Anyone Else Have Trouble With JJ Tubes?
- Thread starter Azriel
- Start date
You've had a couple min BT that were very tempting.Find an amp that uses 6L6s.
Actually, that's not really a joke. Given HOW MANY 6L6-based guitar amps there are, and probably always will be- and HOW MANY DIFFERENT manufacturers make them- it's unlikely that we will ever have a time, where there isn't at least one or two companies making good, high-quality 6L6s.
Regards,
Gordon.
Destructor
Super Member
years ago I bought a JJ 5AR4 along with some other small items mostly because I needed to meet the minimum order requirement. I took one look at the pins, put it back in the box and forgot about it. This past weekend I was going through some tubes, came across it and just threw it in the trash.
GuyNoir
Hallowed State
In that amp, the power supply was of the switching type...it could have more robust. I'm not particularly worried about the JJ rectifier I have in my amp now. One reviewer who gigs with his guitar amp year round said he gets two years out of them, whereas Sovteks last 30 days tops. BS? Maybe. It seems there are just as many success stories as there are failures, and people no doubt shout loudest about dud tubes.
Destructor
Super Member
JJ’s 2A3’s and 300B’s seem to have a good reputation. I had JJ 300B’s running since around 2000, I finally just replaced them. One was beginning to make a bit of noise. After researching I replaced them with a new pair of JJ’s which are working just fine. There DHT’s have a good track record. The rectifier I chucked I would never plug into a socket, the blunt pins look like they would not be good being forced into a vintage socket.
Tom Bombadil
AK Member
I have a few JJs, a couple of KT77s, GZ34, and 5U4GB. Haven't used them a lot, maybe 100 hours on the GZ34 and a bit less on the KT77s. No problems and they sound fine. But not enough usage to form a strong opinion.
crispycircuit
Super Member
Sometimes you have to give another try because of the price. And cross your fingers!
I just lost a JJ KT77 yesterday. I've had them in use for about two years. I probably averaged about two to three hours every other day. I've posted about how good they sounded in my ST70 in the past. But, I don't think I'll be buying a replacement JJ. They definitely should last longer. I gave them a try due to a lot I read about quality control had gotten better. After burn it the bias has stayed steady with them. Until one started flashing at the base and then the channel dropped out. Switching channels confirmed it was the one tube. I'm using a set of '88's while I order a set of Gold Lions. Its too bad since the JJ's do sound pretty darn good for the $$.
GuyNoir
Hallowed State
I did just wreck a JJ rectifier, but it was my own fault. I quick-cycled the amp, and it blew a fuse. Suspecting the GZ34, I swapped in an RCA 5V4GA fatboy I had in reserve. I won't do that again!
Still looking forward to getting a quintet of ECC803 JJs at some point.
Still looking forward to getting a quintet of ECC803 JJs at some point.
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kmolles
Active Member
I do really like their 6BQ5/EL84's.....I had one quad in an amp that I play constantly for about 4 years....the only reason they were replaced was because of the earthquake we had in Napa a few years ago and things from an overhead shelf crashed down and smashed them. I replaced with another quad and no issues. I do have a quad of E34L's in a Dynaco ST-70 that I am apprehensive about (although I hardly use it).
crispycircuit
Super Member
This could be a long thread...
Here's my experience with JJ EL34's and 6CA7's. I have found some EL34's which would go completely dead after a period of time and will not even read anything on a tube tester. In order to understand why this happened, all I had to do was look inside the tube near the pin connections a see that the lead from the cathode to the pin was broken. On one tube it was the weld to the pin, on the other tube it was the weld to the cathode. In either case, the tube will not pass any current. The reason these connections broke in the first place is that the little "ribbon" from the pin to the cathode was perfectly straight and probably had some tension on it so when it heated up or was stressed even the slightest bit, it popped loose. This is strictly a quality control problem within the JJ plant where these are made and has nothing to do with the vendor I bought them from.The ribbon lead should have a little slack or small bend in it to allow for some movement. Otherwise, these tubes worked just fine until the failure. I tried to get the attention of the supplier (antique electronic supply) to make them aware of the obvious quality control problem so they could complain to the JJ distributor, but this fell on deaf ears.
I had a JJ 6CA7 do exactly the same thing. This tube was part of a matched quad I installed in my CJ MV50. So this wiped out the use of an otherwise good set of tubes and now I have a good pair and a "widow". I did replace all 4 with a new quad of JJ 6CA7's, so good so far after 2 years. These tubes sound great as long as they don't fail mechanically. I have had great success with JJ 6L6's, I must have over 60 of these in various amplifiers. The max voltage on any given pair might be around 500V in a blackface Bassman head. I have also run a cross 3 or 4 6V6's which would not read anything on my tube tester. These had another interesting quality control problem ... there was no thorium coating on the cathodes hence no emission either. I wonder how the hell these even made it out of the factory????
Lowtone
I guess that the vendor will replace those tubes ?
linuxslate
Well-Known Member
I think you are supposed to use Reflektor 6p14p's in that particular application. From what I have heard, the stuff on the shelf would not have stood a chance!
tonyg88
Super Member
Do you know about the newer Tung-sung 7591? They are pretty much an exact copy of the old production tubes. I had JJ 7591 before and they sounded pretty good. I liked the blue lights that would dance to the music.
