[ThurstonX]

  You can see the code at the top. The year appears to be L = 1962.

 
That seems to be the least understood form of dating code.  !950 is the start year, correct?  L = 12(th letter), so, 1962.  And the other two numbers are the week of that year, IIRC.

 

[Oskari]

That's my recollection as well.

 

[Astral Abyss]

   
That seems to be the least understood form of dating code.  !950 is the start year, correct?  L = 12(th letter), so, 1962.  And the other two numbers are the week of that year, IIRC.

 
Yup.  It should match your etched codes.

 

[kolkoo]

With a few hours of burn in on the '66 and '71 Mullard/Heerlen pair I can say you can certainly hear a bit of difference between the two channels at certain songs. So I guess matching IS really important Unfortunately I have no way to measure these tubes to see the difference in Ia or Gm but I'm also guessing the tube construction/factory will play a role as different frequencies will be present in different ways. Going to keep these and maybe find pairs for them at a later time or resell them 1 by 1. Meanwhile I'll keep burning in my Dario Miniwatt E188CC '62 Heerlens - they sound great and I'm waiting on some 7L8 '62 Heerlen Valvo E88CCs (matched this time) to check them out as well.
 
EDIT: After switching back to the '62 Miniwatts I can really say listening to an unmatched/mystery pair like that really puts things in perspective. The Miniwatts compared to that pair are a whole different ball game.

 

[ForceofWill]

With a few hours of burn in on the '66 and '71 Mullard/Heerlen pair I can say you can certainly hear a bit of difference between the two channels at certain songs. So I guess matching IS really important Unfortunately I have no way to measure these tubes to see the difference in Ia or Gm but I'm also guessing the tube construction/factory will play a role as different frequencies will be present in different ways. Going to keep these and maybe find pairs for them at a later time or resell them 1 by 1. Meanwhile I'll keep burning in my Dario Miniwatt E188CC '62 Heerlens - they sound great and I'm waiting on some 7L8 '62 Heerlen Valvo E88CCs (matched this time) to check them out as well.

EDIT: After switching back to the '62 Miniwatts I can really say listening to an unmatched/mystery pair like that really puts things in perspective. The Miniwatts compared to that pair are a whole different ball game.

Was the difference just in volume from the output difference or tonal qualities as well since they're different tubes?

 

[kolkoo]

Was the difference just in volume from the output difference or tonal qualities as well since they're different tubes?

I feel like there was a volume difference within specific tones - I lack to vocabulary to describe which ones. Also some music in general did not sound nearly as good with that pair.

 

[ThurstonX]

  With a few hours of burn in on the '66 and '71 Mullard/Heerlen pair I can say you can certainly hear a bit of difference between the two channels at certain songs. So I guess matching IS really important Unfortunately I have no way to measure these tubes to see the difference in Ia or Gm but I'm also guessing the tube construction/factory will play a role as different frequencies will be present in different ways. Going to keep these and maybe find pairs for them at a later time or resell them 1 by 1. Meanwhile I'll keep burning in my Dario Miniwatt E188CC '62 Heerlens - they sound great and I'm waiting on some 7L8 '62 Heerlen Valvo E88CCs (matched this time) to check them out as well.
 
EDIT: After switching back to the '62 Miniwatts I can really say listening to an unmatched/mystery pair like that really puts things in perspective. The Miniwatts compared to that pair are a whole different ball game.

 
Thanks for taking one for the team and sharing the results.  I imagine you can find mates for them, though without measurements, it remains something of a crap shoot.

 

[ForceofWill]

I wonder if you could send them off to one of the reputable tube vendors to test and maybe sell you a match.

 

[kolkoo]

I actually am trying to find a tube tester on the cheap somehow (even before this pair). But it feels like buying a used tester is even more challenging than buying tubes. But who knows maybe I'll be lucky and find a deal somewhere in my country.

 

[oAmadeuso]

  I actually am trying to find a tube tester on the cheap somehow (even before this pair). But it feels like buying a used tester is even more challenging than buying tubes. But who knows maybe I'll be lucky and find a deal somewhere in my country.

I've seen people on eBay offering a tube testing service I think.

 

[kolkoo]

http://www.ebay.com/itm/151883081685
 
This looks like a Pinched Waist D-Getter 1958 Heerlen tube. I'm not sure about those measurements but maybe it's worth the bid!

 

[billerb1]

You don't see many pinched waists with the old Miniwatt logo...and this one was a beauty.  AND from Eindhoven !!  7L1 and tested great.
Just went for $355.  I thought it would be more like $400-$450.
 
http://www.ebay.com/itm/E88CC-pinched-waist-D-getter-from-philips-miniwatt-test-100-7L1-code-/301797037328?_trksid=p2047675.l2557&nma=true&si=mp%252BOGEWQogIJDcZvqXhNtH%252BCk04%253D&orig_cvip=true&rt=nc
 
(scroll to bottom)

 

[Hardwired]

  I actually am trying to find a tube tester on the cheap somehow (even before this pair). But it feels like buying a used tester is even more challenging than buying tubes. But who knows maybe I'll be lucky and find a deal somewhere in my country.

 

  I've seen people on eBay offering a tube testing service I think.

 
I ordered this kit: http://www.dos4ever.com/uTracer3/uTracer3_pag0.html
 
Just got it soldered together and tested, and am wiring up a 9-pin socket to it, but trying to find guidance for how to attach and test the 9822 tubes is not going quickly. If someone here has more knowledge or has used this kit, feel free to enlighten me.  Anyway, it's an alternative that should work better than vintage, overpriced tube testers that don't work that well with 9822 tubes anyway because of the low voltages involved, as I understand it.

 

[kolkoo]

   
 
I ordered this kit: http://www.dos4ever.com/uTracer3/uTracer3_pag0.html
 
Just got it soldered together and tested, and am wiring up a 9-pin socket to it, but trying to find guidance for how to attach and test the 9822 tubes is not going quickly. If someone here has more knowledge or has used this kit, feel free to enlighten me.  Anyway, it's an alternative that should work better than vintage, overpriced tube testers that don't work that well with 9822 tubes anyway because of the low voltages involved, as I understand it.

I've actually been eyeballing that for a while now. How complex is the assembly? I have a soldering station and know my way around soldering but for simple things like cables mostly. That's what's stopping me as having a curve tracer to do even more complex matching is very appealing to me.

 

[Hardwired]

The circuit board is well laid out and the kit parts come in multiple bags to keep stuff together. The instructions are pretty good if you know what you're doing (I hadn't used a soldering iron in 25 years, so I had some problems) and are laid out to do a section of the circuit and then test it, and so on. There are some solder spots that get kind of close to each other (and soldering inductors absolutely sucks, just FYI) but if I managed to produce a working kit you should be able to as well.
 
I ended up buying a decent soldering station and a bench power supply, plus a solder sucker for when you screw something up (and I used it a lot at first). Once I got through the first couple of sections and worked out how to reliably solder the inductors onto the PCB and how to make good solder connections, it took about 2 weeks total to get it assembled, just working on it when I felt like it. I still haven't figured out a case for it but I'll wait until I figure out how to test a 9822 tube first.
 
The software that the kit creator, Ronald, provides is pretty complex and will do some pretty sweet stuff. There is alternative software someone else wrote that may be simpler and has config files for various tube types built in which is nice, but I need the wiring instructions for the socket-to-board connections. Evidently dual-triode tubes can have both tube sections tested at the same time but you have to know how to make the connections.
 
And I may just be dumb and you'll have it working in no time but I like to do extensive research before entrusting my tube babies to some strange hardware.