1970 One Tube Superhet

1970OneTubeThe plans for this one-tube receiver appeared in the Fall-Winter 1970 issue of Electronic Hobbyist, a special issue put out by the publishers of Elementary Electronics.  Even though it’s a one-tube set, it’s really the functional equivalent of the “All American Five” five-tube receiver, whose reign was just ending about that time.  The one tube employed was a 6M11, a triple tube consisting of two triodes and a pentode.  The three sections of the tube acted as local oscillator, IF amp, and AF amp.  The detector was a 1N34 diode, and the rectifier was a solid-state bridge rectifier.  So as one-tube broadcast radios go, this is about as sophisticated as they get.

As revealed by the picture, the author concedes, “we didn’t attempt to make the front panel an artistic masterpiece. You may want to make yours more attractive by restyling the dial plate and /or the speaker grille.”

“New old stock” examples of the tube are available at a reasonable price.  The parts that might prove to be unobtanium are the loopstick antenna, oscillator coil, and IF transformer.  If you have an old AA5 that’s beyond repair, the best course of action might be to scavenge them from it.

1970OneTubeSchematic

 

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2 thoughts on “1970 One Tube Superhet

  1. Daniel

    It was called, The Unicorn, and I built one in the Summer of my 12th year (1973). I was able to buy most of the parts at Lafayette Radio Electronics, Long Island, NY. Thanks to the infinite patience and kindness of the local TV Shop proprietor (where I made a regular teenage pest of myself), I had access to chassis punches and test equipment for aligning the finished set. (Thanks, Paul!- I have never forgotten you. You have influenced me more than you’ll ever know!)

    1. David Sligar

      Good story, Daniel. The parts cost more, now, LOL! I have a similar history, though my projects was an ARC 5 40 meter ham transmitter instead of superhet receivers. I’m building one of these now, to install in an old Majestic radio whose output transformer I fried. Never too old to make mistakes!

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