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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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    Pics of my rebuilt Mark VI's

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    ricohman


    Posts : 11
    Join date : 2012-12-24

    Pics of my rebuilt Mark VI's Empty Pics of my rebuilt Mark VI's

    Post by ricohman Sun Feb 17, 2013 5:58 pm

    I have finished the rebuild of my Dynaco Mark VI's. It took me a couple of months part time and waiting for parts, but they are finished.
    I measured every resistor that I removed and nearly all were out of value. The resistors that were supposed to be within 1% were not even within 20%. I found some values of the carbon comps nearly double.
    So I replaced them all, along with every film and electrolytic capacitor and the main b+ capacitors.
    Had a couple of problems when I fired them up (sticky power switch and one shorted power tube) but they are now working fine.
    Before
    Pics of my rebuilt Mark VI's DSC05038

    Nearly done here.
    Pics of my rebuilt Mark VI's DSC05113_zpsbf3b3e00

    Pics of my rebuilt Mark VI's DSC05035

    Pics of my rebuilt Mark VI's DSC05020

    Pics of my rebuilt Mark VI's DSC05120_zps52899f66

    Pics of my rebuilt Mark VI's DSC05163_zpse1924615

    Pics of my rebuilt Mark VI's DSC05162_zps032204db

    Pics of my rebuilt Mark VI's DSC05155_zpse6eef033

    All the parts I removed.
    Pics of my rebuilt Mark VI's DSC05169_zps5437f0d7


    Last edited by ricohman on Mon Feb 18, 2013 12:49 pm; edited 2 times in total
    Maintarget
    Maintarget


    Posts : 227
    Join date : 2013-02-10

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    Post by Maintarget Sun Feb 17, 2013 6:06 pm

    Nice work looks like your ready for years of enjoyment!
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    ricohman


    Posts : 11
    Join date : 2012-12-24

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    Post by ricohman Sun Feb 17, 2013 6:07 pm

    And in my tube venture I found this Stark 9-66A tube tester. I have used it to measure the gm on the 8417 output tubes in an attempt to get as close as I can to a matched set.
    Pics of my rebuilt Mark VI's DSC05045
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    ricohman


    Posts : 11
    Join date : 2012-12-24

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    Post by ricohman Sun Feb 17, 2013 6:08 pm

    Maintarget wrote:Nice work looks like your ready for years of enjoyment!

    Thanks.
    I bought these as they were the only amps I came across locally. And to tell you the truth I don't know if they are a good match with my Altec 19's. Time will tell but I think a pair of MK III would have been more suitable for my use.
    Lots of reserve power with 102db speakers.
    Pics of my rebuilt Mark VI's DSC04969
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    Thx1326


    Posts : 13
    Join date : 2009-07-18

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    Post by Thx1326 Sun Jan 29, 2017 3:26 pm

    Does anyone have a link to plans and procedure for replacing the 8147's with KT120's and updating the rectifier circuit.

    I'm thinking of restoring a pair but not going to attempt it without this info. Any help would be greatly appreciated.

    Thanks in advance.
    Bob Latino
    Bob Latino
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    Posts : 3260
    Join date : 2008-11-26
    Location : Massachusetts

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    Post by Bob Latino Sun Jan 29, 2017 4:33 pm

    Thx1326 wrote:Does anyone have a link to plans and procedure for replacing the 8147's with KT120's and updating the rectifier circuit.

    I'm thinking of restoring a pair but not going to attempt it without this info.  Any help would be greatly appreciated.

    Thanks in advance.

    Yes - Check out the link below ...

    Replace 8417 with KT88/6550

    You can also use a KT120 in a socket designed for a KT88/6550 provided the power transformer will handle the slight extra load of a KT120. In almost all cases the PT will handle the extra load just fine.

    Bob

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