This one followed me home. Its a COMPLETE and unassembled hardware kit for the Electronics Research Laboratories , 3 tube radio, Chigago Just how this one ended up here in New Zealand is a mystery
The box is a bit tattered, but everything is there, valves apparently were not supplied.
Here is a video clip of the assembled kit
here is what I have
I think with this one it may be far more collectable left as a kitset, rather than assembled. It really should be in a museum......
After looking through this kit of parts, its actually quite amazing the mechanicals involved, everything is built in a big and robust fashion. All components have screw terminals, so no soldering required. The audio transformers are very nicely made in their own metal sheilding containers. The valve holders are designed to screw down to a base board, 4 contacts and a bayonet fitting. Circuit wise, there is very little to it. The problem really was despite the very low gain of these early triodes, it was not possible to achieve any meaningful amount of stage gain without them becoming unstable,, especially at RF. The stage would oscillate. Any neutralization was a band aid, so heavy loading and or staggered tuning of each stage was required to keep the thing working. The selectivity was very broad, sensitivity low. The advertising standards of the 20s were very lax, so anything was a pass, buyers really had no idea what they were getting, being mislead by the advertising hype. I guess with nothing better to compare, most were reasonably satisfied with any noises it would make, being at the forefront of the technological age. More technical savvy people would probably have built/experimented with their own designs using parts available at the time with slightly better results, but requiring even more stages and money.... it was an expensive hobby. Once the screen grid valve made its appearance, radio performance really leapt ahead.
Great Post. Radio History is really cool.