Not signed in (Sign In)

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

Building And Troubleshooting WTPA: Changing resistor values for the R-2R section

Bottom of Page

1 to 5 of 5

  1.  
    • CommentAuthorErik
    • CommentTimeJul 18th 2010
     
    I'm currently building a second WTPA based on the bare V 1 board. The r-2r DAC specifies 59k and 118k resistors, which are not easy to find (for a fair price). Is there any reason why I couldn't substitute the values for 10k-20k or 75k-150k combos? None of the r-2r descriptions I read discussed absolute values and their drawbacks)
    •  
      CommentAuthoroootini
    • CommentTimeJul 18th 2010 edited
     
    you can solder the values together from resistors you do have, yeah.
    •  
      CommentAuthorrosch
    • CommentTimeJul 18th 2010
     
    in germany i couldn't find them at all, got them from this guy (very very fast):

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400014621943&ssPageName=ADME:B:EF:US:1123
    • CommentAuthorErik
    • CommentTimeJul 18th 2010 edited
     
    Thanks for the link. I bought both missing values from the guy.
    •  
      CommentAuthorToddBailey
    • CommentTimeJul 19th 2010
     
    For posterity, Erik is right. As long as the ratio is 2:1 and high enough impedance to be driven from the latch, any value is fine. WTPA2 uses 25.5k and 51k resistors.

1 to 5 of 5

  1.