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tone control on passive basses

Discussion in 'Pickups & Electronics [BG]' started by dadodetres, Sep 7, 2005.


  1. dadodetres

    dadodetres

    Dec 19, 2004
    URUGUAY
    hi!

    i wonder how can i calculate the frequency were a tone control starts to cut, and how many dB/oct does it cut.

    what information i have to know?


    the basses i want specifically to know are fender jazz (70`s) and warwick passive MEC system


    thancks!
     
  2. Go here...lots of information...

    http://hyperphysics.phy-astr.gsu.edu/hbase/electric/filcap.html
     
  3. DavePlaysBass

    DavePlaysBass

    Mar 31, 2004
    CO
    I use a circuit simulator to look at the response from the pickups out. This does not simulate the pickup response or the strings or the body wood etc.

    You need to know the pickup inductances and resistances and how the two pickups are wired relative to each other (series, parallel). You need to know the pot values and the load makes a difference. A passive bass sees a cable capacitance load, a active bass sees only the preamp input load which is usually a very light load.

    Here is a tone pot varied on a Jazz Bass driving a 20' cable passive with 250K pots and a 47nF cap.

    [​IMG]

    Dave
     
  4. A9X

    A9X

    Dec 27, 2003
    Sinny, Oztraya
    Thanks for doing this. Since I stopped worling full time as an EE, I've lost access to sims and the like and I'm too lazy to learn new ones. A graph makes it much easier to explain than words.

    I also shrank it as a .jpg and shoved it in my Gallery for you to link to if you need it. I'm still on dial up (for the next day or so) and big files are sloooooow, and I hope I'm not out of line doing it, but it's easier to use this than hundreds of words or a scribbled sketch.

    http://www.talkbass.com/photopost/showphoto.php?photo=1929&size=big&password=0&sort=1&cat=500&page=1

    There's a similar tone control thread running at the moment where I'll post it too to try to explain.