The Dynaco Tube Audio Forum

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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


4 posters

    Has anyone tried using the 6u8a in place of 7199?

    j beede
    j beede


    Posts : 473
    Join date : 2011-02-07
    Location : California

    Has anyone tried using the 6u8a in place of 7199? Empty Has anyone tried using the 6u8a in place of 7199?

    Post by j beede Wed Jun 08, 2011 10:26 pm

    Has anyone tried swapping the traces under your PC-3 and then using the 6u8a in place of 7199?
    Sal
    Sal


    Posts : 221
    Join date : 2009-02-05
    Location : Central New Jersey Dynaco-ST70.com

    Has anyone tried using the 6u8a in place of 7199? Empty Re: Has anyone tried using the 6u8a in place of 7199?

    Post by Sal Thu Jun 09, 2011 7:51 am

    I have not swapped the traced on the printed circuit board but I have used the 7199-6GH8 adapter sold by Dynakitparts.com. The ST-70 is happy with a 6GH8 tube.

    Sal
    anbitet66
    anbitet66


    Posts : 143
    Join date : 2009-12-23
    Location : Valley Stream, NY

    Has anyone tried using the 6u8a in place of 7199? Empty Re: Has anyone tried using the 6u8a in place of 7199?

    Post by anbitet66 Thu Jun 09, 2011 11:55 am

    If you look at the schematic for an ST-70 series 2 it uses a 6GH8 with only 2 different capacitors in the circuit. According to what I have read about 6U8A, it is even closer to the characteristics of the 7199. If you don't want to cut and rewire for a test, the plug in converter mentioned by Sal will aslo work for the 6U8A tube.

    Or, to not have to buy the adapter, you could theoretically make your own by removing the envelope of a 7199 and carefully attach a socket to the base to plug in a 6GH8/6U8A as a test... Twisted Evil

    BTW I'm kidding; don't try this at home kids! I'm a professional. Tony
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    wolverine


    Posts : 59
    Join date : 2010-02-20

    Has anyone tried using the 6u8a in place of 7199? Empty Re: Has anyone tried using the 6u8a in place of 7199?

    Post by wolverine Sat Jun 11, 2011 7:50 am

    I purchased two of the socket converters and use them on one of my ST-70's. The board is a new one, but exactly as the original 7199 board. I used two NOS Sylvania 6GH8A tubes and it sounds fantastic to me.
    wolverine

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    Has anyone tried using the 6u8a in place of 7199? Empty Re: Has anyone tried using the 6u8a in place of 7199?

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