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  • January 30, 2020 at 4:33 pm #12902
    Les Dickson
    CVRS Member

    I have some radios where the output transformers are shorted. I haven’t been able to locate any Canadian suppliers and the cost of getting some from the USA are prohibitive given the value of our dollar. These are not high end radios so I’m not wanting to invest a lot of money. So, I’m looking for information on Canadian suppliers you may know of, or other advice on workarounds.
    One needed transformer has primary impedance of 5,000 ohms and secondary of 8 ohms – single ended.
    Another has primary of 10,000 ohms and secondary of 4 ohms – single ended.

    January 31, 2020 at 1:43 pm #12903
    Ed Kraushar
    CVRS Member

    Perhaps some of the 70 line output transformers may work. Not quite their intended use but may work depending on primary voltage. They usually have a variety of taps that can be used for matching. They are usually quite cheap.
    The internet may have some data including a You tube video.
    Ed.

    January 31, 2020 at 3:26 pm #12905
    John Greenland
    CVRS Member

    Hi Les,
    I am not sure how adventurous you are but ordinary wall wart transformers will work for basic audio.
    A 120 volt to 5 volt has very close to the same turns ratio as a 5000 ohm to 8 ohm, 25 turns to 1. The 120 to 5 volt is 24 to 1 turns ratio.
    It would allow you to at least hear the audio until a proper transformer comes along.

    For the 10000 to 8 , you could use a 240 volt to 5 volt or a 120 volt to 2.5 volt transformer., or even a 5000 ohms to 4 ohms if you have one.
    The one thing to keep in mind is that they will not have the gap in the core. That can be fixed with a bit of patience.

    Good luck.
    John G.
    VO1 CAT

    February 1, 2020 at 2:29 pm #12907
    Les Dickson
    CVRS Member

    Thanks for the replies. The wall wart transformer is an interesting idea. I know where there is a good supply of them so I may give that a try. I’ll have to figure out how to create an air gap.

    February 4, 2020 at 7:26 am #12908
    Jean Marcotte
    CVRS Member

    Ed, be careful with 70V line transformers. Some are autotransformers. You don’t want to put your B+ on the speakers.

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