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What effect would upping the cap value give on a passive bass?

Discussion in 'Pickups & Electronics [BG]' started by cnltb, Oct 7, 2013.

  1. cnltb


    May 28, 2005
    The subject says it all.
    I am thinking about upping the cap value on my single coil P bass from .47uf to 1uf as a friend recommended this.
    he did not tell me how exactly this will affect the bass in terms of tone and behaviour of the tone pot.
    Could/would you enlighten me on this?
    Thanks! :)
  2. LowB-ing


    Aug 3, 2005
    It will make the tone even more deep/dark when the tone knob is rolled down.

    There will not be much difference to your current one when the tone knob is all the way up.
  3. Fender32


    Jun 23, 2005
    Kent, England
    I just did this very thing to my P Bass a couple of days ago (when I found that I had a spare 0.1mf cap in my box of guitar goodies :D).

    The 0.047mf cap that I fitted when I built up the bass (it's a 'parts bass') left the P Bass sounding a little 'hollow' and thin :meh: and I couldn't figure out why, when it worked so well unplugged :meh:!? It was as if I couldn't dial enough brightness out of the strings and the true P Bass bottom end was just not within reach of the tone control.

    Now that I've changed the cap, the tone control has a lot more impact on the bottom end. Treble is eroded away nicely for the first half of the turn and then, as you get into the final third, things really thicken up nicely (without being overly muddy), until you get to '0', where the tone is deep and the treble is thoroughly muted.

    Actually, I don't know why most P Basses come with 0.047 caps, as I think that the 0.1 cap suits them much better ;).

    Just my $0.02
  4. It shifts the frequency cutoff downward.

    But you are off by an order of magnitude. 1uF would be mud. You want 0.1uF.
  5. cnltb


    May 28, 2005
    So does that mean that the higher the value, the more of the frequency spectrum 'gets Through' ?
  6. GlennW


    Sep 6, 2006
    No, it means the higher the value the more highs get blocked.

    You can experiment without cutting or soldering.
    Get another .047uF cap and temporarily connect its leads to the leads on your present cap. That will put them in parallel which will combine their values, and sound like a .1uF cap. Then you'll know if you like it. If it cuts too much treble, you can try a .022uF in place of the extra .047.
  7. Bassamatic

    Bassamatic keepin' the beat since the 60's Supporting Member

    Going to a higher (larger) value lowers the bottom frequency of the signals that get sent to ground. Doubling the value cuts the frequency in half.

    This affects all settings of the tone knob, since with the larger cap, frequencies that were not previously affected will now start to get rolled off.

    As GlennW says - you can also parallel caps (values add in parallel) to easily get in-between values - a good idea - may be easier than searching for all the different cap values.
  8. cnltb


    May 28, 2005
    What I'd like ideally would be to leave my top end intact when the tone pot is all the way open-a tone as open as possible-at least as open as I have it now with the .047uf cap, but with more 'mudd' when it's turned the other way.
    You recon that a .1uf cap might be the right choice here?


    Feb 2, 2005
    S. Carolina
  10. I have been using .087 for a while now. This seems to work best for my tastes. .1 seemed to get too muddy, but anything less didn't cut enough treble.
  11. georgestrings

    georgestrings Banned

    Nov 5, 2005
    IIRC, .1uF was the standard cap in older P Bass circuits, .05uF is a current standard... Since I play primarily with a pick, I use .1 on both my P basses and Jazzes, and it works well for me...

    - georgestrings
  12. cnltb


    May 28, 2005
    Would the kind of cap make a difference?
    Electrolytic, non-electrolytic,etc,etc,etc...
    I seem to remember a thread some time ago where this was discussed, but can't remember what the title was...
  13. MPU


    Sep 21, 2004
    Valkeala Finland
    Paper in oil for the REAL vintage guys, Orange drops for vintage guys and anything that has the right value for the rest of us.

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