.0047 cap on jazz bass?

Discussion in 'Pickups & Electronics [BG]' started by Mikaelbass, Apr 13, 2014.

  1. Title says it all...

    Anyone ever done this? I could imagine it giving the jazz bass an interesting tone similar to a rick.

    Ive got a jazz bass with model j pups in it atm, and would definitely consider doing this mod! But I may have to go back to single coil jazz pickups for it to really shine.
  2. A 0.0047 μF cab would be quite light in effect, much less of a treble cut than the standard 0.047 μF.

    I can't see it giving you a tone similar to a Rick, simply too many other factors which are different and give the Rick the Rick sound.

    It could still work, caps are cheap enough, try it out :)
  3. tedsalt

    tedsalt Supporting Member

    Aug 5, 2010
    Kansas City
    You might try a multi-cap switch with a no-load tone pot. I put one in my p bass using .1uF, .047uF, and .01uF. Turning the pot all the way to the detent essentially bypasses the tone pot, so there would be no roll off whatsoever.
  4. You can throw an inductor in there too, if you want to play about a bit more!
  5. keb


    Mar 30, 2004
    He's talking about wiring a .0047 cap *in series* with the bridge pickup, not replacing the tone knob cap. Wiring a cap in series with a pickup rolls off lower frequencies as opposed to the treble rolloff of the traditional tone circuit. This is part of what gives old Rickenbackers (and newer ones with the Vintage push-pull knob) that bright clanky sound.

    And from what I understand, the cap in that spot can also shift the phase of the pickup it's associated with by 90 degrees, leading to less comb filtering and less mid-scoop when both pickups are on together.
  6. Ah, well I guess the title didn't say it all then :p
  7. iiipopes


    May 4, 2009
    I've done this. A .0047 in line has little bit too much bass cut. BUT...try a .01 instead. The reason for a .01 instead of a .0047 is the lesser string excursion at the bridge for a J bridge pickup as compared to the Rickenbacker 4001/3 bridge pickup; and the .01 will let just enough bass through that it will still sound like a J bridge pickup, not choked.

    As a bonus, it will eliminate the impedance drop that is typical of a pair of J pickups full on together. I do this on all my basses that have a J bridge pickup or another pickup in the same location.

    I got the idea to use a .01 from my Rickenbacker 4002. That's right: "2," not "1" or "3." It has a bridge pickup in the same position as a J bridge pickup, and a .01 inline capacitor instead of the standard .0047 as on the 4001/3.

    The only drawback is that the pickup may need to be adjusted closer to the strings, as there could be a slight volume drop when wide open compared to not having the inline capacitor. So if you really like and use a bridge solo tone a lot, you might want to switch out either the bridge pickup volume control or tone control with a push-pull to have the .01 capacitor either "in" or "out," depending on your preference.
  8. jallenbass

    jallenbass Supporting Member

    May 17, 2005
    Bend, Oregon
    For those of you who have also done this - I get a 60 cycle hum with both pickups on when the cap is engaged. Disengage the cap and it goes away. Any ideas? Normal?
  9. keb


    Mar 30, 2004
    Sounds like the cap is doing the phase shifting thing I mentioned earlier. Shifting one pickup's 60 cycle hum out of phase with the other and thus it's not being cancelled out when both pickups are on as it normally would with no cap.
  10. jallenbass

    jallenbass Supporting Member

    May 17, 2005
    Bend, Oregon
    That's kind of what I suspected. It's fine though. Not that noisy.
  11. iiipopes


    May 4, 2009
    Increasing the value from .0047 to .01, I have not noticed any extra hum. Of course, I use humbucking pickups anyway: DiMarzio Ultra J, and others.
  12. bassbenj


    Aug 11, 2009
    Extra hum is normal with single coil pickups. You should have not hum with humbucking pickups.

    The reason is that on a jazz bass with single coil pickups when both are on full the two pickups function as a humbucker. But when you put the cap in series you block low frequencies from the bridge pickup. When you do that the lows now do not get through to cancel with the neck pickup and you get single coil hum just as if you'd soloed the neck pickup.

    If your pickups are humbucking dual coil then the hum is already cancelled BEFORE the signal gets to the cap so the single coil hum effect is not there.
  13. iiipopes


    May 4, 2009
    Yes, that has been my overall experience from playing and rewiring basses for almost 40 years. Good explanation that I should have included.

    In addition, there are two types of noise: the 60 Hz hum, as discussed here on this thread, and electrostatic noise from badly filtered mains voltage, neon or fluorescent lights, other electronic devices in the vicinity, etc. Good shielding will help get rid of that noise as well, whether in the form of foil or carbon paint in the pickup cavity, or a metal cover on the pickup that is grounded, or even just turning down the tone control on the bass a number or two.