[Golfnutz]

I did not tried one at a time. Sorry.

Right, but those results are just above minimum acceptable values (21-50 mA and >4000 Gm).
 
Not sure I would purchase anything with values  less than 30.00 mA and less than 6000 Gm. Based on the NOS tubes I have and the test results with the same tester.
 
At least they are matched fairly well, but I would still do another series of tests one tube at a time to see if the numbers are better.
 
Edit: Try testing some other EL34 tubes to get an idea of how they measure. Maybe your results are normal to be this low (again, with this tester, I would do them one at a time - you don't get true 400v with all 4 tubes in at the same time). Part of the reason to purchase a tube tester is to see if you're getting healthy tubes from a seller.

 

[TheAttorney]

  Right, but those results are just above minimum acceptable values (21-50 mA and >4000 Gm).

Very much so, but these tubes do at least look as if they are the claimed true NOS, And the fact that they are reasonably well matched makes me wonder if there is something about the way this tester drives the tubes that makes it different to the big testers?
 
As you said, try one at a time and also measure the other tube sets available. 

 

[Golfnutz]

  Very much so, but these tubes do at least look as if they are the claimed true NOS, And the fact that they are reasonably well matched makes me wonder if there is something about the way this tester drives the tubes that makes it different to the big testers?
 
As you said, try one at a time and also measure the other tube sets available. 

A friend of mine has the same tester and he showed me how the voltage sags when testing 1 tube, 2 tubes, and 3 tubes at the same time (4th tube slot was used for multi-meter).
 
I'm sure these tubes are fine, not trying to imply that they're not. They just seem to measure a bit low compared to what I've seen with this tester (95% of my approx. 30 NOS tubes measure >30 mA and >6000 Gm with this tester - nothing as low as his results).

 

[bmichels]

Well you are right, there is a difference between testing 1 tube at a time and 4 tubes together:
 
When testing all 4 tubes together I got as you remember :  CD = 24,4  -  24,3  -  25,4  - 24,8        Gm = 4,86 - 4,66 - 4,90 - 4,72
 
 
So I took tube N°1 who was at CD = 24,4  &  Gm = 4,86 and... I tested it alone and I got :   CD = 26,3  and  Gm = 5,03  !    
 
this is +2 mA, and close to the value of 27 mA that the seller mesured with his professional equipment before shipping to me.
 
So... I guess that the real value for the 4 tubes are more likely to be the one mesured by the vendor :  27,  27,  29 & 28     

 

[TheAttorney]

Well... they are matched and your results are close enough to the seller's claims, but....
 
These results still look far too low to me. Here is a measurement of a used metal base tube on sale today at tubeworldexpress:
 
1 tube) EL34 Philips Miniwatt Holland metal base (SY1-56K=1956) - strong single - Cost $400
102ma Gm=12,800
 
Now that's what I'd call a good result - and it's not even NOS. Probably higher that one would normally expect even for a NOS tube, but it gives an indication of what's possible.
 
Although your seller (tube depot I guess?) hasn't actually said anything strictly untrue in their advertising (apart maybe from the bit saying they are "just as they left the factory"), to me the implication of a $600 NOS tube is that it should be at least somewhere close to top measurements.
 
So personally, I'd go back to your seller and ask them to explain or justify these results.
 
Don't panic at this stage, as there could still be other variables that we are not aware of, so it's possibe we're not comparing apples with apples.

 

[Ali-Pacha]

Hey,
 
asking the question again, here and there (BHSE thread). Has anyone ever tested STR-450 Mesa Boogie / Siemens NOS RFT (exactly the same) ? Thanks !

Ali

 

[Crashem]

I am really curious about the same, but also about the original Telefunken EL34 including the metal Telefunken.

 

[bmichels]

  Hey,
 
asking the question again, here and there (BHSE thread). Has anyone ever tested STR-450 Mesa Boogie / Siemens NOS RFT (exactly the same) ? Thanks !

Ali

 
are you speaking about those ? 
 

 

[bmichels]

I thought that there was only one type of Philips Metal Base, but now I also see other Philips holland called "EL34 Metal Base Extended Base".  
 
--> What is the difference with the "standard" 1955 (short) metal base ?  Are they supposed to be as good as those "standard base" Philips metal base ?
 

 

 

[georgep]

The extended base are the very first iteration of the el34 tube.

 

[georgep]

Hey,

asking the question again, here and there (BHSE thread). Has anyone ever tested STR-450 Mesa Boogie / Siemens NOS RFT (exactly the same) ? Thanks !


Ali

These were discussed at least once already in the thread. Conclusion was not as good as the dutch/belgian/British NOS stuff, but certainly better than the current production stuff.

 

[Crashem]

I am aware of 4 kinds of "Metal" EL34. 
 
1) Philips EL34: Been talked to death. Link below is good resource.  I believe the "long base" are the 1954 ones.
1954
http://www.tube-classics.de/TC/Tubes/Valvo%20EL34/EL34.htm
 
2) Mullard EL34: I believe these are nothing more than rebranded Philips metal EL34
 
3) German EL34: There are some metal EL34 made in Hamburg. Siemens branded.  Never have seen any for sale
 
4) Telefunken EL34: These I am most curious about.  The structure almost seems Mullard XF1-2 like.  With OO getters.  Sometimes the getters are flat and sometimes at angle.

 

[bmichels]

  I am aware of 4 kinds of "Metal" EL34. 
 
1) Philips EL34: Been talked to death. Link below is good resource.  I believe the "long base" are the 1954 ones.
1954
http://www.tube-classics.de/TC/Tubes/Valvo%20EL34/EL34.htm
 
2) Mullard EL34: I believe these are nothing more than rebranded Philips metal EL34
 
3) German EL34: There are some metal EL34 made in Hamburg. Siemens branded.  Never have seen any for sale
 
4) Telefunken EL34: These I am most curious about.  The structure almost seems Mullard XF1-2 like.  With OO getters.  Sometimes the getters are flat and sometimes at angle.

 
thanks a lot for those detailed explanation about metal base EL34

 

[Crashem]

Found a couple of telefunken EL34 on ebay.  Grabbed the photos.

 

 

[bmichels]

Found a couple of telefunken EL34 on ebay.  Grabbed the photos.

Did you buy them ?