How to test tubes?

[shadow070]

I've had a sixtet of El34 Sed winged-C Tubes, After 2 months one blew.
That i got a sixtet 6550 Sed Winged-C tubes, after 4 months a view blew.

How can i test iff the remaining ones are ok?

I retubed the amp again with mixed tubes, but i still get a volume drop. i swapped the tubes 3 times already last week. This means that 2 pairs off 6550 tubes went bad.

Ip hope that there is a easy alternative for checking the tubes.

 

[steve_k]

I've had a sixtet of El34 Sed winged-C Tubes, After 2 months one blew.
That i got a sixtet 6550 Sed Winged-C tubes, after 4 months a view blew.

How can i test iff the remaining ones are ok?

I retubed the amp again with mixed tubes, but i still get a volume drop. i swapped the tubes 3 times already last week. This means that 2 pairs off 6550 tubes went bad.

Ip hope that there is a easy alternative for checking the tubes.

Got to buy a tube tester and know what you are doing. Not very practical. But, why not just order 3 pairs of matched pairs? I assume this is going in a Herbert? You don't need to order sextets.

First thing though, maybe order through someone different and let the person know that you got the tubes from what happened and that you aren't happy. They will probably say that it isn't their responsibility, but then again they may be nice and warranty their work. Knock on wood, I have never blew an SED.

Are you sure you got everything biased correctly. You could be running them on the high side of bias. When you change tubes and bias, burn the tubes in for a bit in run mode and the volume cranked (without a guitar plugged in unless you have some really cool neighbors) and leave the back grill off and look at the tubes. If tubes are running hotter than their range, they will glow red down the glass. When putting the 6550's in the Herbie, turn the bias screw all the way left then just a short curly to the right. It is very sensitive to adjustment on the 6550's.

Steve

 

[shadow070]

Steve,

Thanks for the info. It was not a sixtet, my mistake. They where 3 pairs. Right now im tired off it. Ill just order 3 pairs again. Im going el34 sed winged C again.

The tubes left from the previous two times, these ill bring to a tube specialist here in town to check out which one is good. Total 12 tubes, i think about 3 are broken, so its a waste to not use them anymore, ill have them as backup.