The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    New to Dynaco

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    hogwylde09

    Posts : 6
    Join date : 2017-03-27

    New to Dynaco

    Post by hogwylde09 on Sat May 20, 2017 12:24 pm

    But not tubes. Have had tube guitar amps for years. I purchased this ST-70 for not much cash. I feel I got a great deal, considering
    the mods, test as new, xf4 Mullards, Amperex Bugle Boy EF86's and
    And McIntosh Mc75's C20 and MR66 w/stereo multiplex
    Thought I would add a picture of a ST-70 and a few questions along the way.
    First off, I believe this amp has the 2 1/8 taller laminated PT. Could I run larger output tubes? I know the quad cap would need
    replacing first. And have not had a chance to pull the bottom cover, to check out wiring, or if the selenium has been replaced.
    Second question the EF86 driver board, early Curio design? Any help on identifying it would be appreciated.
    The amp sounds great. I have the McIntosh C20 and MC75's preamp running Belle Klipsch (front), and the ST-70 running Klipsch
    CF-4's (rear). I didn't believe my ears, when it all balanced out perfectly!
    ,
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    hogwylde09

    Posts : 6
    Join date : 2017-03-27

    Re: New to Dynaco

    Post by hogwylde09 on Sat May 20, 2017 12:41 pm

    [url= photo Dynaco ST-70.jpg[/url]
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    hogwylde09

    Posts : 6
    Join date : 2017-03-27

    ....and this was given to me by my son-he builds boutique guitar amplifiers. He bought a nice stash NOS tubes, lady threw these in the deal

    Post by hogwylde09 on Sat May 20, 2017 2:22 pm

    Very Happy  photo 946.jpg
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    hogwylde09

    Posts : 6
    Join date : 2017-03-27

    Something built by a deceased audiphile many years ago. Also free

    Post by hogwylde09 on Sat May 20, 2017 2:56 pm

    [url= photo 660.jpg[/url]Got these homemade Karlson design speakers thrown in the same $50.00 deal also


    Last edited by hogwylde09 on Sat May 20, 2017 3:02 pm; edited 1 time in total (Reason for editing : image did not load)
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    PeterCapo

    Posts : 635
    Join date : 2008-12-05

    Re: New to Dynaco

    Post by PeterCapo on Mon Jun 12, 2017 9:09 pm

    There might be some markings on the bottom of the board.  It doesn't look like any of Curcio's boards pictured on his Dynaco Doctor website.  Besides, Curcio likes to use transistors with the tubes, and there's no sand jumping out at me from your photo.  My vote is that it is an earlier version of Sheldon Stokes' (SDS Labs) board sold by Triode USA http://www.quadesl.com/pdf/st70board_ef86.pdf

    At some point in its history, Sheldon's board was altered a bit to accommodate a broader range of tubes, but the basic circuit should have remained the same or similar.  As long as yours is functioning properly, it should be a fine-sounding board.  I have not heard this board but over time have read some very positive comments by others.

    By the way, discussion should probably be posted in the Basket instead of here in the photos section.

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    Re: New to Dynaco

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