JJ 6L6GCs... WTF?

[Chuck H]

Now that RCA is out of the business the 6L6 standard no longer has an enforcing body to ensure strict compliance with the old specification.

Agreed. And this has presented itself many times with new production tubes. There are even references such that someone will state "best 6l6 style tube" or something like that. And that may be the best we can hope for. But to be sure WE are the "enforcing body". If we don't buy a tube it stops being produced. How many dozens of Russian big bottle incarnations have come and gone in the last decade!?! And IMHO they are sounding and performing better than they use to. With this recent dip in QC throwing a big wrench in the cogs. But trust me. If we all start buying Chinese tubes the distributors of Russian tubes will improve QC. I tried, but got microphonic tubes anyway And I can't return them because I "saved" ten bucks buying from a vendor that I later found doesn't honor the incredible six month warranty that usually accompanies Ruby power tubes. I'll be buying Ruby's again to replace them, but I'll be purchasing through a different vendor.

[km6xz]

Wouldn't it be easier to just buy from Magic Parts so you get the warranty?

I shouldn't jinx it by mentioning it but over the last 12 months, not one EH 6L6, EL34 or 6550 installed in a repair has come back. That is a complete reverse of past results. Something has changed but maybe it is just luck. Still, the only power tubes I have learned to be fully confident in are old Soviet era 6П3с-е tubes that seem bullet proof. They are lower gain and not suited for metal players but for blues and general play, they are the preferred tube from a repair perspective. They are very close to the 5881 of old.

[tubeswell]

... Still, the only power tubes I have learned to be fully confident in are old Soviet era 6П3с-е tubes that seem bullet proof. They are lower gain and not suited for metal players but for blues and general play, they are the preferred tube from a repair perspective. They are very close to the 5881 of old.

That's what I put in my 6L6 amps. They're still reasonably priced too.

[jbltwin1]

OK-am I just stupid of is there something going on? The front page says that last post on this topic was at 4:04 am TODAY but the thread doesn't show up here. It has three pages of responses and I go to the last page and the last thing there is from july. I scan the section that says more posts below this line or something and it gets it up to the 15th I think. STILL no current post. Are they leaving or am I just not seeing them? Mike.

[tubeswell]

The way the website software organizes replies to threads in the summary tree/directory means you have to click on the More replies below current depth... link in order to see the replies that don't fit on the summary tree thingy. If in doubt holler to T-boy

[g1]

I scan the section that says more posts below this line or something and it gets it up to the 15th I think. STILL no current post. Are they leaving or am I just not seeing them? Mike.

Things are much easier if you set the thread display mode to Linear, either oldest first or newest first, your choice.
Go to settings> general settings> thread display mode.

[big_teee]

Back to 6L6 Tubes.
I just bought a new set of TAD short bottle 6L6WGC-STR for a new amp build.
I can't say enough good about these tubes.
They sound great!
Not Dark sounding like so many 6L6 tubes IMO.
Nice Compression.
I bought them from MojoTone.
T

[jbltwin1]

Yup-linear display cured it. Thanks. Thought I was nuts! Mike.

[km6xz]

Yes, very reasonable. I get them here for 100rubles, about $3 and sometimes if someone has a surplus of them at the electronics flea market, I get new NOS for $1. They were used in everything from military gear to TV sets. There is another version, the 6П3с, that looks the same but is not as robust, sort of a super 6V6. That series of Soviet era tubes got the rebranding crazy going 20 years ago. Groove Tube and Sovtek were build on getting those for $0.30 or so and putting various 6L6 labels on them.

There are some interesting low power beam tube, in the 20-60 watt plate dissipation range that seem to be popular with home builders for hi-fi. A retired Svetlana engineer who now has a small consulting business for high voltage systems(>60kv) cleared out his little workshop located in a small bedroom of their apartment and gave me his collection of vacuum tubes, probably a couple thousand, all new, most made by Svetlana 20 + years ago. So I have a large selection of interesting tubes I had never seen before in addition to the common operational substitutes used now for 12AX7, EL84, 6L6 and a rare version of EL34. He threw in a lot of tube sockets for the strange pinouts and size bases. One project I need to finish so I can experiment more with these is the tube lab power supply. I have a tube regulated supply by home that gives variac varied, metered B+, Variable, metered C-, Mini-variac variable metered Screen supply, 6.3vac non-metered and 5vac non metered. That one is too heavy to bring here in a suitcase. So I have been slowly collecting parts for a similar unit but using a switching supply for the 5 and 6.3. A regulated C- simplified supply and a single HT supply with a tracking regulator tap for screens. The whole thing will be much smaller and 1/2 the weight of the lab supply. I got a bunch of cheap Chinese digital panel meters for current and voltage for each supply. It sure will make quick and dirty idea testing a snap. I got a 300CT transformer with a lot of current reserve that will be powered the spare 800VA variac I have. That will give me my desired B+ range of 0-600 plus. Variable circuit breakers have already been built for it. I'll post photos when I get it done.

[Oldmanbluez]

I wanted to add that I have had problems with JJ6l6's and rectifier tubes for over a year. I went through a couple of matched sets and GZ34's before I found usable tubes.
When you are a small potatoes tech like me you can't afford the reliability issues so I have gone to TAD and have had zero problems. I also have had luck with Tung Sols 6l6 but I
have noticed they don't like higher voltages.
Anybody have any idea where TAD is sourcing their small bottle 6l6WCG-STR? They sound great and I have had no issues at all. Same with the TAD rectifier tubes.

[pdf64]

China, see last post on Who Makes a Good 6L6 Tube? - Page 2 - The Gear Page

[The Dude]

Another new Mesa in the shop today. "Express 5:25"
3 of 5 Mesa preamp tubes totally bad.

[Jazz P Bass]

As it is rare for three preamp tubes to go bad, you cannot really blame Mesa can you?

[bob p]

if 3/5 preamp tubes are bad in a new amp, then i'd say that somebody's having QC problems -- either that or you've got a customer who is extremely hard on his gear.

maybe he's a serial unplugger. it's easy for a ham-fisted brute to damage preamp tubes, you know. it wouldn't surprise me if 3/5 of the OEM tubes went bad after the new owner decided to start "tube rolling" and damaged some pins during the process.

as i read this thread, i'm reminded of the ads with the photo of the rubber mallet where Mesa said that they test every tube that goes into their amps.

so how "new" was the amp? it's hard for me to think that someone like Mesa could screw up this badly by putting dead tubes into a new amp. I'm thinking that the amp had to be good when it was demo'd and sold, or nobody would have bought it. so now you have to consider what would make the tubes experience "sudden death" right after the sale.

i'm more inclined to think that the user did some tube swapping and doesn't want to talk about it now that he's broken the amp. i've seen some amps with REALLY tight noval sockets, like my pair of SVT-2 Pro. It's so hard to get the noval tubes out of those amps that I'm worried about tube destruction every time that I remove them for testing.

[The Dude]

Fellas,

I'd be inclined to agree with you, but this happens pretty consistently in my neck of the woods, even with brand new off the shelf Mesa tubes that have never been in an amp.

Jazz P- I do blame Mesa. They are the only tubes sold in my area that are more consistently bad than good. Whether it's bad QC, factory seconds dug out of a dumpster, shipping problems, whatever is not relevant to me. All I care about is the fact that they have a high failure rate even brand new. I'll leave it to someone else to determine why.

bob p- I'm told the amp was only used a couple months and not heavily. The tubes and sockets showed no signs of tampering or incorrect insertion. Also, like I said, I get the same thing with off the shelf Mesa tubes (unused). I have the amp apart right now and the socket pins are soldered well, voltages are normal, and pins are good. After talking to the customer and an inspection of the amp, I can find no reason other than crappy tubes that this happened. I should also mention that this happens VERY consistently with Mesa tubes- so consistently that I will not buy or sell them. Unfortunately, I have a few customers that bring in their own tubes with the amp.

Edit: Forgot to mention. This amp belongs to a Dr. who's a closet guitar player. It's never been gigged with. He just fiddles at home.