fetrons... what to do with them?

Discussion in '"Boat Anchor" & Classic Equipment' started by K7WXW, Jun 11, 2019.

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  1. K7WXW

    K7WXW Ham Member QRZ Page

    I recently acquired a box of components from a ham that built a lot of Heathkit gear. He had shelves full of finished kits, spare parts, etc. In my box of goodies were two Fetrons, a TR1002 and a TR1119. I know these were sold by Heathkit as drop-in replacements for the 6AL5 and 12AU7 (I think) in one of the VTVMs.

    Wondering if anyone has a schematic of these? I've been searching the web and finding references to them but not a data sheet or specs. While I don't have a Heathkit VTVM, it would be fun to figure out how to do something with them.
  2. KL7AJ

    KL7AJ Ham Member QRZ Page

    I have a Drake R4 that was completely "fetronized." While this seems to work as well as the unmodified version, fetrons turned out to have a limited life...they were NOT eternal replacments....had to do with the FETs available at the time. YMMV
    K7WXW likes this.
  3. WA2CWA

    WA2CWA Ham Member QRZ Page

    One of the main purposes of the fetrons was to extend the life of tube based test equipment. Tubes were becoming "difficult" to find in the quantities needed. In your case, any design that uses a 6AL5 or 12AU7 the fetrons will work. Probably no real gain in using one of these things except that fetrons don't have a filament. Put them up on ebay and make a few $$. There's some up there now and lowest price is $9.95 for one.
  4. KE4OH

    KE4OH Ham Member QRZ Page

    Wow. Different times, indeed. 6AL5 are cheap and plentiful. You can get a bucket full for short money from any tube supplier. 12AU7 is still being manufactured so it is plentiful and relatively cheap. Agree - Sell those Fetrons. They are the rare item.
    N2EY and KD2ACO like this.
  5. K7WXW

    K7WXW Ham Member QRZ Page

    Thanks for the info. I imagine I will find them a new home on ebay.
  6. WB2GCR

    WB2GCR Ham Member QRZ Page

    Interesting that this comes up now... I have just acquired a few Fetrons.

    There is information on the web, takes a bit of searching. Some articles, papers, and
    websites. The basic theory and schematic of these is shown in one or more of them.

    They're high voltage FETs, not MOSFETs. Hybrid circuit.

    I'm going to try one in the front end of a particular receiver... I am expecting to find very
    very low noise.

    The short life part? I'm surprised. That may be due to some running the device at "plate"
    voltages that exceed the design target voltage?
  7. K7WXW

    K7WXW Ham Member QRZ Page

    I've done a cursory web search and found a few mentions. I will dig a bit deeper because I am always curious about "transition" technology like this but I will probably find a new home for them rather than have them gather dust around here.

    Thanks for the help all! 73 Bill
  8. WB2GCR

    WB2GCR Ham Member QRZ Page

    You've got email...
  9. KE0ZU

    KE0ZU Ham Member QRZ Page

    My 32S1 has eight of them, that were there when I bought it, and it works OK. Haven't had a problem with it so...

  10. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Here is the ARRL bibliography on FETRON's.

    • FEB 1973 - QST (PG. 48)

      Fetron--A Solid-State Tube
      (Technical Topics)

      Author: Blakeslee, Douglas, W1KLK
      Article: QST Archive [PDF]
      Keywords: TUBE
      Report a problem with this entry

    • AUG 1972 - HAM RADIO (PG. 4)

      Newest solid-state device: Teledyne Fetron
      (A Second Look)

      Author: Fisk, Jim, W1DTY
    K7WXW likes this.

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