[OctavianH]

By the way the Valve Museum this guy, Patric Sokoll, put on this website is exceptional value. If on the previous link you can see a lot of EL34 photos to identify different types, he has a lot of info. He has also a page for EF6! So my priorities when going next time in Munchen drastically changed. From Andechs beer pub to ask this guy for a beer. I bet he would be intersted in my plans for the Old European Pentode Tribute amplifier, a subject where my girlfriend does not seem to want to discuss too much. LOL

Here EBC3 with video! But he misses a lot of types. I can help.

 

[OctavianH]

Watching mr. Sokoll measuring on Funke W19 the EBC3 I realize how much better is my simple modern tube tester.



This is the one I have and the guy in France was very helpful. Recommended if you want a simple tube tester. Of course, a more advanced one can be this one.

What I can test on this one very easy is emission, current at a specified operating point and this is all I need to determine what settings of my manual grid bias I need to make to put any tube on the amplifier. Well any = which suits the circuitry (6.3v heaters, can be biases, longer story). Transconductance is not measured directly but can be determined via several measurements. For me it is enough, but I strongly consider to go towards a curve tracer.

 

[ARCXENOS]

Watching mr. Sokoll measuring on Funke W19 the EBC3 I realize how much better is my simple modern tube tester.



This is the one I have and the guy in France was very helpful. Recommended if you want a simple tube tester. And this is the website where I am unsure why they do not have a fully built tube tester but for sure you can ask.

How is that duovac supposed to test the 4pin DHTs, a customized adapter?

 

[OctavianH]

How is that duovac supposed to test the 4pin DHTs, a customized adapter?

I never tested a DHT on it, but since I have only octal sockets on my amplifier I also have adapters towards octal for more "exotic" tube sockets. If I want to test for example 807 I wire the tester for 6V6 and put the tube on the adapter. I always measure or determine grid bias for my 200V/20mA operating point, I do not really care if the tube measures something else at other values. This is why I do not necessarilly trust Ebay sellers measuremets, each amplifier is different and they measure like mr. Sokoll, to some "standard" values from those manuals of their tester, it will not necessarilly match what you will find.

PS. That simple tube tester has only octal and noval sockets. But you can measure directly via adapter like on your amplifier. You put the tube with socket X inside the adapter towards what you can use on your amplifier (which has to be octal or noval, my case 6V6 pinout) and then measure something directly triode strapped (in my case). Not the best way for health or other measurements but for what I need it's ok. Octal and noval socket tubes can be measured directly on the amplifier.

 

[OctavianH]

Time for me to go towards something I already consider classic: 4654/EL50 and EBC3. SFR P17C has not convinced me, the "killer" of the 4654 which is not a sibling, a derived PE06/40P french version is not better for me. Of course, debates can exist and I understand why some prefer that one. In my view it's only a more powerful sounding RT EL39 style of tube, a french made PE06/40P.

I think in the future I will return to EBL21 because I never spent enough time with it. EBL21 on input, maybe try some EBL1 on output (I never done than, has to sound in the same way as EL3N). There are a few things I can do with the tubes I already have and which might bring some news.