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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


2 posters

    Wow freshly restored . But it now does not work s70 .

    avatar
    corey thompson


    Posts : 7
    Join date : 2023-11-14

    Wow freshly restored . But it now does not work s70 . Empty Wow freshly restored . But it now does not work s70 .

    Post by corey thompson Tue Nov 14, 2023 8:54 pm

    So i threw in all the caps on the board .
    Two caps inside the case used to be 50 volts . A new choke .
    This amp did work before restored . I do have many sets of tubes here to confirm tubes are good .
    All the tubes glow as they should . The bios adjustment does work on both channels to where i last set it .
    I am very sure the caps are soldered in tight . The choke . I am not sure if its directional or not ? Only two wires .
    I am not a rookie with a soldering iron .
    Good signal to the amp 100 % sure i used my back up amp to test .

    List of parts i used . Thanks for the brain power and help .
    FOUR of Jantzen Audio 0.22uF 1200V Z-Superior Capacitor for the top board .
    Two of Jantzen Audio 0.10uF 1200V Z-Superior Capacitor top board.
    Two of Audyn Cap Plus 0.47uF 800V Double Layer MKP Metalized Polypropylene Foil Crossover Capacitor inside case to replace those .50v
    Choke is Triad Magnetics Inductor240Ma, 50%, -20% - C-24X
    I could not find the factory in stock.
    I think some how the main board got killed . I think that is the pre amp section.
    avatar
    corey thompson


    Posts : 7
    Join date : 2023-11-14

    Wow freshly restored . But it now does not work s70 . Empty Re: Wow freshly restored . But it now does not work s70 .

    Post by corey thompson Tue Nov 14, 2023 9:53 pm

    updated . I checked current at the top caps . The 4 have about 20 volts . The two on top about 8.
    I will check the lower tomorrow when i get the proper gloves and long sleeves with rubber . Im not plating games with that 400 volt ! Makes a guys life very short if shocked .
    avatar
    corey thompson


    Posts : 7
    Join date : 2023-11-14

    Wow freshly restored . But it now does not work s70 . Empty Re: Wow freshly restored . But it now does not work s70 .

    Post by corey thompson Wed Nov 15, 2023 8:59 am

    update , i will put the factory caps back into the inside case . those .50v i think the ones i put in were so large there using all the power , ill update progress .
    Bob Latino
    Bob Latino
    Admin


    Posts : 3271
    Join date : 2008-11-26
    Location : Massachusetts

    Wow freshly restored . But it now does not work s70 . Empty Re: Wow freshly restored . But it now does not work s70 .

    Post by Bob Latino Wed Nov 15, 2023 9:49 am

    Hi Corey,

    You are a new member and cannot post a photo of your amp right now. Post a photo of both the outside of the amp and the inside wiring on the 21st of this month. Read one of the stickys on the forum on how to post a photo. Once we see the outside and inside of the amp maybe one of the members can pick up on something that could cause your amp not to work ?

    Bob
    avatar
    corey thompson


    Posts : 7
    Join date : 2023-11-14

    Wow freshly restored . But it now does not work s70 . Empty Re: Wow freshly restored . But it now does not work s70 .

    Post by corey thompson Wed Nov 15, 2023 4:45 pm

    So two caps i put into the internal of the amp. Checked for power . Going in but not out ! I hit my local store replaced them again with 75 volt caps that have the plus or minis instead of non polor .
    Problem fixed. Sound is clean detailed wide 3 d sound . The upgrade was worth it .
    avatar
    corey thompson


    Posts : 7
    Join date : 2023-11-14

    Wow freshly restored . But it now does not work s70 . Empty Re: Wow freshly restored . But it now does not work s70 .

    Post by corey thompson Thu Nov 16, 2023 12:08 am

    update . Amp works great sounds great. However . The power transformer is on its way out .
    Can see some goop and it stinks so bad . Temps on it cooking over 200f !! .
    I will upgrade it with something better . Im not sure of the name . The round transformers do sound better then the solid brick .
    Bob Latino
    Bob Latino
    Admin


    Posts : 3271
    Join date : 2008-11-26
    Location : Massachusetts

    Wow freshly restored . But it now does not work s70 . Empty Re: Wow freshly restored . But it now does not work s70 .

    Post by Bob Latino Thu Nov 16, 2023 8:54 am

    corey thompson wrote:update . Amp works great sounds great. However . The power transformer is on its way out .
    Can see some goop and it stinks so bad . Temps on it  cooking over 200f !! .
    I will upgrade it with something better . Im not sure of the name . The round transformers do sound better then the solid brick .  

    If your amp's power transformer is truly running at 200 degrees F, then it probably is bad and could fail in the near future. 140 to 150 degrees F is more like a normal run temperature. If you are going to use your amp as a "daily driver", you should replace the power transformer. Check out the forum link below where I did a test on a VTA ST-120 amp using a Cason infrared thermometer.

    VTA ST-120 temperatures

    Bob

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