Swan 1200-X

Discussion in 'Amateur Radio Amplifiers' started by N8SAN, Jun 28, 2017.

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  1. N8SAN

    N8SAN Ham Member QRZ Page

    Right, fully aware of the filament voltage reduction required to run these. Just wanted to be assured that these three versions will result in the same output as the original tube.
    Thank you.
  2. AF6LJ

    AF6LJ Ham Member QRZ Page

    There is more rewiring than just filament voltage...
  3. N8SAN

    N8SAN Ham Member QRZ Page

    Not trying to stir the pot, but did I miss something??
  4. AF6LJ

    AF6LJ Ham Member QRZ Page

    The 6LF6 and 8950 have the same base wiring.
    A 6KD6 is different look them up on the internet.
    Look for datasheets on both tubes, and compare the base wiring.
  5. N8SAN

    N8SAN Ham Member QRZ Page

    So the data sheets show that the only thing that matches is the 6LF6 and the 6KD6, the 6LR6 doesn't match anything.

    This is why I ask these questions, to people smarter than I am.
    My assumption is that number 6 on the 8950 being cathode, is probably important; the fact that the other 3 have NC, has me to believe it is a problem.
    Furthermore, the 6LR6 on pin 9 shows "internal connection" would also pose a problem.

    Now, what I don't understand is why the 8950 has 2 cathode pins while the others have one.
    The diagram attached to each sheet clearly shows the 8950 having a direct jumper from pin 2 and 6 while the others show nothing or the NC.

    Not according to the data sheets I've found. The actual pinout for the 8950 is unique to the 4 tubes in question. (hence my questions, perhaps I should have been more explicit)

    So why would the 8950 require the 2nd cathode connection and the 6LF6, 6KD6 and 6LR6 would not? Maybe this pin is simply not used in this situation as Steve pointed out, these are TV tubes, NOT audio communication tubes.

    Furthermore, why does every other tube have two pins for each grid, yet the 6LR6 only have one for grid 1?
    My assumption would be it has less ability to control the flow of electrons. Again, this is why I'm asking these questions. Maybe this is irrelevant.

    1. PIN 8950 6LF6 6KD6 6LR6
    2. 1 Heater Heater Heater Heater
    3. 2 Cathode Cathode Cathode Cathode
    4. 3 Grid 2 Grid 2 Grid 2 (Screen) Grid 2
    5. 4 Grid 3 (beam) Beam Plate Beam Plate Grid 3
    6. 5 Grid 1 Grid 1 Grid 1 Grid 1
    7. 6 Cathode NC NC NC
    8. 7 IC IC IC IC
    9. 8 NC NC NC NC
    10. 9 Grid 1 Grid 1 Grid 1 IC
    11. 10 Grid 3 (beam) Beam Plate Beam Plate Grid 3
    12. 11 Grid 2 Grid 2 Grid 2 (Screen) Grid 2
    13. 12 Heater Heater Heater Heater
    14. CAP Plate Plate Plate Plate

    OF COURSE my editing for this didn't work.

  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I'd stick with the tubes it was designed for.

    Changing tubes doesn't "make more output power."
    AF6LJ likes this.
  7. N8SAN

    N8SAN Ham Member QRZ Page

    No arguments there. I was only asking if they would make the same output as the 8950. The reason I'm going though this is for cheaper tube.
    If it was just heater voltage, that's not terrible.
    Even if the other tubes do not need the PIN 6 Cathode. That's easy, just plug it in, it won't go anywhere, there's no connections.

    There is a deep ingrained trait that I have, that I HAVE to know "why" it can't be done, and if it can, what needs to be done. Call it a fault. My wife does! :D:p
    AF6LJ likes this.
  8. AF6LJ

    AF6LJ Ham Member QRZ Page

    I would agree...
  9. AF6LJ

    AF6LJ Ham Member QRZ Page

    The reasons the tubes are built different has to do with their intended use, and ease of assembly.
    Some of the sweep tubes have built in fuseable links in the cathode lead to protect the circuit they are used in.
  10. N8SAN

    N8SAN Ham Member QRZ Page

    That's interesting.

    Part of MY problem with all this (meaning my want/need to understand) is that there are people out there that have used these different tubes and they worked. But clearly the pinouts do not match perfectly. So while there has to be some similarities it clearly doesn't have to be perfect.


    Like this thread.... "You want to install the 6lb6 tubes. They are a 6 volt version of the 8950 and are the same in every way. Run the filament voltage in series instead of parallel to the tubes, then go man go."
    Well, they are not! They don't share the same pinout. The 6LB6 are closer to the 6LR6 but the 6LB6 pin 11 is IC.
    But this guy swears they work....

    "continues to beat head against brick wall"

    You guys can ignore me if you'd like. :rolleyes:
    Also, in the amp Pin 5 and 6 are jumped together. Ya know, just to add more nonsense to the conversation.
    AF6LJ likes this.

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