Here's an American Bosch model 28, from 1928, that I recently obtained and plan to restore it down the road. This is an 8-tube TRF set with two 71A's for the audio output tubes. The power cord and plug look original; but, I'll replace the cord with modern reproduction wire and reuse the original plug. One of the 71A's is branded "Mirco" (looks like a tube rebranding outfit) and is date coded 1960; so, this radio was in use at least until the '60's. Back in the early '90's, the president of our (now gone) antique radio club had one of these and I liked it. So, 20+ years later, I now own one. On his, I think he had to melt the tar out of the filter capacitor/choke assembly in order to replace the capacitors and he had to replace a bunch of wiring.
As you can see, my unit has an add on tone control accessory; which, is probably nothing more than a pot and capacitor that's wired in the plate circuit of the audio output stage.
I've got a feeling that this will be a good performing radio and I now need to be on the lookout for a nice speaker to go with it.
