J/J tubes. JJ must stand for Just Junk.

[StratmanR2S]

I've had my new Lynch Box combo for three weeks and One of the J/J EL34 tubes has already shorted out. The bad tube blew a fuse and when I replaced it and tried to bias it, it was reading 10mv lower than the other and I could see the voltage intermittently spiking.
I put in a pair of Russian Grove Tubes I've had for years and its back up again.

I put some J/J EL84's in another amp of mine a few years back. they worked OK, but they rattled so bad I had to take them out for recording. Once they were out I found that the Sovtec's I had in it before sounded better so they never got used again.

I know your results may very, but these are my two experiances with J/J's and to me they are Just Junk.

 

[Julia]

JJs are as durable as any other tube out there. I'm not totally sold on their tone however, but I also find their preamp tubes to be pretty darn good in some applications especially when I don't want a bright tone.

I've never had a set of tubes that come with an amp last any length of time. You gotta remember the amp was probably dropped a few times by UPS or however else it was shipped. That will jar stuff loose in tubes. Also I know of tube dealers that absolutely refuse to ship tubes UPS because of the way they treat stuff.

 

[StratmanR2S]

Yeah I agree, shipping can be rough, but this amp is expected to get moved around constantly to gigs and rehersal so it probubly would have went out either way. I like the sound of the old Russian Grove Tubes EL34's I got in there now better anyways.

I know a amp repair guy who swears by JJ's, but for my money I think I'll use other tubes.

 

[Zander]

If I were doing the moving that you say you're going to be doing I'd consider pulling the tubes from the amp every night after each show and putting them back into the amp after arriving at my next one.

Shouldn't be too hard to get a light carrying case, cut out foam to fit inside said case, cut out slots in the foam to fit the various tubes, and then label the slots so that the same tubes go back into the same sockets every night...

 

[StratmanR2S]

I've never had tube issues before by moving my amps, and don't expect any in the future. They aren't that delIcate. This was just a bad tube from new.