes and what can and cannot be swapped. I've used it a bunch of times..
http://www.kcanostubes.com/content/newsletter_details.asp?ArticleID=3

Great site - great tubes - great guys........

Beradz.
Yeah i just ordered a set of GE's from them KCA;that guide was what got me thinking I could swap them LOL:jo. But the Ken guy is the one who said i couldnt so I won't. I ordered a NOS GE GZ34 (and the matching EL84's) from Big Mike. He is a really nice guy and real helpfull!:dude