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Thursday, February 23, 2017

News from the ELROG Tube Factory 4


While production of the 300B, 211 and 845 tubes is in full swing, the next ELROG tube type is in development.

The first prototypes are being made. The tube will be launched at the High End fair in Munich this May. Here another teaser photo:

More abut this new ELROG tube in upcoming posts.

In a previous post I showed some photos and video clips of the assembly of the filaments of a ER300B. Today I will show the next steps in the process of vacuum tube making.

Here we see the electrode system of a 300B with filaments and grid. Only the plate is still missing. Each assembly goes through careful inspection and alignment.

Proper alignment of the grid ensures that the finished tube will meet the specifications and pass final tests.

Here we see Olena carefully inspecting and adjusting this vital part of an ELROG 300B:

Next the glass base is prepared...

... and the electrode system is welded to the metal rods in the glass base:

Now the system gets washed in a special solution before the plates are mounted.

Here we see Matthias inspecting one piece of the plate which is made of two halves.

Adding the plates to the system...

... welding the plates to the support rods which run at either side of the tube:

This is the result from this step:

Now the two halves are welded together so that there is no gap remaining between them:

The only part missing before the internal construction is complete is the getter. The getter is stored in a little ring:

This ring is mounted at the top of the system. Here it holds the getter material which gets flashed and creates the silver mirror surface later in the production process.

Now the internal structure is ready to be sealed within the glass envelope.

This step will be shown in an upcoming post. Stay tuned!

Best regards



  1. I am guessing an 841. The world needs a new high mu DHT.

  2. These are great videos showing the attention to detail and craftsmanship that goes into each tube.

  3. 46, I hope! Or if it must be something else, I would be fine with VT-63... :-)

  4. Replies
    1. Ok, if the cross sum of the original tube is 13 the I know what is is ;-)