Henry 2KD-2

Discussion in 'Amateur Radio Amplifiers' started by N0RU, Nov 16, 2018.

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  1. N0RU

    N0RU Ham Member QRZ Page

    Looking to chat with any current owners of this amplifier. I have one that I'm considering returning to life as it needs a new HV power supply and repair of missing/butchered circuitry. I did find a reasonable copy of the manual but as with many old Henry amps, circuit changes may not have been reflected in the later manuals. I have everything I need to build the HV PS but wanted to see if anyone has some details that might help in the restoration. Cosmetically it is not bad and it would be a nice amp for a small AM set-up. I have plenty of spare 3-400s and would consider going to 3-500s with some chassis mods. Any info would be appreciated. Contact me at N0RU@arrl.net.


    Robb NØRU
  2. N0RU

    N0RU Ham Member QRZ Page

    Well I suppose the lack of any replies indicates that these amps have been retired a long time ago! This should be a good winter project along with the possibility of finishing a 4-1000 home brew 160 amp that also came form a friends estate. 73, Robb.
  3. W9GB

    W9GB Ham Member QRZ Page

    Henry Radio 2KD-2 (Desk, 2 piece) was manufactured from 1965-67 using two 3-400Z glass tubes.

    James Corville, W7RY posted photos (Photobucket) of his Henry Radio 2KD-2 Amplifier
    http://s900.photobucket.com/user/w7ry/library/Henry 2KD-2 Linear Amplifier 3-400 Tubes?sort=3&page=1
    Robb -

    RadioDan (W7RF) relocated from Los Angeles to Northern Colorado in 2007.
    He got his Novice license, WN9JFO in Chicago six months before my exam (WN9MKT).
    He has worked with and distributed Henry Amps for a LONG TIME.
    He’s just “up the Front Range” from you.

    Radio Dan
    Daniel Magro , W7RF
    6493 Thompson Drive
    Fort Collins, CO. 80526
    Telephone: +1 970 295-4200

    Last edited: Dec 2, 2018
    KD2ACO likes this.
  4. W1QJ

    W1QJ Ham Member QRZ Page

    I believe this is the model which is doomed to use 3-400 tubes unless it is modified to lower the tube sockets. Not even the new style 3-400 or the very old style 3-500 will fit. Only the old style 3-400's will fit. If you want to run 3-500's (recommended) you will have to do some modifications. Other than that it is a pretty straight forward design.
  5. W9GB

    W9GB Ham Member QRZ Page

    Lou -
    IF the W7RY photos (photobucket) are carefully examined, you will see that the two (2) glazed ceramic sockets (3-400 or 3-500 usage) have been lowered.
    http://s900.photobucket.com/user/w7ry/library/Henry 2KD-2 Linear Amplifier 3-400 Tubes?sort=3&page=1

    This was accomplished by using “Z” metal brackets. These can be fabricated OR often found in well-stocked hardware stores (window and screen dept. good place to look).
    In the Radio-TV shop era, H.H. Smith or Keystone Electronics likely stocked for metal radio chassis work.

    RadioDan or Henry Radio MAY have exact part in stock.
    Last edited: Dec 3, 2018
  6. W1QJ

    W1QJ Ham Member QRZ Page

    Yes, on closer inspection I see that. That would have to be done to accept 3-500 tubes.
  7. N6UH

    N6UH Ham Member QRZ Page

    My 2k is from the same era but has SK-410 sockets which appear to be lower to start with and I suspect allow more air past. I have 1 original 3-400 and a later taller one. I don' t have a 3-500z to try but it looks like it would go in with the shorter anode cap. The other problem I can foresee is that the taller 3-400 is a lot closer to the top of the chimney so any bigger tube would need a change of chimney or the socket lowering to avoid a loss of airflow. That doesn't appear to be an issue with the OP as he has "plenty" of 3-400s
  8. AC7S

    AC7S Ham Member QRZ Page

    Ok can u use a single tube in this amp and have the same wattage out ? Running a pair of 3-500 now.
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Of course not.:)

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