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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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    k40y capacitors

    kost
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    kost


    Posts : 35
    Join date : 2009-05-12
    Age : 60
    Location : athens
    • Post n°1

    k40y capacitors Empty k40y capacitors

    Post by kost Sun May 09, 2010 6:39 am

    Hi
    I am missing some treble with the new k40y caps in my
    VTA.
    Do you think that this is a matter of breaking in?
    The sound is richer than with the AURICAPS,with
    a slight loss of treble so far.
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    Bob Latino
    Bob Latino
    Bob Latino
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    Location : Massachusetts
    • Post n°2

    k40y capacitors Empty Re: k40y capacitors

    Post by Bob Latino Sun May 09, 2010 9:18 am

    kost wrote:Hi
    I am missing some treble with the new k40y caps in my
    VTA.
    Do you think that this is a matter of breaking in?
    The sound is richer than with the AURICAPS,with
    a slight loss of treble so far.

    Hi Kost,

    You have to give those Russian caps some break in time - 200 hours or more of playing.

    The treble of the Russian K40-Y caps is so smooth and "effortless" that you may think there is a loss of treble but it IS there. After they break in, the treble and the extreme low bass will increase just a little. (IMHO) The Russian caps sound much more natural and more tone correct than Auricaps. Auricaps sound a little thin to me. The Russian caps are also less expensive and usually higher volt rated than Auricaps. Russian caps are 630 or 1000 volt rated. Either the 630 or the 1000 volt rated Russian caps are more than enough with a good margin of safety. Most Auricaps sold are 400 or 630 volt rated. The ones that are 400 volt rated IMHO are not high enough rated for their intended use as a main coupling cap. I know of one case where a 400 volt Auricap blew in a VTA boarded ST-70 amp. You should only use the 600 volt versions as coupling caps in a Dynaco amp. The only good thing that Auricaps have going for them is that they are small and easily fit into tight spaces. Give the Russian K40-Y's a few more weeks to break in ....

    Bob
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    kost
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    kost


    Posts : 35
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    • Post n°3

    k40y capacitors Empty Re: k40y capacitors

    Post by kost Sun May 09, 2010 10:59 am

    Thaks Bob

    I will give the K40 a try.
    What is the best coupling for the VTA,even if it is
    expensive?
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    Bob Latino
    Bob Latino
    Bob Latino
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    • Post n°4

    k40y capacitors Empty Re: k40y capacitors

    Post by Bob Latino Sun May 09, 2010 11:04 am

    kost wrote:Thaks Bob

    I will give the K40 a try.
    What is the best coupling for the VTA,even if it is
    expensive?

    Kost,

    Probably the best coupling cap out there are the "V-caps" but they are very expensive. Russian Teflon caps are also very good but on any Dynaco driver board they are usually too large to fit the situation. Teflon caps are also more expensive than the K40-Y PIO (paper in oil) caps.

    Bob
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    Bugs
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    Bugs


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    Join date : 2009-04-17
    • Post n°5

    k40y capacitors Empty Re: k40y capacitors

    Post by Bugs Sun Jan 23, 2011 2:53 pm

    I swapped out the Auricaps in my VTA ST70 with K40Ys. The Auricaps that came with my VTA kit were .33uf and I put in .22uf per the schematic that came with the VTA instructions.

    I'm not sure if the rating difference between the two types of caps would make much of a difference, but I sure like the K40Ys. I'm running Gold Lion KT66s and in triode mode they are very smooth.

    Like Bob has described, the sound of the Auricap is thin compared to the K40Y.
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