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    Help identifying ST 70 mod

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    crosseyed-cricket

    Posts : 3
    Join date : 2018-12-16

    Help identifying ST 70 mod

    Post by crosseyed-cricket on Sun Dec 16, 2018 10:59 am

    Hi all,

    I'm new to the Dynaco and tube world, and could use some help identifying this modification to an ST 70.  I've done a fair bit of searching on this forum and elsewhere, but haven't found a lot of details.

    It looks like one of the older VTA driver boards, but there are some transistors on the underside and some other things going on that I don't understand.

    Are there downloadable instructions or schematics that I could access for the older board?

    I would post pictures, but since I'm a brand-new forum member, it looks like I can't do that for 7 days.

    I've just purchased this unit and it is en-route, so I don't have it for physical inspection or testing yet.

    Thanks for any insight you can share!

    -David
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    crosseyed-cricket

    Posts : 3
    Join date : 2018-12-16

    Re: Help identifying ST 70 mod

    Post by crosseyed-cricket on Sun Dec 16, 2018 11:04 am

    I'll come back and post pics when my 'probationary' period is over. :-)
    Peter W.
    Peter W.

    Posts : 1220
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: Help identifying ST 70 mod

    Post by Peter W. on Mon Dec 17, 2018 8:24 am

    crosseyed-cricket wrote:Hi all,

    I'm new to the Dynaco and tube world, and could use some help identifying this modification to an ST 70.  I've done a fair bit of searching on this forum and elsewhere, but haven't found a lot of details.

    It looks like one of the older VTA driver boards, but there are some transistors on the underside and some other things going on that I don't understand.

    Are there downloadable instructions or schematics that I could access for the older board?

    I would post pictures, but since I'm a brand-new forum member, it looks like I can't do that for 7 days.

    I've just purchased this unit and it is en-route, so I don't have it for physical inspection or testing yet.

    Thanks for any insight you can share!

    -David

    There have been any number of driver boards over the years, some of which were quite impressive in terms of capturing auto-bias and voltage regulation. As you note, when you are able to send pictures, that will help.
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    crosseyed-cricket

    Posts : 3
    Join date : 2018-12-16

    Re: Help identifying ST 70 mod

    Post by crosseyed-cricket on Mon Dec 17, 2018 8:28 am

    Thanks, Peter. I've enjoyed reading and learning on this forum so far....looking forward to more.

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