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    Finished my VTA ST-120

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    MV213

    Posts : 12
    Join date : 2017-11-04

    Finished my VTA ST-120

    Post by MV213 on Mon Apr 02, 2018 10:45 pm

    This is a quick cellphone shot of my ST-120.  I finally got my variac and new rectifier tube on Thursday, and finished up my mods today (too many other projects going...)

    Here's what I changed:  Moved the inputs to the back where they belong, moved the power switch to the front where it belongs, added a set of ebay digital bias meters, built a custom power supply for said meters, and extended the TDR LEDs to the front panel (changed out to red and blue LEDs).  I drilled out the little board that the VTA inputs were mounted on and used it for the LEDs.    The slide switch (mono/stereo) is now a DPDT used to switch the meters between the front and rear set of output tubes.

    I really could not stand those ugly sockets on the front of the chassis, along with the inputs.

    I honestly thought I had come up with a new and original mod but I found a thread on here where somebody did something similar with the TDR LEDs a few years back.   Rolling Eyes  Oh well.

    I was not best pleased with the condition of the chassis when I got it, there were a lot of scratches/gouges in it especially on the top and ends--a surprising amount actually.  However I had originally planned on doing a Front Panel Express faceplate so I let it go.  I may still do that.

    Overall a great kit, great support from Bob, and a really nice amplifier that I think will be around for years.  A lot of fun to build.   Hope the picture works.  I used the insert photo tool and just get a little square.  I also copied the link next to it..  Maybe my google photo settings aren’t right?

     https://photos.app.goo.gl/VOLrexrK1llGKwJg1


    Last edited by MV213 on Tue Apr 03, 2018 1:08 pm; edited 3 times in total

    MV213

    Posts : 12
    Join date : 2017-11-04

    Re: Finished my VTA ST-120

    Post by MV213 on Tue Apr 03, 2018 1:06 pm

    avatar
    Maintarget

    Posts : 226
    Join date : 2013-02-10

    Re: Finished my VTA ST-120

    Post by Maintarget on Tue Apr 03, 2018 10:40 pm

    Nice job really like your modifications more pictures of the mods and wiring?
    Are you using the supplied tubes?

    MV213

    Posts : 12
    Join date : 2017-11-04

    Re: Finished my VTA ST-120

    Post by MV213 on Wed Apr 04, 2018 12:37 am

    No, I got Russian Tung-Sol 6550’s and 5AR7, and some NOS Conn organ 12AU7’s all from eBay. I think the Conns are actually Sylvania but not sure. My first rectifier tube was a new “Mullard” that failed the second time I powered it up. I’ll have to look at my camera tomorrow to see if I remembered to take a pic of the wiring before I buttoned it up. I may have forgotten.
    avatar
    Maintarget

    Posts : 226
    Join date : 2013-02-10

    Re: Finished my VTA ST-120

    Post by Maintarget on Fri Apr 06, 2018 3:54 pm

    I have some CONN 12BH7 that I really like good quality tube with nice bass, You might want to look at the yellow sheet mod for the rectifier it will help with the longevity of your rectifier tubes.

    Maintarget.......

    MV213

    Posts : 12
    Join date : 2017-11-04

    Re: Finished my VTA ST-120

    Post by MV213 on Fri Apr 06, 2018 4:16 pm

    Thanks, Maintarget. I actually did the yellow sheet rectifier mod while I was waiting for my new rectifier tube and variac. I ordered 4 of the Conn organ 12AU7’s so I do have a spare one.

    MV213

    Posts : 12
    Join date : 2017-11-04

    Re: Finished my VTA ST-120

    Post by MV213 on Sat May 05, 2018 11:32 am


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