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Monday, May 29, 2023

Tube of the Month : The EL3N

Hi!

This months tube is an old European output pentode. Meet the EL3N.


 

This tube was introduced by Philips in 1938 and meant to be used as Class A or Class AB output tube.


The EL3N is indirectly heated and has a side contact base with 8 contacts of which 2 remain unused. The pinout is shown on the left. The heater operates at 6.3V and needs 0.9A of current. A tube which is rarely seen in use nowadays. The Philips data sheet does not give a lot of information besides Class A and Class AB operating characteristics with a measly 8W stated as output power from the latter. I never used this tube myself and the few samples I can show were leant to me. Since the data sheet does not give any plate curves, I took the triode curves with a tracer:




Here are two samples from Philips, branded 'Miniwatt':




The EL3N had the characteristic red band above the base and smoked glass from the 'red series'.









The side contact base:






The only other sample I can show was made by Tungsram:





The box:







A few close up shots:





Since there is no getter applied at the top dome this tube gives a better view to the internals and the grids are nicely visible:







Not too much glow visible from the heater:




That's all for the EL3N. Stay tuned for more tube presentations in upcoming posts.

Best regards

Thomas



4 comments:

  1. Thomas great timing. I have pair of these in front of me and am trying to figure out if they’re gonna be good as a driver tube transformer coupled to output section 300b’s in push-pull. I have the setup running well with 7n7’s ala the old sun audio schematic, but want totry a few options before I hard wire it all. Any suggestions?

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    1. Hi! I never used these myself. So since you already have a set up running you are in a better position to suggest how to use them than me ;-) Simply try and check what works for you

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    2. I’ll let you know. I want to follow up by touching base on another tube. I built a preamp following from your filament bias O1A. It was an lighter lift because I built it around the 31 - filament bias. I haven’t used either the 801 or O1A preamps I have much since completing this, it’s a great preamp. I may also try the 31 to drive the push pull 300b’s it has such fantastic tone and I am not too concerned with power 10 watts will be okay and I am limited to 10 ma into the interstage. And with an attenuator at the input has a simple immediate sound. It’s amidst all this that I found the EL3N’s in my closet and thought they might finally deserve a chance.

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  2. Hi, i came across this yt-video made by Mishuzma with images and sound of a EL3n single ended in working order. I have no connection to anything from this site but thought it's worthwhile to see this rare Philips tube in action. Enjoy Dutch pride;-)
    https://www.youtube.com/watch?v=JoMtYuqAbjA

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