How do I find out if my tubes are good?

[anomaly]

I've got about four sets of old 6l6's, Mesa branded and JJ's. I'm just wondering if there is any way to test them in a amp without damaging the amp in any way? like blow a resistor or something? I'm positive some of them are still good, but i'm also quite positive that some are no good.

 

[Racerxrated]

I've got about four sets of old 6l6's, Mesa branded and JJ's. I'm just wondering if there is any way to test them in a amp without damaging the amp in any way? like blow a resistor or something? I'm positive some of them are still good, but i'm also quite positive that some are no good.

If you don't want to spring for a tube tester, then you'll have to put a tube in the amp and see if it blows a fuse...in theory that fuse protects the transformers. But, I don't want to say for sure that a bad tube wouldn't possibly take out a transformer...Before I got my tube tester, a bad tube would just pop the fuse. But maybe I got lucky...

 

[Racerxrated]

Here's one for 250...

https://reverb.com/item/66300026-conar-model-223-tube-tester-with-200-free-tubes

 

[Racerxrated]

Here's a cheaper one...

https://www.ebay.com/itm/1157188533...piFJrTPhAKZBVhc1r7ouktzEg=|tkp:Bk9SR8y0oqrTYQ

 

[thegame]

If the tube says JJ it needs to be replaced by a tube that doesn’t say JJ

 

[70 Mach 1]

The uncle fester way.
Put it in your mouth and see if it lights up.

What happened to the tube tester machines that were in every drug store

 

[Diary of a Axeman]

The uncle fester way.
Put it in your mouth and see if it lights up.

What happened to the tube tester machines that were in every drug store

Last time I seen a tube tester at a store, was in 1985.
But Euro tubes sells some tube testers .