Mains Transformers as Modulation Transformers

Discussion in 'Amplitude Modulation' started by G3YRO, Jun 7, 2020.

ad: L-HROutlet
ad: l-rl
ad: Left-3
ad: Subscribe
ad: Left-2
ad: abrind-2
ad: L-MFJ
  1. W2VW

    W2VW XML Subscriber QRZ Page

    BTW Phil, what you heard on 10 meters from here the other night was a pair of Antek power transformers uses as a modulation xfmr.
     
  2. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    Fantastic1

    I use Antek transformers almost exclusively now.



    Pheel
     
  3. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    As I stated earlier we tried various phasings with no success.

    I will keep asking, what is the correct schematic? Show us one that is known to work on a DX-100 or Apache or whatever and post it here on the Zed so there is no guesswork and everyone can use it and repeat the results.

    Text can be ambiguous and imprecise.

    Pheel
     
    Last edited: Jun 21, 2020
  4. WB2GCR

    WB2GCR Ham Member QRZ Page

    Attached Files:

    K4KYV likes this.
  5. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page


    Yes. that is where I got my schematic.

    The only difference is in my schematic signal flow is from Left to Right.


    The "B" schematic above is exactly the same as my schematic; point X is my Yellow or N/C wire.

    Pheel
     

    Attached Files:

    Last edited: Jun 22, 2020
  6. N2DTS

    N2DTS Ham Member QRZ Page

    You don't show the choke and cap to take the current off the secondary....
     
  7. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    What do mean "I don't?"

    No one is showing a reactor inductor nor a reactor coupling capacitor.

    The discussion is about the Turbomod modification to the likes of DX-100's and Apache's. I.e., what is the correct schematic interpretation for the Turbomod discussion at


    https://www.amwindow.org/tech/htm/dx100.htm .

    Do you have something technical to add?


    Pheel
     
  8. K4KYV

    K4KYV Premium Subscriber QRZ Page

    Just like any other modulation transformer, a turbo-connected one can be operated with or without a blocking capacitor and reactor. It may not be necessary when it's a turbo-connected modulation transformer that was designed to carry DC to begin with, but would be a practical necessity when using a power transformer, whose core is interlaced and has no gap.

    Another thing that is possible when using the blocking cap and choke with a modulation autotransformer, is to run separate power supplies for modulator and final, and thus different B+ voltages on the modulator tubes and final amplifier tubes.
     
  9. N2DTS

    N2DTS Ham Member QRZ Page

    I thought you had to take the current off the secondary.
    I tried two of the large antec toroidal transformers and they sounded nasty no matter how I connected them.
    Borgi told me you had to take the current off the secondary and I gave them away.

    Maybe its different when done as an autotransformer?
     
  10. KA4KOE

    KA4KOE Ham Member QRZ Page

    So true. Needed some new iron and TFO set me up. Good man.
     
    AC0OB and W1BR like this.

Share This Page

ad: ProAudio-1