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Guitar circuit mods: Do these cancel each other out?

Discussion in 'Guitars' started by Guitarfreak, Jun 24, 2010.

  1. Guitarfreak

    Guitarfreak Well-Known Member

    I have a volume mod to each of my volumes which consists of a 330k resistor and 1000pF cap between the first and second lug. I want to put a capacitor across the pickup to roll off some highs. The capacitor will go from the input lug where the hot lead is to the exact point where the pickup cold lead/ground is. Since the cap across the pickup is there to cut the highs and the cap across the pot is there to preserve the highs I think trouble could arise. What do you think?
  2. moonbaby

    moonbaby Mmmmmm Well-Known Member

    Are you familiar with "spontaneous combustion", GF? There are capacitors out there that can K I L L you !!!
    And here you go, messing with nature and the natural order of things , just in the name of tone. Every time I read one of your posts, I pray that you survive the outcome of your project. Does your mother know what is going on in the house with your guitars and electronic experimenting ?
    Not much help, was I? :)
  3. Guitarfreak

    Guitarfreak Well-Known Member

    LOL. Overreacting a bit much aren't we? I am sure that a capacitor in an amp could and would cause some serious harm, something with a bit of capacitance, but what I am working with is about 100 picofarads hahaha. That's not even at the level of static cling I think haha. I ended up soldering a resistor across the outside lugs of the volume pot (because I got bored waiting) although I may play with the value on the resistor a bit. A little dark, but it's much better now! Anyone suffering a bright pickup should definitely try this mod.

    What mama don't know can't hurt her.
  4. Boswell

    Boswell Moderator Distinguished Member

    I'm with Moonbaby here - I think the whole thing could easily go up in flames.

    You see, if we're talking about coil pickups rather than piezo acoustic pickups, then we're in a danger area, as coils have inductance, and when you connect a capacitor across the coil you get a resonance. This resonance tunes into the frequencies of the universe and amplifies these unknown effects to such an extent that the amplitude becomes uncontrollable, very quickly causing a conflagration.

    To be on the safe side, I would try an EQ pedal to get a feel of how much roll-off you need at what frequency. It's easier then to translate that back to the components around the volume pot to see what needs to be adjusted there.

    Or, if you are totally happy with what you have done, leave it as it is until next week.
  5. Guitarfreak

    Guitarfreak Well-Known Member

    Hehe, you know me all too well.

    That is good, I guess it is good that I went with the method that I did instead of the capacitance method. The resistor on there right now is 1m, which brings me down to 333k on the pot and although the JB's earache treble is gone I fear that I am losing just a small bit of pick attack. I may try a 2m to bring the pot value up to 400k for better results. I like the idea however of going to 450k by using a 4.5m resistor. It's so close to 'standard' that I should be able to get close to pro tones with it, but should be enough difference to cater the pickup more to my individual liking :D

    Maybe GF should be added to something more than just my initials?
  6. Guitarfreak

    Guitarfreak Well-Known Member

    Wait, I thought about this today and it makes no sense. You both said that when you add capacitance to the inductor circuit you get resonance which can lead to astronomical incapacitation. However, whenever you plug in a cable, you are showing the inductor a capacitative load. What gives?

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