God help me, I've become a NOS tube snob.

[suncrush]

I never thought I'd be that guy, but I found a HUGE box of old tubes at work.  Most of them were for televisions, but there were a couple dozen common preamp tubes in there.  Mostly GE and Sylvania, but a few Telefunken pentodes, too.

The difference is real, man.  They sound so much better than the new-built stuff, even including the big "name brands" that are still in production.

A while back, I think someone posted a link here about how QC was better for run-of-the-mill tubes in the 60s and 70s than even high-end tubes now, and man, if that's it, it shows.

[vigilante397]

I have a friend that makes a hobby out of hitting up thrift stores for old appliances (especially TVs and oscilloscopes) and pulling out the tubes. When he met me he realized I would probably get more use out of them since none were standard 12A*7 type stuff so he gave me a box of 170 tubes. I never really paid much attention to them until a couple weeks ago when I finally bought myself a tube tester, then I've started to go through the box.

I'm only about halfway through, but out of the 80 or so vintage and NOS tubes I have tested there have been 4 so far that tested bad. In contrast I also work as an amp tech during the day and I keep all the tubes I pull out of amplifiers that go through work, so I tested all of those as well. They were all made within the last 10 years or so, random sampling of Chinese (Sino I think?), JJ, and Sovtek. So compared to 76/80 of the vintage were good, only 17/30 of the newer ones tested good, and even then most of my vintage ones tested between 75 and 90%, whereas I don't think any of the newer ones tested above 80%.

Long story short: the difference is definitely real.

[amptramp]

It's not snobbery, it's reality.  I have a number of antique radios and I usually see about 4% bad tubes in them and these tubes have been in use and usually date back to the 1930's and 1940's.  This is a case of technology disappearing because all the skilled practitioners have retired or died.

[PRR]

> all the skilled practitioners have retired or died.

To be blunt: all the older low-paid women got laid-off in the 1970s. While skilled scientists play a part, consistent high quality is about worker experience.

[suncrush]

> all the skilled practitioners have retired or died.

To be blunt: all the older low-paid women got laid-off in the 1970s. While skilled scientists play a part, consistent high quality is about worker experience.

And materials, and machining, and quality inspections.  The modern plants in China, Russia and Slovakia are making millions of tubes each year, so the workers have plenty of experience.  But the materials they're working with are poor.

[Hatredman]

But the materials they're working with are poor.

Also, old legislation were less demanding on environment-friendly manufactoring processes and raw materials, so old tubes may have radioactive or poisonous adictives that newest ones are not allowed to have.

Also, programmed obsolescence. Why sell a tube with a 60-year life span if you could sell a 5-year and guitarists will happily buy them?

[thermionix]

INB4 "What is better?" 

I'm with ya OP.  Amperex Bugle Boys are usually my favorites.  What Telefunken pentodes did you find?  Any EF86s?  If so, build an amp around one.

[suncrush]

INB4 "What is better?" 

I'm with ya OP.  Amperex Bugle Boys are usually my favorites.  What Telefunken pentodes did you find?  Any EF86s?  If so, build an amp around one.

EF83's.

Now I need a good NOS 12AX7 for my Micro Terror.

[amptramp]

I joined the London Vintage Radio Club even though it is over a hundred miles away in London, Ontario, Canada and the bargains I have found on old stuff is phenomenal.  Large boxes of tubes may go for $10 and usually have some of the popular audiophile / guitarist tubes in them.  Old instruments go for very low prices - I have a classic Eico 960B resistance/capacitance bridge that I got for $10.  I have signal generators that go for an average of $5 depending on what type it is.  Meters usually go for $5.  I have seen radios go for $1 to $1375 (for a Mercury Ten).

Once you learn to design with tubes, you realize how forgiving they are.  The components around them do not need to be accurate values in order to get a circuit to work, although things like filters may call for precision values.  They run on pretty much any voltage within their limits but do not die immediately if they are subjected to overvoltage.  There is no ESD problem.  Input impedance remains high and interelectrode capacitances are low and stable.  If it vaguely looks and smells like the right circuit, it will work.