Faulty new JJ Valves

stevesuk · Post by **stevesuk** » Sun 08/16/09 2:28 pm

Unfortunately I have had 5 faulty JJ valves straight out of the box in the last few weeks. My supplier will replace them, but it has cost me time.

ECC83's (12AX7's) and EL84's.
Hissy and completely dead ECC83's and red plating and crackly EL84's.

Unfortunately due to their reliability in the past I have wasted a lot of time looking for faults when it was brand new valves causing problems.

I do get through lot in a week and I have never ever had any problems with JJ's in 5 or 6 years.

Anybody else having problems with JJ's ?

I just hope it is a bad batch, because up to now I have found them to be reliable, hardy and an excellent sound.

Steve UK
www.valvepower.co.uk

guilds100 · Post by **guilds100** » Sun 08/16/09 3:46 pm

I had a jj rectifier quit in my jtm 45 after 6~7 hours of use. I immediately pulled the jj power tubes as I figured they may go next. I've replaced them with tung sols and crossed my fingers and toes for luck.

BackwoodsJoe · Post by **BackwoodsJoe** » Sun 08/16/09 6:32 pm

I just had an issue with a 6V6. I was installing JJ 6V6's in a new build and heard a slight pop. The filament had "opened" on one of tubes. Next time I'll use an old tube the first time. Anyhow those tubes have been on the shelve for over a year, so there goes a set of matched 6V6's. Anybody else had this happen? joe

morcey2 · Post by **morcey2** » Sun 08/16/09 11:48 pm

I've only had issues with 2 JJ tubes and I've used lots of them. One was a GZ34 that died when I tipped the amp backwards to get the cord out from under the front of it. A few fireworks, a blown fuse, and a toasted rectifier. I guess they really mean it when the talk about the orientation limits, they really mean it.

The other one was a EZ81 that my grandson got a hold of and cracked. I didn't notice the crack until I fired it up and the getter went nice and white rather quickly.

I guess if I paid closer attention, I'd probably find some questionable sounding 12ax7's but I've been pretty happy with them so far. Then again, I haven't had to buy new ones for about a year.

Matt

guitarmike2107 · Post by **guitarmike2107** » Mon 08/17/09 2:45 am

I have had a JJ EZ81 die on me after a few hours of playing, and have had a couple JJ EL84 valves die after a short while, but they were running very hot.

Not had a problem since.

Mike

guilds100 · Post by **guilds100** » Mon 08/17/09 2:38 pm

morcey2 wrote: I guess they really mean it when the talk about the orientation limits, they really mean it.

Matt

Mine died with the amp sitting almost upside down while I was re-biasing. I may have killed it putting it in that position.

Post by **zaphod_phil** » Mon 08/17/09 5:02 pm

Not unless there was something wrong with the tube in the first place.

Brewmaster · Post by **Brewmaster** » Mon 08/17/09 8:48 pm

I had one JJ EL84 that red plated ( in an 18 watt) and two where the tip was "decapitated" (36watt) both about a month ago. The tubes were new in both cases. I checked both amps and everything was fine.

The amps are running with no issues but I put TAD's in both right now.
I guess some bad batches made their way through QC, something that wouldn't get picked up during burn in.

doctornorbert · Post by **doctornorbert** » Mon 08/17/09 9:58 pm

I had a JJ ecc99 that failed straight out of the box (sounded awful). The supplier replaced it, and the new one worked fine.

JoeK · Post by **JoeK** » Thu 08/20/09 6:29 am

out of 20 recent valve/toobs from JJ I've only had a bad 6V6 that was noisy as. I guess that's 5% but it is disapointing isn't it. Maybe it's a matter of what happened to the tubes after they left the factory. They are very fragile and overseas flights can't help. Europe-North America-Australia

luke1236 · Post by **luke1236** » Thu 08/20/09 7:56 am

I think i just had a brand new jj 12ax7 go microphonic on me. once i know for sure i will let you know but i am 99% sure

neon333 · Post by **neon333** » Thu 08/20/09 6:12 pm

luke1236 wrote:I think i just had a brand new jj 12ax7 go microphonic on me. once i know for sure i will let you know but i am 99% sure

I found that the JJ 12ax7's went "micro" pretty fast. Plus, they sounded awful in my amp (trinity sIII TMB), very brittle, harsh and glassy. I switched to the new TS pre's and am a very happy player. The TS tubes sound great and I've had not a hint of them going "micro" in 18+ months. BTW, I play at least 2 hours per day, so the tube have had a workout.

BDC · Post by **BDC** » Thu 08/20/09 11:38 pm

I pulled out a JJ 12ax7 in the PI and reinstalled it with the amp on and burned out the tube instantly.......no fire works...but I don't do that anymore

I had a some jj el84s in one of my amps that I ran red plating about 20 minutes or so while testing things in the amp...After adjusting the cathode resister and getting the idle reasonable one of the el84s burned out within a couple hours of use......I replaced the one tube and have ran the amp probably 50-75 hours since with great tone and no problems.

Both of these issues were probably my fault..........

There was no returning the tubes since i'd had em' sitting around too long..I much prefer the 12ax7 EH to the JJ.

Otherwise JJs have been good to me.........In the future I'll be trying thier 6v6s....

stevesuk · Post by **stevesuk** » Fri 08/21/09 1:22 pm

I am sorry to report, I have had another JJ EL84 redplate on me straight out of the box.

I have returned the first faulty batch to the supplier and they will trace them back to the factory batch. I will do the same with this one.

Steve UK
www.valvepower.co.uk

Gearfixer · Post by **Gearfixer** » Fri 08/21/09 6:30 pm

I have got bad JJ-12ax7s from TTS and CE D. Just one out of 12 were bad from CE and one of 6 from the tube store both replaced them quickly, this was just in the last 3 months or so. I have purchased at least 50 of them in the last 3 years prior to that and none of them were bad and all are still going strong.

I also got a bad set of 6L6s from TTS once.

Post by **rjgtr** » Fri 08/21/09 9:07 pm

I've only had a couple bad JJs in lots of years of using them. I've also had some bad Sovtek/New Sensor tubes. I've even had bad NOS tubes.

But I'd have to say the only consistantly unreliable tubes I've had were the Groove Tubes Mullard 12ax7 clone and the Ei ECC83s. Both sound great, but the failure rate is extremely high.

I like the new TungSol 12ax7s and am about to try the new NS Mullard 12ax7s. I still like the JJs, but I've found some amps like certain tubes more than others. I've yet to find any new production tube that works in every amp. Even some NOS tubes work better than others.

stevesuk · Post by **stevesuk** » Sat 08/22/09 2:14 am

Gearfixer wrote:I have got bad JJ-12ax7s from TTS and CE D. Just one out of 12 were bad from CE and one of 6 from the tube store both replaced them quickly, this was just in the last 3 months or so. I have purchased at least 50 of them in the last 3 years prior to that and none of them were bad and all are still going strong.

I also got a bad set of 6L6s from TTS once.

This post points toward a possible quality control problem at JJ.

Like Gearfixer, after using hundreds over the years without a single problem, suddenly a percentage are bad.

Steve UK
www.valvepower.co.uk

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