Oddball tube complement

I have Sylvania, Silvertone, Cameo, and RCA radios with a 18FW6, 18FX6, 18FW6, 32ET5 and 36AM3 tube lineup. The Silvertone uses an 18GD5 and the Sylvania uses a 34GD6 output tube in place of the 32ET5. These radios were all built after 1960. Why did this tube complement come into use? I thought I remembered reading a discussion on this at one time, but I have forgotten when or where. The radios seem to all work well with those tubes. I have noticed that the input filter capacitor is fairly stout, 70uf on a couple sets.

WC

They wanted tubes that warmed up quicker without using a lot of current. Shortly after that transistors took over in most cases, though some tube stuff was still made. This odd ball line up of tubes was basically a flop.

Thanks, Bill. I seem to remember something about tube warm up time, now that you mentioned it. This tube complement just gives something a little different in my collection.

WC

I don't know if I've even heard of any of those tubes.