RT2/50 problem..

[Pseudosam74]

Been using this with a Rocktron Voodoo Valve with great results for awhile now. I switch between the two RT2/50 channels to coincide with different patches.
Took it on the road for a few days. Worked like a charm the first few shows. Then, it gave me a "tube fault" light on one tube in channel two. I looked back, and that tube was indeed running incredibly hot. I dropped in a pair of replacements on the fly. Didn't bias it.. but it was a matched pair of the same type (EL34s) so I figured it would be fine for the two remaining shows. However, it immediately gave me TWO tube fault lights for channel two. Since these are new tubes, I know that it's not their fault. The lights go off when I go into standby mode.
Ideas?

 

[JKD]

Check the fuses first

You need to bias it...unless the tubes were the same type and matched to the ones you replaced, chances are they were either hotter or colder and could have drawn more current/caused the fuses to blow...

If it's not the fuses then the tubes maybe took a resistor out...the fuses are supposed to blow first tho.

 

[Pseudosam74]

I will definitely check the bias. The problem though is that before I replaced the pair one of the tubes failed. That's why I replaced it. The fact that a second failure occurred, both with an old pair that was working fine and a new matched pair, is what troubles me.

 

[GtrGeorge!]

but that just wants me to check the bias even more.
I had a tube failure light go one last year..turned out it was the bias. I made the adjustment...light went away..life is good again. I kept using the same tube..but it had drifted out of bias,thats all.
... thats what happened to me.

 

[Pseudosam74]

Ok. Will check it tomorrow. I just looked at the fuses and they did indeed blow. Actually the last venue we played was pushing way too much power. I"m sure that's what did the second pair in. I'm just curious as to why both failures were on the same channel and not the other. Hopefully it's biasing.

 

[JKD]

If it was EL34s then all tales tell they are unreliable of late....

Im no expert but if the voltage was up 20% then you'd be running pretty hot I think...

 

[Jaded Faith]

Check the fuse rating as well. The older amps came stock with 250ma fuses and you should be using 400ma fuses in there. The 250's would blow quite easily in the first RT2/50 I had years ago.

 

[Pseudosam74]

It had 400 fuses in it. All I could find to replace are 500ma. That's ok, right?

 

[Jaded Faith]

400ma was what was stated, but I know of several of us who have used 500ma's for quite a while without issue.