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

[martin manning]

Audio tubes do indeed drive the tube/valve market.

This statement from Kittleson's Vacuum Tube Valley site, although a bit dated, would say otherwise:

"GLASS ELECTRON TUBE MANUFACTURERS
Updated 12/21/05

We currently estimate that the demand for audio tubes is growing 10% to 20% per year. Audio tubes are over a $200+ million dollar industry in the USA and possibly $500+ million dollars worldwide. The most popular tube made now is the 12AX7, followed by the 6L6GC and EL34. About 90% of all glass audio tube production goes to guitar amp manufacturers." (emphasis MPM)

http://www.vacuumtube.com/mfg.htm

[SoundPerf]

Audio tubes do indeed drive the tube/valve market.

This statement from Kittleson's Vacuum Tube Valley site, although a bit dated, would say otherwise:

"GLASS ELECTRON TUBE MANUFACTURERS
Updated 12/21/05

We currently estimate that the demand for audio tubes is growing 10% to 20% per year. Audio tubes are over a $200+ million dollar industry in the USA and possibly $500+ million dollars worldwide. The most popular tube made now is the 12AX7, followed by the 6L6GC and EL34. About 90% of all glass audio tube production goes to guitar amp manufacturers." (emphasis MPM)

Yeah, I was a wondering about this myself. I could see possibly since the audiophile people are willing to spend hundreds of $$ on tubes that the amount of tubes vs. price evens things out. But I would have guessed that based on shear numbers guitar amps exceed anything else. But in honesty I don't have clue about this. I would love to see some true statistics.

[ToneMerc]

Just ran across this

http://www.vacuumtube.com/faq1.htm

TM

[VacuumVoodoo]

I really enjoy reading all the speculative statements and conjectures, especially regarding cathode coatings being contaminated by impurities, not up to spec etc.
Guess what? Tube manufacturers (except very few kitchen table outfits) don't make cathode coating paste themselves but buy from companies specializing in chemical compounds for electronic industry.
So talk to and blame them for poor quality of cathode coating in new production tubes.
Call them. You won't have any difficulty communicating, a major supplier of cathode paste for tubes is a genuine all American company located in Danvers, MA.
Another myth to bust is the superior quality of NOS tubes. If these tubes were so good and long lasting then why were there so many TV/Radio repair shops and racks of tubes in every supermarket in those days?
Quality tubes were manufactured in those days, they were given their own designations and weren't usually sold via retail.
No manufacturer ever made any specification of tone. Neither was there a spec for TV tubes that would guarantee "brighter colors, higher contrast and greater detail in hair separation on Johns Waynes head".

[Luthierwnc]

Plus, you have to bet that a lot of the tubes that were checked and pitched were probably still pretty good. Those grocery store testers weren't designed to keep old tubes in the Philco.

Tom; let's start a sticky where people write in their experience with modern tubes. If we can, subdivided by type. We should probably leave vendor experience out. I'm mostly interested in longevity and critical failures. Tone I can (arguably) hear for myself but that's welcome too along with links to vids and audio if folks care to post those.

Whaddaya think? Skip

[Lynxtrap]

Tom; let's start a sticky where people write in their experience with modern tubes. If we can, subdivided by type. We should probably leave vendor experience out. I'm mostly interested in longevity and critical failures. Tone I can (arguably) hear for myself but that's welcome too along with links to vids and audio if folks care to post those.

Whaddaya think? Skip

To be honest, I think people like us, that's internet forums, don't make the situation better.
One guy writes in a post somewhere that Brand 'X' is bad because they failed in his amp after a week.
A hundred people reads that post and it becomes the truth for thousands.

Plus we are prone to creating myths about the "best" tube (or caps, resistors, wires and what have you) for this or that sound.
Manufacturers respond by making stuff using the old trademarks or making their products look like the old mojo components. The quality might not be anything like the old stuff (if the old stuff was really as good as we tend to believe).
That's happening with guitar and all sorts of gear, and amp components are no different.

So a sticky with experiences and opinions... I think just reading through this thread shows why that won't work very well.

[SoundPerf]

Just ran across this

http://www.vacuumtube.com/faq1.htm

TM

There was some nice information in there. So it seems that poor vacuum is more likely a bigger factor than cathode coatings, etc. Which kind of falls in line with a lot of failure reports I tend to read. Also vacuum "hardness" would be the best way to guage lifespan and predict return purchases. If anything like that actually exists.

Like in the article and with everything, competition is ultimately what promotes quality with a reasonable price point. So "In the name of tubey goodness!!" this swing to centralized control in industry, goverment and everything must be put to a stop.

[Alexo]

Given the tendency of cultural and intellectual evolution by generation, 20 years from now, kids will be rolling their own tubes and discussing quality control of metallurgical compounds, and whether imported tungsten sounds as good as domestic.

[markr14850]

I wonder how much of a tube could be built by a modern 3D printer.

[cbass]

Another myth to bust is the superior quality of NOS tubes. If these tubes were so good and long lasting then why were there so many TV/Radio repair shops and racks of tubes in every supermarket in those days?

There is no doubt in my mind that NOS tubes are more rugged than new manufacture.

The reason there was so many reapir shops and replacements available is becuase back then every single household had tube electronics.Millions upon millions of tubes were being made.Sure there were some bad tubes here and there and they do eventualy wear out but overall old tubes were much more rugged.They had to be to live in military equipment and electronics that people depended on everyday.

Just one example.(doesn't really prove anything) I dropped an old 7591a about 3 feet on to a ceramic floor.I think my heart stopped for a few seconds.Bounced three times and I'm still using it daily. That was about 3or 4 years ago.
I can't imagine a jj or EH living through that.If the thin glass didn't break.It most likely would have knocked something loose internally.

[M Fowler]

To be honest, I think people like us, that's internet forums, don't make the situation better.
One guy writes in a post somewhere that Brand 'X' is bad because they failed in his amp after a week.
A hundred people reads that post and it becomes the truth for thousands.

I don't listen to any of you guys

[VacuumVoodoo]

I don't listen to any of you guys

I don't even listen to myself anymore...even though I have a pair of these:
[img:300:400]http://tubewonder.com/images/various/fa ... s_0407.jpg[/img]

[XgamerGt03]

Just one example.(doesn't really prove anything) I dropped an old 7591a about 3 feet on to a ceramic floor.I think my heart stopped for a few seconds.Bounced three times and I'm still using it daily. That was about 3or 4 years ago.
I can't imagine a jj or EH living through that.If the thin glass didn't break.It most likely would have knocked something loose internally.

As a counter example, I've dropped a NOS and new 6V6 tube onto hard floors as well. The NOS tube (GE I believe) shattered on impact instantly, the new tube (a JJ tube) survived the fall and is still working perfectly.

The two drops were both from the same desk so I'm going to assume that impact would be the same.

[Luthierwnc]

Extending this thread beyond its useful life (although I am glad to know more about the market), I haven't seen much in any of the places I visit about what alterations modern amp makers make for eastern tube shortcomings. In most cases, we wire them exactly like the original schematic, slap in a pair of golden mongoose tubes and wonder why it just doesn't sound like Dad's amp -- or shines brightly for a few seconds. Bigger screen resistors? Bigger grid stoppers? Flyback diodes on the plates? Fused cathode to ground connections? Gotta work with what you have.

To be honest, I've been happy with at least 90% of the newly manufactured products in the market and, in the main, they keep getting better without my input. sh