Tubes - Who Wants to Talk About Quality Control???

[MikeSafreed]

Does anyone want to discuss current-production tubes and what's going on with the apparent lack of quality control? The inability to get a sufficient quantity of tubes that actually work (with decent measurement numbers) is making me consider giving up my amp building business. I would love to hear from other builders about their current experiences - who is selling tubes that have actually been tested and work, who is selling junk, etc... Personally, I'd love to trash a few tube companies and resellers and let the world know that they sell junk.

Anyone else want to talk about this? If you have something positive to say about a tube manufacturer or reseller, let's hear from you, as well. If I am overlooking a manufacturer or reseller that delivers tubes that are worth buying, I'd seriously like to know who they are...

I'm not sure there is anything that can be done to get tube manufacturing back on track, but if something isn't done, tube amp building isn't long for this world (in case you haven't noticed, the supply of quality NOS tubes is almost gone)...

[CHIP]

May I add, Why can't a tube manufacturer produce tubes with NOS quality and sound?
In this high tech day and age we have mobile phones that understand human commands, Yet we can't reproduce a vacuum tube that matches 1950's technology.

[VacuumVoodoo]

Tubes out of former Soviet block countries have very uneven quality. It depends on which day of the week they are manufactured. Avoid anything made on a Monday, Thursday and Friday. On Monday they are hang over from weekends drinking, Thursday they already think of weekends drinking and on Friday they are already mentally on Saturday.

On the technical side: the old alchemists are gone so the cathode coating (the paste covering the cathode is what emits electrons, metal pipe is only a support) is not as efficient as in the old days, it is also not as carefully prepared so it's quality (= electron emission) varies. This leads to various tube grading systems so they can sell tubes that by old specs should be destroyed. If they did this, production yield would drop and prices would have to go up. Probably close to NOS levels.
Example verifying this is JJ releasing replica of 6386 tube, a twin remote cut off triode. For use in its main application (vari-mu compressors) the triodes must match and track well over their operating range. This requires very careful winding of the control grids (winding pitch varies over grid length) and tight geometrical tolerances of the whole structure. It's not a mass volume product.
It retails at 120$. Let's say they tighten their QC across the line and begin offering high quality ECC83 at 60$. Would you buy?

[ToneMerc]

I'm not sure there is anything that can be done to get tube manufacturing back on track, but if something isn't done, tube amp building isn't long for this world (in case you haven't noticed, the supply of quality NOS tubes is almost gone)...

Here's the hard fact, your business is based around a consumable that is obsolete.

From an investment business standpoint what's going to turn it around or why should it be? Look at it this way, vacuum tubes are a terribly obsolete technology and I don't see venture capitalists standing in line to invest in 100 year old electronic technology, much less a materials/intensive consumable that's used by a very,very small segment of the world population. Mike if you had 2 million to invest and you were looking for ROI, I bet it wouldn't be in the niche' vacuum tube business.

When the military superpowers of the world decided to leave behind vaccum tubes, the writing was on the wall. Also, one would be nieve to believe that some of these high voltage capacitors will still be found widespread in the near future as well.

The market bears what the majority of todays customers demand; a cheap tube that works, nothing more, nothing less. The majority of these consumers aren't willing to pay for a new NOS tubes. These are the same folks that complain that $100 is too much for a quad of today's cheap tubes.

TM

[ToneMerc]

On the technical side: the old alchemists are gone so the cathode coating (the paste covering the cathode is what emits electrons, metal pipe is only a support) is not as efficient as in the old days, it is also not as carefully prepared so it's quality (= electron emission) varies. This leads to various tube grading systems so they can sell tubes that by old specs should be destroyed. If they did this, production yield would drop and prices would have to go up. Probably close to NOS levels.

Ditto

TM

[Cantplay]

As a builder, you can choose tubes that are not commonly used.

I have a couple of amps that use 6JN6 sweep tubes as power tubes. Cheap and plentiful.

Lots of other tubes available that just have different base or pinout(7N7 vs 6SN7) or different heater voltage.

Can we still make good tubes here? Yes. Western Electric is making good 300B, at crazy prices, and selling out all production. But even they have said that when their raw material supply is one there will be no more.

John

[brentm]

Isn't the variances in QA/QC just the nature of the beast? I don't have any test equipment, but I seem to have to take a handful of "NOS" RCA tubes to find one that I like in a certain position. I wish I did have a tester so I could back up my assumption with some hard facts. But even tubes of yesteryear seem to have the same issues that current production tubes have today.

That said, I'm not sure what sound or type of amplifier you're building. But most current production tubes just don't have the sound I like. And I've tried them... I have two boxes full of tubes that I've rolled in and out... with everything but telefunken's in it (just can't stomach the dough to potentially be unhappy with this tube).

I remember fixing up a buddys newer Fender amp. The IC caps were leaking, so I swapped out all the electrolytics and retubed it. I took a couple of "NOS" tubes from my stash and thought they sounded great but he called me complaining of weird ghosting sounds. Turns out the tube had some mechanical noise coming from it on certain notes (microphonic I guess?). I swapped them all out with new replacement Groove Tubes and he has been happy ever since.

But I guess my only advice to you is when you find something that works, stock up on it. And I'm sure any "stock" would have a pile of rejects unfortunately.....

[brentm]

(in case you haven't noticed, the supply of quality NOS tubes is almost gone)...

Another interesting thought.... There is definitely a finite supply of them, but how big is the supply???? I mean guys base their businesses on them, and I can't help but think that these guys are able to track down the mid-west barns with their rafters full of boxes of tubes with stories of grandpa's TV repair service. Kinda sounds like a pickers episode...

[martin manning]

As always, vote with your $, and reject product that fails to perform. This could mean buying only tested devices or insisting on the option of returning sub-standard parts. Re the 300B, that's a niche within a niche, no? In general there is reason to believe that niche products can survive, and there are many examples today, but a premium will always be required for viability

[sharkboy]

I buy from Tube Depot and Antique Electronic Supply regularly. I also pay the extra bit to get them pre-tested and screened at TD. I have been happy with both.

My experience is mostly with initial quality, since I don't get much time to play and haven't had an electric gig in years. I do think that most modern tubes don't allow the same amount of torture the old ones did.

My favorite sounding modern brand, EI, had poor QC, but did make some incredible tubes. Their 12ax7 long plate and EL84 sounded as good to me as any tubes ever made.

I think that NS is getting better with QC than they used to be (their first forays into the Mullard brand caused me a fair amount of consternation.) I haven't yet gotten a NS Tung-Sol I didn't like.

I have had good luck with the robustness of JJs, but not always the sound.
My favorite tubes were the "made in US" GT6CA7-GE, but I broke one of the pair and they had ended production. I tried the GT6L6-GEs recently and quite like them.

I have one pair of SED tubes and I'm happy so far.

-Markg

[Milkmansound]

I have had good results with Ruby branded tubes. You have to pay extra for them to test them, but they offer a 6 month warranty which is awesome. I have had a few tubes go south and all you gotta do is send them back for replacement.

Using NOS tubes is out of the question for my new builds, because the prices are insane. My prices are already insanely high, so adding another $700 or so is not very appealing.

Other than that, I find the new production tubes to be horrible. JJ output tubes are unusable in a combo amp. The Tung Sol stuff is terrible. Winged C preamp tubes are noisy...

I had to go through a LOT of new tubes in order to find ones that I liked and that would produce a stable amp. Many tubes got thrown away at my expense, but its worth it now that I have everything dialed in I can confidently sell amps and know that the new tubes in them can be trusted.

[briane]

May I add, Why can't a tube manufacturer produce tubes with NOS quality and sound?

blame the laws that keep people from breathing boron gas. Tell, do you just want some poor asian doing for you? no, they outlawed that too.

You and your buddy's did apply for that highly toxic job breathing boron gas, right?

playing with mercury is fun too. not.

making good tubes is very toxic.

I like JJ and EH. still runs about 50%. What do you think fender does? They have a deal to send them back if they suck, and thats why small cant compete when the materials going in are shoddy. If your a business, you HAVE to get the same deal as they do to compete. Exactly why I wont do transistor work anymore, there I run about 19 out of 20 as shoddy.

[jestaudio]

I have a good supplier(on ebay) i get NOS ei tubes from, he grades them before sale, i have never had a microphonic tube off him and the EI,s sound great, that being said i have also had some nice EH,s as well for my mesa, sounded far better than the crap mesa try and sell these days

[Gaz]

I dunno, the only bad luck I've had (however many times over) was with new tubes is the JJ KT77, and now I just don't buy them anymore. I get a bad preamp tube now and again, but I don't think I'd stop making amps because of it.

Tubes are replaceable parts, and most of your customers, I assume, probably weren't around when tubes were actually well made, so I don't think they'll know the difference when they have to change them out more often than they would've in the 60's. Most companies don't offer a warranty on tubes for a good reason, and as a company of your own, I'd follow suit.

I personally have no reason to complain - tubes are still cheap, sound good enough, and are cool and fun. Do I think the OP is over-reacting? Not necessarily, but changing his outlook may be the only way to solve this problem.

[XgamerGt03]

A lot of raw materials for just about any electronic device come out of China, especially rare earth metals and the like. I don't know the exact make up of all of the parts in a tube but I'm guessing that they do use some rare earth metals.

China is no longer exporting as many of those metals, and they are being extremely selective about who they export these metals to, so it stands to reason that many manufacturers are starting to have to make it with what they have. I've personally noticed a drop in the quality of a lot of tubes that were not made in China. I've never been big on Chinese tubes, but I might start trying a few of them with this knowledge in mind.

As far as modern production tubes being the same as NOS tubes... I think we've outlawed far too many chemicals that were likely used in production then to get the same results.