[eichlerera1]

I've used the JJ E34L tube in my VTL 225s since they first came out.
It has a bad reputation as an unreliable tube with a fairly high failure rate.
I've had the tube produce some lovely firework shows in the upper section.
But, in fact, most of the failures occur at the bottom of the tube.
That said, I believe the current crop of JJs are somewhat more reliable.

The dilemma is that the tube is cheap and when it is in working order produces some great sound!
Great tight bass. "You are there" midrange. Highs that are not etched and fatiguing.
Unfortunately, the two Mono Block VTL 225s use a total of sixteen output tubes so tube rolling would be an expensive proposition!

So I look at it as comparable to owning a Jaguar XKE.
In the shop too much and having to deal with the crummy Lucas Electronics and messy oil leaks.
My method to deal with it are as follows:
Almost all of the failures manifest themselves during initial startup.
So I have an inline two position switch which initially feeds the amp 75 volts.
I let that percolate for a minute or so and check for any suspicious arcing or speaker sounds.
If OK, I'll switch it to the shorted 120 volt position and repeat my checks.
Any signs of a problem I quickly switch off the amp and simply replace the tube.
This happens about every six months and so far the bad tube has not taken out any resistors.
I figure a 5 minute startup is worth the small hassle.

Is the failure rate too high?
Hell yeah, but the sound is worth it!

Feel free to relate your experiences with this finicky, but outstanding tube...

[FullRangeMan]

JJ are know to dont perforn QC in his tubes, a bad tube can made a fire in a tube amp and may spread to room, there are other great sound EL34 builders.

[eichlerera1]

JJ are know to dont perforn QC in his tubes, a bad tube can made a fire in a tube amp and may spread to room, there are other great sound EL34 builders.

I hear you FRM, but when this tube is functioning right (most of the time), the synergy with my 225s will bring you to tears...

[Tom Bombadil]

Haven't used their EL34, but have had good experiences with the JJ KT77.  Sounds pretty good, no failures.   My amp was built by Dennis Had, of Cary Audio fame, he told me that he very much likes their KT77 and ships it as the stock tube in some of his amps. 

Personally I like the new Gold Lion KT77 better, but by a slim margin. 

[FullRangeMan]

There is a New Sensor EL34 Mullard reissue made by Reflector at low prices.

[luisb]

Hi
I like Tung-Sol EL34B very much.  I have a pair of old Audio innovations 1000 mk 3 monoblocs.  I had great sound with Winged C Svetlanas, but they were always failling, even when i modified the monoblocs with a tube bias control (tentlabs).  The Tung-Sol had no failures in the last 6 months and sound almost like the Svetalanas.

[Tyson]

I think modern production tube sound quality has improved across the board.  Particularly over the last 5 years or so.  So the new Tung Sols sound a lot better than when I first heard them 15 years ago.  Same with the JJ tubes.  Gold Lion has always sounded good. 

But the biggest surprise for me is how good the Chinese tubes sound.  The Shuguan Black Treasure tubes and the Psvane Titanium and Western Electric replicas are all outstanding sounding.  And reliability has improved quite a bit in recent years.  If you've not heard these tubes for a while, give them a shot.

[richidoo]

E34L is different from EL34, but compatible. E34L was designed by GE with more power than EL34.
Several decades back Groove Tubes licensed the design and bought the machines and materials from GE.
They hired JJ to build the tubes and sent the equipment to them.
The first batches of GT E34Ls from JJ were excellent.
So excellent, that Mitch Margolis who was on the Groove Tubes E34L team and on the Manley Labs design team, designed a new Manley amp specifically to use this tube, the Snapper. It made an honest 105+ watts from 4 el34 type tubes and used a custom, in house OPT it could handle low impedance speakers with ease. A friend commented on how strong and tight the bass sounded for a tube amp. I had Usher Be20s then, and I remember some amazing peak listening experiences with Snappers.

But good things never last forever, and soon JJ was shipping junk. Manley has rigorous tube testing facilities and rejected a lot of them. But things didn't improve, so Manley designed new tube testing equipment and changed the testing plan to try to filter out the shit, but they couldn't. I retubed after 2000 hours with fresh set of GT E34Ls and 3 of them exploded. Manley replaced them and repaired some damage the tube failures caused. They gave up on E34L and offered me a new octet of EH 6CA7 for free and I accepted. It was powerful sound but very warm and blurred compared to the extremely clear and concise E34L. I also tried at my own expense octets of JJ KT77, and cryoed Black Sable SED wingedC EL34. They were nothing compared to the GT E34L. Shuguang Black Treasure was just coming on the scene then with good reviews, and they had a 6CA7 tube, but it was very expensive and by then I was tired of the whole thing. I sold the Snappers and moved on.  A few months later a friend and favorite poster on AC mentioned he had 5 quads tucked away in his collection!    But that would only last me a couple years anyway. If those tubes were available again, I would buy new Snappers again in a heartbeat. I think JJ ran out of the original GE metal and switched to normal crap they use in cheap tubes but E34L design did not tolerate that.  Groove Tubes E34Ls still sold, but GT is now owned by Fender.

I use Gold Lion KT88 now (in a different amp) and they are excellent. The Gold Lion KT-77 reviews are good and I would not hesitate to try them but I haven't heard them myself. Definitely call to ask VTL what they recommend.

[SteveFord]

If the people at VTL make you want to reach through the phone and throttle them, here's what Manley is using nowadays:
https://www.manley.com/hifi/msn