Redesigning The WE 101D

After building a lot of triodes of various designs I've settled on using the planar element path. There certainly are a good selection of designs to borrow from going back to the 20's and 30's. I decided that I really like the look of the WE 101D and it's still a popular tube if eBay is any indication. There are some aspects of the original design that can be simplified and the glass arbor can be dispensed with by using the extra pins on the button pinch to increase the rigidity of the elements. I've also chosen to use parallel filaments instead of the 'V' or 'M' shaped ones. The tennis ball envelopes are cool looking, too, but I'm going to use a plain vanilla cylindrical approach to start with because the tubes will fit into the bakeout oven that I'm using now. I'm playing with making the tennis ball bulbs using the new glass lathe and somewhere down the line I'll make a new oven to handle them.

The photos are of an early version of a planar design that was welded up by just eyeballing the alignment of the parts. It was tedious, but worth the effort to see how things would work. I'm now building them using fixtures to align and hold the parts for easy assembly.

Thank you for the positive comments. I'm building up a few of these planar tubes and adding small tweaks to them. Next week I'll seal some of them and finish the processing. Using different grid ladder spacing and the number of parallel filaments will be the main tests. I have no test results for these tubes yet, but the performance should be good. Since these tubes will be different design-wise from what else is out there, we'll have to see how the numbers turn out. I'm interested in seeing how well the calculations compare to the actual curves. I'm not aiming for replica tubes because I can now make triodes to a meet a wide variety of applications.

As far as the commercialization of these tubes goes, it's not the goal right now. My interest is in showing hobbyists how to make their own tubes. It can be done and at least 3 early attendees to the Workshop have started to organize their own tube labs at home. They now know that the 'impossible' is actually quite doable.

Frantz - These would be good questions to ask at the tube making forum. The link (as posted above by user211) is: http://diyvacuumtubes.com/