Remember back in the beginning of January when I traced the failure of the Lacewood amplifier to a failed JJ power tube? Well, here we go again.
Another JJ power tube went south on me today. This one was a 6L6 in the Spalted Alder Amplifier. Luckily this time the failed tube just died and didn’t try and fry my amp at the same time. But it is yet another JJ power tube to suffer premature failure in the last six months or so. This one just quietly had the heater open up.
Shorts, opens, buzzing, crackling, flashover,… Just what in the world is going on with JJ power tubes? I checked, and the failed JJs I’ve received in the last year have come from three different suppliers. This isn’t a reseller issue, or a bad lot, this is something specifically wrong in the JJ factory making 6V6S and 6L6S tubes.
I’m done buying JJ power tubes for a while. It’s not that I’m really angry or anything. It’s just frustrating when a product which has worked well for you for years suddenly goes south in such a spectacular fashion.
As always, questions and comments are welcome.
Follow Up – 14 July 2025
I heard back from the folks at JJ in the Slovak Republic. Evidently there is not any systemic production or quality problem of which they are aware. They also responded with:
But, in any case, we are surprised by your email, because recently there are minimal complaints about quality of JJ vacuum tubes …
So it looks like it’s either something I am doing or I got a batch of counterfeit tubes from one of my suppliers. Unfortunately I no longer have most of the failed tubes in my possession. I will investigate further as much as I can. However at this point I am refraining from making any specific recommendations except for people to keep track of where they purchased individual tubes so that systemic problems can be tracked.
Right now, the only JJ power tubes I have in regular use (daily) is a couple of 6L6GCs in the Spalted Alder amp. I’ll keep an eye on them. And I remind everyone that I have had no issues with any other JJ tubes. The signal tubes and rectifiers are great performers with seemingly long life.
Regards.
My experience with JJ is that their GZ34’s are like little time bombs in your amp!
Well; I’ve sent an email to JJ describing the situation and asking for whatever information they may have. We’ll have to wait and see how they respond.
Uff-Da. I have a bunch….I mean a bunch!…..of JJ EL-34’s. Not a single amp that uses them though……..?
Bought them cheaply with horse trading in mind. Now I’m a little leery.
I also have a pair of JJ EL34s which I haven’t used yet. I intend to put them in a test jig for careful burnin before I put them into any amplifier.
I wonder whether worthwhile sending of an email reporting the failures. If they value their reputation and stand by their product such reports could be useful in identifying batch problems etc. It would be an opportunity for them to keep the customer onside with the offer of a replacement tube particularly if they are aware of quality issues.
Saluti da Palermo
Si anche io sono d’accordo di effettuare una segnalazione direttamente alla JJ.
Così che possano prontamente intervenire su possibili bug di produzione, dobbiamo anche considerare che,nel frattempo anche altri costruttori sia a carattere hobby che industriale utilizzano tali valvole
> Greetings from Palermo
> Yes, I also agree to report directly to JJ.
> So that they can promptly intervene on possible
> production bugs, we must also consider that,
> in the meantime, other manufacturers, both
> hobbyist and industrial, use these valves