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ZL linear - 813 & 12A6 clamper

Discussion in '"Boat Anchor" & Classic Equipment' started by VK2CAO, Jan 21, 2015.

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  1. VK2CAO

    VK2CAO Ham Member QRZ Page

    Gidday - Does anyone have a circuit diagram of a ZL linear and operating instructions? I lost mine when I moved and want to set it up again. Any assistance would be much appreciated. It has a 1000V (not sure) solid state PSU.

    Cheers - Noel VK2CAO
  2. W1BR

    W1BR Ham Member QRZ Page

    Why are you using a clamper on a linear amplifier? I don't understand.

  3. KM1H

    KM1H Ham Member QRZ Page

    It is a huge IMD generator similar to the G2DAF amp in that regard
  4. VK2CAO

    VK2CAO Ham Member QRZ Page

    The amp and PSU were a gift from a mate. I think the clamper was used with the grid current adjustment on the front panel. I used to hook it up to my ZC1 MkII that had about 8 watts AM power, on 80m. It worked fine. I may open her up and work out the circuit myself. I had a copy of the circuit that came from a manual with other amps including some from G2DAF.

    View attachment 217008 Here's a picture

    Cheers - Noel
  5. W1BR

    W1BR Ham Member QRZ Page

  6. VK2CAO

    VK2CAO Ham Member QRZ Page

    It's not a copy. It's by ZL1AAX Lester Earnshaw.
  7. W3DBB

    W3DBB Ham Member QRZ Page

    There are schematics for the ZL1AAX and G2MA-variant amplifiers in the CQ Technical Series paperback New Sideband Handbook by Don Stoner W6TNS (1958). Pages 154 to 157. If you can find it online someplace that would be handy (and fortunate). My copy is an old original purchased for a buck at a hamfest.

    Three pages devoted to the Lester Earnshaw design, one page to the David D. Marshall G2MA design. Three paragraphs of "Technical Considerations" on the ZL1AAX design. 1000 to 2000 VDC on the anode of the 813 per the schematic.
  8. VK2CAO

    VK2CAO Ham Member QRZ Page

    I have obtained a copy of the whole book on line. The postage was more than the cost of the book. Thank you for the information

    Cheers - Noel VK2CAO
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