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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


    Finished My 2nd Dyna / VTA ST-70 Upgrade

    knotscott
    knotscott

    Posts : 34
    Join date : 2019-12-28
    Location : Rochester, NY

    Finished My 2nd Dyna / VTA ST-70 Upgrade Empty Finished My 2nd Dyna / VTA ST-70 Upgrade

    Post by knotscott on Sat May 02, 2020 11:10 pm

    Here's the 2nd of my two original Dyna to VTA ST-70 upgrades.   This one was a factory wired version.  The factory rivets made getting things off the chassis a bit harder, but was otherwise pretty much the same process as the first build.

    Finished My 2nd Dyna / VTA ST-70 Upgrade 000_3614
    Finished My 2nd Dyna / VTA ST-70 Upgrade Vta711



    The two amps are now in a vertical bi-amp configuration, and sound wonderful together.  I had a few bugs to work out on the 2nd amp.  About the time I sorted everything out, a new porblem popped up on the first amp that been working great for about six weeks.  Once that problem was fixed, my old Lazarus preamp acted up and needed to be recapped and some new resistors installed.  All's well with the system now, and am happy to say it's never sounded better.  There are some definite improvements with the bi-amped setup...especially with separation and soundstage.  After some experimentation, I'm using EH EL-34s on the mid/tweeter channels in triode, and Nesstone EL34s on the woofer sides. There's a powered subwoofer hooked up too operating below ~ 50hz.

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    Finished My 2nd Dyna / VTA ST-70 Upgrade 000_3712

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    tuberadios69

    Posts : 4
    Join date : 2012-09-02
    Age : 66

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    Post by tuberadios69 on Sun May 17, 2020 12:52 pm

    They look great but I'm not so sure I'd keep them in a cabinet. Are you using muffin fans to pull the heat out? Even with the doors open I'd imagine it gets really hot in there. Also, what are those teenie looking interconnects you are using? Are they shielded and do you know the gauge. i'd want to use somewhat "beefier" IC's (IE-larger gauge conductors, solid core preferably). Just MHO, though. Again, they look great and you did a great job cleaning them up!

    knotscott likes this post

    knotscott
    knotscott

    Posts : 34
    Join date : 2019-12-28
    Location : Rochester, NY

    Finished My 2nd Dyna / VTA ST-70 Upgrade Empty Re: Finished My 2nd Dyna / VTA ST-70 Upgrade

    Post by knotscott on Thu May 21, 2020 4:48 pm

    tuberadios69 wrote:They look great but I'm not so sure I'd keep them in a cabinet.  Are you using muffin fans to pull the heat out?  Even with the doors open I'd imagine it gets really hot in there.  Also, what are those teenie looking interconnects you are using?  Are they shielded and do you know the gauge.  i'd want to use somewhat "beefier" IC's (IE-larger gauge conductors, solid core preferably).  Just MHO, though.  Again, they look great and you did a great job cleaning them up!

    I do have a couple of small PC fans inside to pull air through.  According to my decorator (aka "the wife"), my options are in the cabinet or in the basement!

    The interconnects are solid silver that I picked up years ago.  They're not shielded, and aren't overly beefy, but I've always loved the way they sounded on thoese amps.  I experimented with several a long time ago, but now that the amps have the VTA mod, maybe I'll experiment again one of these days.

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