Monday, November 24, 2008

Tom Kipgen's Tube Radios


Tom Kipgen makes and sells radios
. Considering they are built by hand and quite lovely, the prices are very reasonable.

Radio Moscow

This set was started because I needed to create something that could use this great big triangular variable capacitor that I saw on eBay a couple years ago that I thought I just-had-to-have. So it's been sitting on my shelf staring down at me every day since then with that just-got-to-use-me look on it's plates. What the heck do you do with a cap that's 7" tall and 5" on three sides?

It just figured that the set would have to be triangular too. Then the thought occurred that the tube's plate cap could also mimic the variable capacitor if it was great big and had great big fins as well. Why it's the shape of a poppy bulb I don't know. Well, actually, it's more like those funny hats sitting on buildings in Moscow. It IS big though and cut from solid 2" diameter brass bar and it IS heavy.

Using a triangular surface for components is a problem because most of the area is taken up by the coils leaving little room for things like the regen knob, phone receptacle, antenna/ground connections and tuning knob. In this case the tuning knob presented a particular problem since the variable cap is mounted vertically underneath the coil. These facts did not occur to me until it came time to find a spot for them all.

The answer was a timing belt and timing pulleys and a big flat knob of Padauck wood. Padauck was also used for the bottom and upper plates and was finished with flat lacquer.

Wires from the stator and rotor travel through a plastic tube in the rear from the bottom to the top plate. This helped to keep the capacitor view clear of extra clutter.

Since everything had to be so Big there was no choice but to use the old 1625 tube schematic from Dave Schmarder to make this stuff hum. Like the others, this one operates with a 12 volt dc wall wart that is included. No need for batteries or complex multiple voltages nor anything dangerous. Heck, I had to use that big 1625 tube to hold that monster plate cap up with!

I work for minimum wage with these sets but this one really piled on some hours. Engineering required thinking and that to me is like watching pop-corn settle through a tall jar of molasses. Days and days. Boring too! Those precision timing pulleys and belts are made of gold ... well, not really but they are priced as such. That plate cap was cut from over 2 pounds of brass ... have you priced brass lately? Boy do I like to whine! If this thing sells then I want my pound of flesh and my pound of flesh costs $327.00 American!