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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

    Post by ricohman on Sun Feb 17, 2013 7:58 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


    Nearly done here.














    All the parts I removed.


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

    Posts : 220
    Join date : 2013-02-10

    Re: Pics of my rebuilt Mark VI's

    Post by Maintarget on Sun Feb 17, 2013 8:06 pm

    Nice work looks like your ready for years of enjoyment!

    ricohman

    Posts : 11
    Join date : 2012-12-24

    Re: Pics of my rebuilt Mark VI's

    Post by ricohman on Sun Feb 17, 2013 8:07 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.

    ricohman

    Posts : 11
    Join date : 2012-12-24

    Re: Pics of my rebuilt Mark VI's

    Post by ricohman on Sun Feb 17, 2013 8:08 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.

    Thx1326

    Posts : 5
    Join date : 2009-07-18

    Re: Pics of my rebuilt Mark VI's

    Post by Thx1326 on Sun Jan 29, 2017 5:26 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.
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    Bob Latino
    Admin

    Posts : 2583
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Pics of my rebuilt Mark VI's

    Post by Bob Latino on Sun Jan 29, 2017 6:33 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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