5AR4/GZ34 versus GZ32, blown tube....

[CB Amp]

hello,

I received an european amp with a GZ32 rectifier tube. I did not have any of this tube, so tried to replace it with a GZ34 (5AR4). It was working with the GZ32 (I recaped the amp before). But the GZ34 blew quickly after the heating period, as the main fuse. No red plates, but a flash inside the tube, at its base near the pins connectors.

The GZ34 should handle more voltage than the GZ32 (450V vs 300V), it just draw less current. The amp has 2 6L6, 3 12AX7, 1 ECL86, 1 6AV6.
A GZ34 should handle this amount...

Did I make a mistake ? Was the tube faulty (brand new JJ) ? I wouldn't like to blow another GZ34...
Thank you.

[Structo]

Yes the GZ34 draws 1.9 amps and the GZ32 draws 2.3

In looking at the tube data I don't see anything that stands out that would be a problem with running the GZ34

Which tube arced?

Was it a power tube?

Maybe the power tube shorted out, taking the rectifier with it?

[Firestorm]

Check the socket wiring. And look for a short somewhere along the B+ rail. If I read you correctly, the fuse blew, too, right?

[CB Amp]

The fuse blew and the GZ34 arced. All the tubes were new.
The wiring of the socket is correct, and there is no burned mark on the socket.
I put the GZ32 back, changed the fuse, the amp works... faulty GZ34 ?...

[Firestorm]

Sounds like. It can happen with some of the new manufacture stuff.

[CB Amp]

yes...
I already had problems with JJ tubes : a 6l6 (vacuum, "white" glass) and a 7591 (heater). I think I will stop to buy them...

[davemccarthy707]

JJ 5AR4 = junk.

[morcey2]

I can't speak to the JJ GZ34, but I've used dozens of their preamp tubes, probably 20 pair of 6V6S, a couple of pair of KT77, and 2 pair of 7591's and I've never had a problem with them other than one ECC803S that I'm pretty sure I dropped. It got a nice white power getter after about 10 minutes and had a tiny crack in the glass at one of the pins.

Matt

[M Fowler]

Since I have limited brand to choose from in my town they carry GT so that is what I use a lot. I have ordered and used a lot of JJ tubes and to this date I have had no problems with their tubes. I do buy from good sources so maybe they test everything for us I do not know that answer.

All across the forums you hear a lot of bad things about every brand out there so I rely on my own experiences.

Mark