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selectable input gain

Discussion in 'Effects [BG]' started by bass_fish, Sep 23, 2008.


  1. bass_fish

    bass_fish

    Oct 26, 2006
    the Netherlands
    Hey Guys,

    I'm building a new pedalboard(for the fourth time or so....) and I have an extra hammond box lying around, and a couple of input jacks, so it got me wondering of building a box where I could leave all the cables coming out of the board to be left plugged in, so I only have to plug in my bass cable and the cables to my amp...

    slight problem: I have passive and active basses, and I want 2 input jacks, one for passive and one for active, would it be sufficient to just solder a transistor(/resistor?) between them so that I have a normal, unaffected input and one that has less gain?

    if so: which transistor(/resistor?)?

    if not: how would I do this?

    Thanx!
     
  2. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    A resistor is what you want, and yes it would work. The value of it would depend on your signal level. What I'd do is get a pot, say a 100K linear (though other values of pot would work), put it in series where the resistor would go, and adjust the pot until the level is where you want it. Then use a multimeter to measure the value of the pot, and select a resistor of that value. If you don't feel like buying a pot and a DMM, then you could just buy a few different values of resistor and experiment to see which ones get you close. Resistors are cheap.

    Note: if you just connect the jacks together with no switch, then you cannot leave two instruments plugged in at the same time. Doing so would make the passive bass sound like crap, and might affect the active one as well, due to loading.
     
  3. bass_fish

    bass_fish

    Oct 26, 2006
    the Netherlands
    I don't plan on leaving the basses plugged in at the same time, so I wouldn't need a switch right(do have them laying around the house... so it wouldn't be a problem to put one in anyway)

    but I also could just use the (on/on)switch to select the resistor, right? so one side would be no resistor and the other side would be a resistor...

    I'll just buy some resistors and try some stuff out, just as easy....

    thanx
     
  4. bass_fish

    bass_fish

    Oct 26, 2006
    the Netherlands
    if I happen to have some 100K linear pots laying around, I wouldn't even need a resistor right?
     
  5. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    A pot is a variable resistor. :)
     

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