Swap GZ34 with a 5Y3 rectifier in AC30TBX?

[buddyboysteve]

What will happen? I am wanting to get earlier break up and lower overall volume. Will it hurt my power tubes / plates or create a voltage problem?

[WaltC]

It *might* work, for a while... but ... if the amp was designed around the voltage and current handling capability of the 5AR4/GZ34 tube, then it's going to put what I'd expect to be an unsustainable demand on a 5y3 and you're then courting 5Y3 failure, potential tube shorts, instability and possible damage to other tubes and components in the amp.

I'd not do it.

[zzmoore]

I should look it up before I open my mouth, but doesn't the 5Y3 draw 3 amps.? Wouldn't it be the PT that would burn down....?

[davemccarthy707]

Don't do it. Not a acceptable replacement.

[WaltC]

"Wouldn't it be the PT that would burn down....?
__________________"

naw, 1.9a for the GZ34 and 2.0 for the 5Y3. Now your 5U4....<G>(3.0a)

[zzmoore]

Hey Walt -
Looks like I had my tubes mixed up.
Thanks

[buddyboysteve]

Thanks for the responses and info. Good thing I checked first. Read it on the web that someone else did it and was curious. Not gonna do it. As for accomplishing my goal then... would you suggest power scaling mod or a simple attenuator? The amp has already been modded with MM tranny, choke, and Sprague caps so another mod would not be a big deal. Thanks again for the info.

[EL34]

Try a 5R4....should drop much more voltage than the 5AR4, and it can handle the current demand.

[Prairie Dawg]

Originally Posted by EL34

Try a 5R4....should drop much more voltage than the 5AR4, and it can handle the current demand.

Just what I woulda done. Make sure you have the real estate if it's a head because some 5R4s are pretty large, like the doorknob Cetrons.

I have used a 5Y3 variant in my AC30 for a while, it was a 6106 Bendix missile tube. It worked OK but a 5R4 is far better. If you need one quick I have a dozen here somewhere.

[smolder]

Some rec's can be swapped... but not all... this is a pretty descent guide:

http://www.kcanostubes.com/content/n...sp?ArticleID=3

[zombiwoof]

If you want something in between the 5AR4 and the 5R4, try a 5V4. I use one in my vintage Princeton Reverb, to drop the voltage a bit so it sees voltages to approximate 60's wall voltage levels. Also, you can get regular size 5R4's, you don't have to use the monster "potato masher" ones.

Al

[Ronsonic]

Yeah, but the Cetron 5R4s just look too awesome to ignore.

[zombiwoof]

Originally Posted by Ronsonic

Yeah, but the Cetron 5R4s just look too awesome to ignore.

What if you could get other tubes (preamp, power) that looked like those things? You'd have one strange looking mother of an amp!

Al

[doublee]

What rectifier would you put in a VChamp? It doesnt matter much no? The GZ is hotter?

sorry to de-rail!

[zombiwoof]

Originally Posted by doublee

What rectifier would you put in a VChamp? It doesnt matter much no? The GZ is hotter?

sorry to de-rail!

Some people like to put a 5V4 in a Vibro Champ, to increase the headroom a bit.

Al