The Dynaco Tube Audio Forum

Would you like to react to this message? Create an account in a few clicks or log in to continue.
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


3 posters

    VTA ST-70 BOM question

    BruceB
    avatar
    BruceB


    Posts : 5
    Join date : 2009-03-03
    • Post n°1

    VTA ST-70 BOM question Empty VTA ST-70 BOM question

    Post by BruceB Mon Mar 23, 2009 8:42 pm

    Finally got around to ordering parts for the board, and got an obsolete/unavailable from Mouser on the six trim pots. Any specific things I should watch out for on a substitute?

    I found some Bourns that are single turn, cermet, 10%, 1/2 watt, blah blah blah... but they are only rated 300V.

    Bruce
    • Back to top
    Bob Latino
    Bob Latino
    Bob Latino
    Admin


    Posts : 3262
    Join date : 2008-11-26
    Location : Massachusetts
    • Post n°2

    VTA ST-70 BOM question Empty Re: VTA ST-70 BOM question

    Post by Bob Latino Tue Mar 24, 2009 7:51 am

    Bruce,

    If you are using the VTA driver board > the four DC bias controls are Mouser PN 594-63P503. You can use for the 10K AC balance controls Mouser PN 594-63P103T7. These controls see very little voltage - less than 100 volts.

    Bob
    • Back to top
    BruceB
    avatar
    BruceB


    Posts : 5
    Join date : 2009-03-03
    • Post n°3

    VTA ST-70 BOM question Empty Re: VTA ST-70 BOM question

    Post by BruceB Tue Mar 24, 2009 6:28 pm

    In that case, I can use the Bourns pots. They have the top adjust and not the side, which would be pretty interesting to use on the VTA board.

    I ordered this style:
    652-3386R-1-103LF
    • Back to top
    Bob Latino
    Bob Latino
    Bob Latino
    Admin


    Posts : 3262
    Join date : 2008-11-26
    Location : Massachusetts
    • Post n°4

    VTA ST-70 BOM question Empty Re: VTA ST-70 BOM question

    Post by Bob Latino Tue Mar 24, 2009 6:55 pm

    Bruce,

    I could be wrong here BUT > I believe you have ordered the wrong part? The Bourns "3386-R" has the pins in a line. I think what you want is the "3386-P" which has the correct triangular shaped pin alignment for the VTA driver board. See photo below.

    Bob

    VTA ST-70 BOM question VTApot
    • Back to top
    BruceB
    avatar
    BruceB


    Posts : 5
    Join date : 2009-03-03
    • Post n°5

    VTA ST-70 BOM question Empty Re: VTA ST-70 BOM question

    Post by BruceB Tue Mar 24, 2009 8:27 pm

    Wouldn't be the first time, lol, and you are so right. I can be creative and make them work until I can replace them.

    I guess it's better to find out now before they arrive (they've already shipped)
    • Back to top
    Roy Mottram
    Roy Mottram
    Roy Mottram
    Admin


    Posts : 1839
    Join date : 2008-11-30
    • Post n°6

    VTA ST-70 BOM question Empty DC bias and AC balance pots for VTA70 PCB

    Post by Roy Mottram Sat Mar 28, 2009 9:27 pm

    the correct part to use is Bourns 3386P or equivilent
    Mouser has them
    652-3386P-1-503LF
    652-3386P-1-103LF
    • Back to top
    Sponsored content

    Sponsored content


    • Post n°7

    VTA ST-70 BOM question Empty Re: VTA ST-70 BOM question

    Post by Sponsored content

    • Back to top
      Current date/time is Fri Apr 19, 2024 4:21 am