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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


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    1K ohm Pin5 to Pin6 resistor purpose/quality?

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    vegaseddoc


    Posts : 12
    Join date : 2009-11-21

    1K ohm Pin5 to Pin6 resistor purpose/quality? Empty 1K ohm Pin5 to Pin6 resistor purpose/quality?

    Post by vegaseddoc Sat May 07, 2011 1:53 pm

    Any advantage to changing this particular resistor? Does the value have to be exactly 1K? The reason I ask is that I broke one of the originals while maneuvering some K75-10 coupling capacitors into the chassis. Please don't ask how (i.e. butter fingers). I was going to buy some new ones but I found some Shinkoh 1.2K tantalum 2 watt resistors in my stash. Can I use these or should I just buy some new metal-film resistors. Any opinions on this topic?

    Jason
    Bob Latino
    Bob Latino
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    Location : Massachusetts

    1K ohm Pin5 to Pin6 resistor purpose/quality? Empty Re: 1K ohm Pin5 to Pin6 resistor purpose/quality?

    Post by Bob Latino Sat May 07, 2011 2:31 pm

    That "grid stopper" resistor doesn't have to be exactly 1K ... You could use a 1.2K tantalum 2 watt resistor in there. I use a 1K 1 watt carbon film resistor there. Since pin 6 is not used on the EL34 family of tubes, pin 6 is just used as a tie off point to carry the audio signal over to pin 5 (the control grid) through that resistor. That resistor is in there, by the way, to prevent the tube from oscillating at some frequency and/or the possibly of the tube transmitting (unwanted) RF.

    Bob
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    vegaseddoc


    Posts : 12
    Join date : 2009-11-21

    1K ohm Pin5 to Pin6 resistor purpose/quality? Empty Re: 1K ohm Pin5 to Pin6 resistor purpose/quality?

    Post by vegaseddoc Sat May 07, 2011 3:56 pm

    Thanks. I switched them to the 1.2k resistors and the system works fine.

    Jason

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