Rectifier for 1979 fender champ silverface 5ar5 (gz34) or 5y3?

[goldTopDeluxe]

hi amp experts. total newbie here. .I've just gotten hold of a 79 champ that is supposed to be all original. It has a 5AR4/GZ34 in the rectifier, but according to the fender
amp field guide, and from what i can tell by looking around on the net, these champs were supposed to have a 5y3 rectifier. In fact, the label in the cab specifies 5y3gt for the rectifier.

I should mention as well that I'm in Australia - and the stock label on the back says 200/250 volts. Everything in Australia here is 240 volts - so would that explain the 5AR4?


I have a few spare 5y3 tubes from another amp lying around that I'm itching to try out - but to be cautious, thought I'd ask here first before I damage the amp.
Should I just go ahead and swap the 5y3 in? Or is this a bad idea? And if I were to swap it with a 5y3 - what should I expect sonically?

On the flip side, any reason why I should keep a 5ar4 be in there?

thanks.

[Gtr_tech]

The 5Y3 is what should be in there. The GZ34 will drop less voltage and your b+ will rise because of this. Champs should be using the 5y3 unless modified to use a different output tube.