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    ST-120 to ST-70 conversion?

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    ST-120 to ST-70 conversion? Empty ST-120 to ST-70 conversion?

    Post by Guest Fri May 29, 2020 11:08 am

    There is no doubt I have high voltage spikes, which have caused damage to 3 rectifier tubes, and blew fuses on my variac. My electric voltage runs at an average at 122 to 127.3. I would prefer not to use the variac, is there a way that I can convert my ST-120 to a ST-70?
    peterh
    peterh


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    Location : gothenburg, sweden

    ST-120 to ST-70 conversion? Empty Re: ST-120 to ST-70 conversion?

    Post by peterh Fri May 29, 2020 11:33 am

    music wrote:There is no doubt I have high voltage spikes, which have caused damage to 3 rectifier tubes, and blew fuses on my variac. My electric voltage runs at an average at 122 to 127.3. I would prefer not to use the variac, is there a way that I can convert my ST-120 to a ST-70?
    The easiest and most reliable way to convert a vta-120 to a vta-70 is to sell
    the vta-120 and buy a vta-70. Conversion would be expensive ( mains transformer)
    and risks of failure.
    Best would be to seek contact with someone that would like to exchange
    his vta-70 to a vta-120.

    But the trouble with high mains voltage remains even if you change to a vta-70.
    Why not get a step-down transformer that reduces by 6 - 8 volts ?
    I have seen participants on this fora presenting their step-downs here, they
    might even build one for you !

    Bob Latino
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    Location : Massachusetts

    ST-120 to ST-70 conversion? Empty Re: ST-120 to ST-70 conversion?

    Post by Bob Latino Fri May 29, 2020 7:00 pm

    music wrote:There is no doubt I have high voltage spikes, which have caused damage to 3 rectifier tubes, and blew fuses on my variac. My electric voltage runs at an average at 122 to 127.3. I would prefer not to use the variac, is there a way that I can convert my ST-120 to a ST-70?

    If your line voltage varies from 122 to 127.3 VAC, then you need a variac to drop your line voltage into a safe range (116 - 121 VAC). Yes - a VTA ST-120 is more sensitive to higher line voltages than a VTA ST-70, but a the ST-70 will also have problems with your higher line voltages. Get a variac OR a power conditioner that puts out a true sine wave. The power conditioner will be a lot more expensive. The 5 amp variac at the link below will work fine with your amp ..

    Variacs at Circuit Specialists

    Bob

    Sponsored content


    ST-120 to ST-70 conversion? Empty Re: ST-120 to ST-70 conversion?

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