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The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


    Shielded power cord ?

    Scott R
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    Scott R
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    • Post n°1

    Shielded power cord ? Empty Shielded power cord ?

    Post by Scott R Sat Jun 11, 2011 10:45 am

    As the kit I received from Bob has a 16AWG unshielded power cord I assume is adequate for the amp or Bob would have included a different type of power cord. I have seen both in this forum and others people using shielded (in some cases rather pricey) power cords for their amps. I must be missing the point as to why this is necessary. I know that the wiring in my home isn't shielded and am curious what advantage there is to having say 6 feet of shielded cord from the wall to the amplifier would be.

    On that note I am also curious why the power cord is not grounded. Again I have seen many people add a ground (shielded or not) power cord to this and other amp kits.

    In summary why use a shielded power cord, is it necessary, is it unnecessary? Why use a grounded power cord, is it necessary, is it unnecessary?
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    Bob Latino
    Bob Latino
    Bob Latino
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    Join date : 2008-11-26
    Location : Massachusetts
    • Post n°2

    Shielded power cord ? Empty Re: Shielded power cord ?

    Post by Bob Latino Sat Jun 11, 2011 11:18 am

    Hi Scott,

    That 16 gauge two wire AC cord included with the VTA ST-70 and ST-120 amp kits is 13 amp rated. Since the fuse blows at 3 amps on the ST-70 and 5 amps on the ST-120, the included cord is quite adequate for its intended purpose.

    The original ST-70 came with a two wire cord. You can, if you want, replace the two wire cord with a 3 wire cord and ground the third wire to the chassis. The only warning here is that if any other component in your music system also has a 3 wire cord, you could set up a "ground loop" and the hum level could increase. You could try the three wire cord and note if there is any increase in hum level. If there is, just remove the third wire inside the amp. A shielded AC power cord is not necessary and will have no influence on the amount of hum/noise that the amp may have.

    As a side note > The VTA M-125 monoblock amps do use a detachable 14 gauge 3 wire cord rated at 15 amps.

    Bob
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    Scott R
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    Scott R
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    • Post n°3

    Shielded power cord ? Empty Re: Shielded power cord ?

    Post by Scott R Sat Jun 11, 2011 1:04 pm

    Thanks for putting that to bed so to speak.
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