Zenith transoceanic and other portables with 1l6 emissions mystery

[Tubejunke]

As of late I have aquired several Zenith radios using the infamous and expensive 1L6 "converter" tube. I started with a single Transoceanic and through trial and error I destroyed a set of the very delicate 1.4VDC tubes. I use my SelectAvolt supply now to power all of these sets until I feel that they are ready for full wall current.

I want to say that Zenith did a wonderful job of making some of the most sensitive radios that I have ever seen during this "wave magnet" period of the 40s and 50s. I really love them. I can find something to listen to at any time of the day and of course night time DXing is a blast. But the reason I made this thread is that I don't understand the nature of the 1L6 vacuum tube.

As of right now I have 3 radios playing just fine. None of the 1L6s show good on two known good (very good) tube testers. One is almost out of the red (bad) area and works fine. Another is about 1/4 of the way up the red (bad) on the scale and works just as fine. The only one that doesn't work is one that shows absolutely no emissions. As good as the radios work with them, I can't help but wonder what one actually showing good would do in a radio. Perhaps better reception on the shortwave bands?

Also, has anyone ever tried one of the solid state replacements now made due to the long dwindling supply of 1L6s. I think if it works that it would be a worthy investment for anyone keeping one of these radios alive.

By the way, my other Zeniths similar are the 5G41 "Flip Top" units. Really neat little radios but only receive broadcast. I best get any good 1L6 out of those and put in the 1R5 (I think) suitable replacement that people are using in Transoceanic models. Supposedly they will allow broadcast (AM) reception, but fail to pull in shortwave which to me is no good if you have a Transoceanic radio. I mean why make one of those beauties into a simple AM radio?