Modern EL34 reliability?

[Mick Bailey]

I use Belton sockets and they don't seem too bad. In my own builds I've used octal ceramic transmitting tube sockets and they're a much better bet than anything else. No pins are too big or too small - they have a separate clamping spring for each pin so the contacts themselves don't need to apply any force. Except they're huge by comparison to regular sockets and need more chassis space.

[Justin Thomas]

I'll get some next time I place an order.

Justin

[tubeswell]

So, the amp that blew up the (New Sensor) 'Svetlanas' was a 1959 Superlead 100 (a 2005 RI version hand-wired in the UK). The EL34 voltages were Vg1 -41.8, Ik = 35.1mA, Va = 507. This was after the amp had been warmed up for 25 mins.

The same customer bought in another UK made hand-wired RI 1959 SL100 (this one made in 2006), still wearing the set of complete factory-fitted JJEL34s (each tube dated stamped 2005). AFAICT, this is an identical amp to the 2005 one. I checked the JJEL34 voltages in this amp (Didn't bother fiddling with the bias): Vg1 -34.4V, Ik = 47.6mA, Vg2 = 472, Va = 482 (after 5 mins) - Idling at 22W! Whoa!. The customer claims he bought this 2006 amp brand new, has hardly used it, has never had a problem with it, and never touched the tubes. Even so, it seems that even the circa-2005 JJ EL34s can stand up to punishment better than present day New Sensor 'Svetlanas'.

[Chuck H]

I can't say if anything has changed, but two years ago I blew up two pair of JJ's in an amp at 475Vp idling at 18W. The moment I put the screws to them with some power tube clipping they shorted. I was starting to think it was the amp. I couldn't find anything wrong so I chalked it up to the usual, unusual likelihood of consistently bad power tubes and started asking questions here. That's when I bought the Ruby branded Shuguangs. The first pair was too microphonic for the combo amp I was working on, but the tubes survived. I ordered two more pair and they were also too microphonic. They also survived. Judicious use of silicone rings helped enough that I was able to ship. But the Ruby's survived where all others failed. I can't say if it was the vendors lack of testing or a decline in quality from JJ.?. I won't trouble with it again while I already know that a way around the problem is Ruby branded Shuguang tubes and silicone rings. JJ can screw off.

[bob p]

Please don't hold back on naming the suppliers who are giving you crappy JJ tubes, no matter who they are, and especially if they're someone who claims to perform their own QA screening.

The distributor's identity is key information to know because some suppliers claim to screen the their tubes while other's don't. Getting a bad one from someone who doesn't claim to screen shouldn't surprise anyone, but getting bad ones from someone who does claim to screen is an entirely different situation.

If a distributor screens tubes and rejects bad ones, those tubes have to go somewhere. if they're not being destroyed then they re-enter the marketplace somewhere else. Granted, that indicates that there is a problem with QC at JJ, but if there's a way to work around that by buying from the right guy, that's a better solution to me than dealing with microphonic tubes.

[Leo_Gnardo]

If a distributor screens tubes and rejects bad ones, those tubes have to go somewhere. if they're not being destroyed then they re-enter the marketplace somewhere else. Granted, that indicates that there is a problem with QC at JJ, but if there's a way to work around that by buying from the right guy, that's a better solution to me than dealing with microphonic tubes.

We've been round & round with the same subject a couple years ago here on MEF. At that time, IIRC the distributors that had the best rep for shipping no-problem JJ's were Eurotubes* and Mojo. Time's gone by, maybe the results will be different. And new vendors have appeared, like Doug's and Valve Queen. Also CE/Antique/Tubesandmore have changed their test gear and presumably improved their game. I'm looking forward to seeing our correspondents' reviews. Maybe a different thread should be started for this, or even a sticky where we can monitor the suppliers over the course of years.

Again, IIRC, Euro sells JJ exclusively, and offers no discounts. Let's hear about it if there's been any change.

[Chuck H]

Something to consider... I have suspected that there are some tube vendors operating under more than one web presence. If one is bad, the other most likely will be. I once bought two pair of JJ el34's and they sat around for four and a half months before I installed them in an amp. Both pair failed. I wrote the vendor and explained the circumstances. No dice. The tubes were beyond the warranty period... Period. This makes it impossible to stock JJ tubes unless YOU are willing to test them the moment you receive them before stocking. Even then you can't offer a warranty to a client without the expense coming out of your own pocket. At the very least negotiating these particulars means that you can't order tubes until shortly before it's time to plug them in so that if they fail you can return them. And then if you have to return them there is additional time added to the amp order while you complete correspondence with the tube vendor and wait for shipping BECAUSE YOU CAN'T KEEP INVENTORY. Not everyone that builds or works on amps can become a vendor just to keep tubes at hand without financial risk. So we get the risk. We accepted this begrudgingly. But now that many on line vendors are failing to cull bad tubes (particularly el34's) it's becoming VERY cumbersome. Putting this burden on the buyer is insulting and disrespectful. I've mentioned the name of the vendor responsible for my situation in a couple of other threads so I won't put them down by name here, but it rhymes with thelubestore. Which is probably a vendor site the proprietor should start and link because a stop there first might make the experience less uncomfortable

[tubeswell]

... I won't put them down by name here, but it rhymes with thelubestore. ...

[bob p]

I have suspected that there are some tube vendors operating under more than one web presence. If one is bad, the other most likely will be.

Sort of like CE-Dist selling to us with one hand, and also selling to end users as AES, TubesAndMore, and more recently, as Amp Parts Direct with the other hand? I never understood the need for their second or third retail presence. For all I know they have yet another one that I'm not aware of.

You have to wonder if a company that actually culls might invent another online presence just to dump their culls without effecting the main store's rep.

I once bought two pair of JJ el34's and they sat around for four and a half months before I installed them in an amp. Both pair failed. I wrote the vendor and explained the circumstances. No dice. The tubes were beyond the warranty period... Period.

BTDT. I agree it's a pita, but you have to consider that not every customer they deal wtih is like you or me, an honest builder or service guy who buys tubes just to shelf them for who knows how long until they're needed. There are presumably guys out there who will run the tubes and then complain when they fail later on, so the merchants try to protect themselves from that with a time limit. I'm not saying it's right, but it is the way the world works.

This makes it impossible to stock JJ tubes unless YOU are willing to test them the moment you receive them before stocking.

If you buy in bulk, you have to do just that. You have to set up your own burn-in and matching jig, and drive everything into a dummy load to find the ones that have to be rejected right away. I hate to say it, but if you're serious then you have to bite into the bullet.

Even then you can't offer a warranty to a client without the expense coming out of your own pocket.

To protect yourself, you have two options: build your own burn-in jig or stop providing warranties on tubes. I do both.

Sure, not providing a warranty is disrespectful to the customer, and we've been disrespected. We'd like to be the good guy who sticks his neck out by offering tube warranties, but in today's marketplace that just doesn't make sense. Why should we warranty something that the supplier won't warranty for us? IMO that's just bad risk management.

The result is that I do my own burn-in to protect myself at the time of purchase. I hate doing it, but I have to do it, so I do it. And to protect myself at the time of sale, I don't provide warranties on tubes to users. I don't like doing that, but like you said it's just not fair for us to have to stick our necks out providing a warranty when the supplier won't back us up. Because of this I explain to my customers that I don't make the tubes and because the people who do make them won't cover them, then I can't cover them either. I've found that by being honest and explaining the situation my customers end up being disappointed but accepting, which is all I can ask. I jokingly tell them that all I can offer is a tail light warranty on the tubes -- I'll warrant that the tubes are functioning properly and work fine when I install them and test the amp, but the warranty ends when I see your tail lights.

Realistically speaking, that's as fair as can be reasonably expected. Customers need to understand that you can't give them something that the manufacturer/distributor isn't giving to you... especially in the age when every customer has an attenuator and runs the amp on eleven, or when the amp gets tossed into a van right after the show, a keyboard gets thrown in on top of it, the whole lot gets shaken all of the way to St. Louis for tomorrow night's gig, then gets bounced on the loading dock, and plugged into God only knows what kind of electrical supply...

It makes no sense to provide tube warranties, so I don't do it. I think amp guys like us need to be honest with our customers, be up front and tell them that given the quality of the tubes today, the way that we don't get backup from our suppliers, and the way people are abusing them with attenuators, tube warranties just can't be provided.

I suppose that one way to deal with the problem for customers who demand tube warranties would be to sell them tube warranties a la carte. At that point you're actually selling an insurance policy, and you're acting like GC does when someone buys from them.

I tried to post another long ramble earlier this afternoon but the board spat it back at me with a database failure. There seems to be a lot of that going on lately. I'll try again.

[bob p]

We've been round & round with the same subject a couple years ago here on MEF. At that time, IIRC the distributors that had the best rep for shipping no-problem JJ's were Eurotubes* and Mojo. Time's gone by, maybe the results will be different. And new vendors have appeared, like Doug's and Valve Queen. Also CE/Antique/Tubesandmore have changed their test gear and presumably improved their game. I'm looking forward to seeing our correspondents' reviews. Maybe a different thread should be started for this, or even a sticky where we can monitor the suppliers over the course of years.

Again, IIRC, Euro sells JJ exclusively, and offers no discounts. Let's hear about it if there's been any change.

Yes, we keep going round & round. What's old always becomes new. I hate revisiting this topic as much as you do, but when someone pulls the fire alarm we still have to walk out of the building, right? Whenever one of these threads comes up we still read them, even if we only do so out of morbid curiosity.

Yes, we've covered this topic over and over ad nauseum, but that's the price that we have to pay for clinging onto technology that went obsolete in the 1970s, in an era where there's no longer any fierce high-end competition. On the subject of suppliers: new players come and go, and old players have to up their game to stay competitive, so we have to keep revisiting the topic. The way I look at it, that's my price of admission, so I just bite the bullet and read on...

The one thing that I don't like about this situation is when somebody gripes, but doesn't identify their supplier or doesn't provide complete operating conditions that lead to failures, and doesn't even attempt to identify the failure mode. "The tubes blew up" is a common complaint on many amp sites, but it's not quite the caliber of input that I'm used to seeing here.

Not identifying the supplier serves no purpose -- it's not as if we're protecting anyone by not telling each other where we get our tubes, and making that data point invisible only adds to the obfuscation of the problem.

Not providing the full operating conditions that lead to failures doesn't help either. That makes it impossible to figure out how to solve the problem at our end. In that regard, I guess I have to say that the people who don't provide operating conditions for tubes that don't fail are as guilty as those who don't provide operating conditions for tubes that do fail, when it comes to contributing to the ongoing obfuscation of the problem. Without that data we're left with anecdotes that don't really take us anywhere helpful.

Leo, my hat is off to you. Very early in this thread you keyed in on screen dissipation and gave specifics on what operating condtions might lead to failure and what steps could be taken to avoid it.

I'm having a bit of Deja Vu over this...

This reminds me of the days when the JJ 6V6 were earning a bad reputation for blowing up in Deluxe Reverbs. Anyone remember that? It had to be around the turn of the century. I was posting on a private/invitation only forum back then, and a guy named Scumbag was claiming that the sky was falling because JJ tubes were blowing up in his DR. He told everyone their only choice was to buy NOS Mazda's. (Of course, he was offering NOS Mazda tubes for sale at the time and his assertions seemed self-serving.)

I responded that in my experience modern wall voltage and his preference for excessively hot bias were the culprits, and that the JJ 6V6 were actually quite robust if you bothered to pay attention to operating parameters like Va and screen dissipation. Of course he responded that I spoke heresy because I suggested things like bucking transformer voodoo and "modding" the amp (screens resistors). In his simplistic mind any tube should be capable of being used in any amp when the schematic calls for it, without having to be bothered with such nonsense as paying attention to modern wall voltages, rational bias levels, screen dissipation, etc. Some horses just don't like water. Go figure.

Fast forward to 2017 and JJ 6V6 are now regarded as the most robust 6V6 available. But now there seems to be a problem with EL34. What's old is new. JJ EL34 are "failing" in what seem to be high dissipation applications, and some people seem to be closed-minded about changing the circuits to address the problem. Everyone seems to want the plug-and-play solution.

I have to admit that I don't understand why these "failures" are occurring, because people aren't giving us enough information to accurately identify the failure modes. If I were pressed to generate a hypothesis for the failures in the absense of good data, I'd suggest that people are experiencing screen failures and that they should design some experiments to test this idea.

A problem comes along though, when people refuse to make modifications to the circuits that help to elucidate the nature of the problem. I respect Ampagers as being above and beyond those close-minded types who refuse to modify an amp, the kind of end-users who are inclined to say that any tube should be able to be plugged into a high voltage or high dissipation application, blindly, without paying attention to the failure modes that might ensue and how to avoid them.

One of the reasons that I like this place so much is that the level of expertise is so high, relative to other sites.

I'll offer my two-cents worth of operating data in the hopes that I can contribute to solving the problem:

Watt-hours kill tubes. Drive them into an attenuator and you should expect short lifespans.

Personally, I don't use EL34 all that often, I'm more of a 6L6 kind of guy. When I do use them I prefer to use them at lower Vp than most of the prevailing amp designs. For tonal reasons I like to keep Vp down near 400-425, I protect the screens with 2K2 screen resistors, and I use reasonable bias current. I use forced-air cooling and the amp is typically run hard into a resistive attenuator, with the signal re-amped into a slave for volume. The tubes won't last forever in this setting, and I don't expect them to. The tubes do have short lifespans, but I haven't had any unexpected SIDS* with tubes that have passed burn-in. I buy from CE-D.

*Sudden Infant Death Syndrome

[Enzo]

Warranty life is inconvenient, but as a repair man, if people start bringing back repairs a year or two later claiming they never used it until yesterday and it doesn;t work. Do you fix it again for nothing? it is not so simple as the tube vendors ought to warrant tubes no matter how long you claim to have had them on a shelf. I sympathize, but it isn't simple.

WHy do CE sell as several vendors? SImple, brand loyalty. People who have been buying from one name tend to continue. You kill the name, and they wander off, maybe to another of your stores, but maybe not.

CEDist is the wholesale division, AES is the retail division. Tubesandmore is the AES web site URL. If people call your store that instead of the name, then hang out a sign with that name on it too. They make no secret of it, and anyone in the business knows the two companies are the same. I call AES "tubesandmore" all the time, but I know that is not their name, just their address. Like we hear the latest news from "1600 Pennsylvania Avenue" instead of "The White House."

[Chuck H]

Fast forward to 2017 and JJ 6V6 are now regarded as the most robust 6V6 available. But now there seems to be a problem with EL34. What's old is new. JJ EL34 are "failing" in what seem to be high dissipation applications, and some people seem to be closed-minded about changing the circuits to address the problem. Everyone seems to want the plug-and-play solution.

A problem comes along though, when people refuse to make modifications to the circuits that help to elucidate the nature of the problem.

When I do use them (in reference to el34's) I prefer to use them at lower Vp than most of the prevailing amp designs. For tonal reasons I like to keep Vp down near 400-425, I protect the screens with 2K2 screen resistors, and I use reasonable bias current. I use forced-air cooling and the amp is typically run hard into a resistive attenuator, with the signal re-amped into a slave for volume. The tubes won't last forever in this setting,...

I actually have to pick at this a little. 6v6's and 6l6's have been respected by the tube makers WRT their typical operating conditions in guitar amps and there just aren't that many posts about how the new 6*6 tubes suck. But el34's are historically important and tone specific and current production tubes typically DO NOT STAND UP TO THE RIGORS as the 6*6 tubes do. No one wants to modify their Marshall for lower plate voltages, higher value screen resistors and a cooler than tonally optimal bias to accommodate shitty tubes. Something is definitely lost in that scenario. We just want an el34 that works as per the data sheet in amps and designs (vintage or new) that are arranged for that tube model. If a manufacturer can't provide that then they shouldn't be selling the tubes as el34's!!! I'm not at all saying that we can't (or shouldn't) accommodate the new tubes that are available. We do it all the damn time. But if a Marshall can't be operated as a Marshall then a tonal legacy is lost and tube manufacturers eating the dead bones so they can shit money by selling straight up false tubes is disrespectful, lacks any trace of mindfulness and is seriously pissing me off.

[Enzo]

It is another thing from the past that just isn't as good as the originals. I doubt they will get better.

I am led to think of telephones. They used to be built like tanks, in fact the phone company owned them, you paid them a buck a month or whatever to have it. You couldn't use your own phones. When touch tone came along, they traded out your old dial phone. I think touch tone service also cost an extra buck a month. Big solid heavy touch tone phone. Then one day the supreme court or somebody decided the phone company could not monopolize the phone instruments.

Now you could buy your own phone. You could buy one at retail or from the phone company. We bought from the phone company. But they didn't let you buy the sturdy phone you already had, they collected that and sold you a much lighter phone. We could no longer buy the industrial strength phones. That's life. Soon the stores were full of cheap phones. Phones that were not as reliable, phones that sounded awful. That's life too. But aside from teh crummy units, phone service was super reliable.

Then cell phones happened. Oh so convenient, but then calls got dropped, calls might not go through, reception varied. We accepted the inferior service for the portability. And we accept the asshole talking loud two feet from our heads in line at the store. The days of one solid, reliable phone are gone. I wish modern phones worked as well, but they won't. But we still call them phones.

I wish modern tubes worked as well as the days of RCA and Sylvania, but they don't.

[bob p]

My house was built in 1957 and the guy who lived in it before I did was a phone service guy. He wired every room in the house with phone jacks and brought home phones from work. 60 years later every room in our house still has the original Western Electric made in Chicago phone in it. Built like tanks, indestructible, great tone. Since there's an extension every 10 feet in the house, and since there's not a place in the house that can't be reached by a phone cord, we've never bought a cordless unit. We successfully avoided all of the cheap crappy phones by going long on the good gear when it was still available. I guess that's the phone equivalent of having a case of NOS tubes on a shelf.

edit: forgot to mention -- my house is mostly full of *rotary phones*. I hate it when I get automated responses where they assume that I have a Touch Tone phone and can press 1 for english and 2 for espagnol, and the system is so dumb that it gets stuck in a loop when you don't press a button.

[Mick Bailey]

Here's our original house phone. Maybe 1920s and still working fine. I installed a modern patch cord and a couple of components to get it to ring properly on the modern wiring system. It's much clearer and more reliable than any new phone, plus it works in a power cut. Originally it didn't have a dial - where the dial is now there used to be a mouthpiece to speak into and there was just something to listen with instead of the handpiece. At the side was a hand crank connected to a magneto. You turned the handle and got connected to the switchboard operator who put you through. In the 40s the phone company took it back and converted it to dial.

In amp terms it's probably equivalent to a Tweed Deluxe.