Fretless Bass Pickups: Parallel DC , Series DC, Singles, or Split Rev-P?

Discussion in 'Pickups & Electronics [BG]' started by Aidil, Dec 4, 2016.

Which pickup wiring should I use?

Poll closed Jan 4, 2017.
  1. Parallel Dual Coil

    20.0%
  2. Series Dual Coil

    0 vote(s)
    0.0%
  3. Install push-pull pot for enabling Dual Coil series or Single Coil

    60.0%
  4. Keep using the stock MK1s

    20.0%
  1. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    IMG_20160914_232010_zpsu0x3ls6t.jpg

    This is my current go to fretless bass, the Ibanez SRF705. It has 2 magnetic Bartolini MK1 pickups and under the bridge piezo pickup. There are 3 volume knob for each pickup, 2 band EQ for both magnetic and a tone control knob for the piezo. So, essentially this bass came with tons of tonal options.

    IMG_20160914_230436_zpsqpgs1xes.jpg

    The thing is... I've just got USA Bartolini MK5CBC pickups for quite a bargain price. I don't have any problems with the stock pickups & electronics, so actually it's not a necessity buy.

    FYI, the MK5s are direct replacement for the licensed MK1 pickups and they have different coil configuration. The MK1 has split reverse-P coil inside, whereas the MK5 has full blade dual coil and can be wired as dual coil (series or parallel) or single (north or south) coil.

    WIN_20161120_08_03_02_Pro_zpsmszyvtsq.jpg

    For simplicity (as the bass already has so many tonal options), I might just wired the coils in series and be done with it. From what I've read, fretless will not get any advantages from parallel dual coil as it will result in creating mid scoop sound whereas fretless sound should be more focused on the midrange. Am I wrong?

    To enable coil switching, I need to install one or two mini DPDT siwtches. I opted not to go to this direction as I'd like to keep the bass body original, so drilling extra hole(s) for the mini switch(es) is not an option. But there is always another way... I could change the stock volume pot(s) to push-pull pot type which basically has DPDT on-on switch integrated. This way I could have the options of series dual coil or single coil for each MK5.

    The last option seems to be the direction I'm heading, but... I'm still not sure whether single coil pickups will be useful for fretless sound or will the result be worth the effort, as again, the bass itself has already came with tons of tonal options with the stock MK1 pickups, the piezo and the active electronics. I might just sell the MK5CBC.

    TB-ers, what say you?
     
  2. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    This is what I've found so far of the stock electronic diagram:

    portamento_wiring_diagram-gif.gif
    thanks for @Awesome Sauce for uploading it on Ibanez Portamento Club

    I'm really newbie here in terms of modding pots. Seems like if I'd continue with my 3rd option of installing push-pull pot for coil tapping, any push-pull 500K pot will do the job, right?
     
  3. I played only fretless for many years, and yep it's all about the midrange. I would wire them in series for sure. And yeah I think single coil would be a handy option. you'll only need one push-pull to switch both into single coil mode. make sure you switch a north coil from one pickup and a south from the other.

    use a 500KB pot. (the B means linear taper).
     
    Aidil likes this.
  4. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    thanks for the tips @RobbieK

    I'm still in the process of learning... and yeah, I've just recently learned about that B linear taper thing. Definitely have to make sure about the north and south coil when wiring them for single coil mode.
     
  5. It's super easy if both your new pickups are the same. When you wire them in series, there will be a link that you make from one coil to the other. Simply run a wire from this link into the electronics cavity. The push-pull switch will be DPDT. This means "double pole, double throw". So six lugs. The two wires you've brought through from those links will each have a pole, and when you pul the switch, one will short to earth, and the other will short to hot.

    FWIW, for volume controls, you can use either A or B taper pots, but as the diagram already shows B taper, best to go with that. (An A taper 500k pot will act very abruptly unless it "sees" a nice high impedance.)
     
  6. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    this I still don't understand...

    what have a nice high impedance that it can see?
     
  7. Most stuff these days has a 1Megohm input impedance. 500KB will be fine. This what's already there. If you are satisfied with the sweep and blending action of the two existing vol pots, there's really no need to try anything else. Using 250k pots (either A or B) will give the magneting pickups a very slightly warmer tone by damping the treble peak a touch.
     
    Aidil likes this.
  8. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    thanks for the enlightenment @RobbieK
     
  9. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    whomever that have voted for Parallel Dual Coil... would you mind to share the reasons why?
     
  10. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    another update...

    Just got myself a B500K push-pull pot. Have looked many places, couldn't find the one with solid shaft (just to match the solid Ibanez stock pots). Now I just need to pull my courage to do the soldering myself...

    IMG_20161212_102156_edit_zpswrgoxc00.jpg

    but seems like I'll just bring it to a friend luthier. :whistle:
     
  11. You should use these. The inner diameter is 6mm and the outer is 1/4 inch. You should also make sure the grub screw in your knob doesn't squash the two halves of the split shaft together. Either have the grub screw at the same angle as the slot in the shaft, or pack the slot with something.
     
    Aidil likes this.
  12. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    ah... thanks. I have no idea such thing ever existed
     
  13. vin97

    vin97 Inactive

    Mar 7, 2016
    Germany
    what kind of bridge is that?
     
  14. Aidil

    Aidil

    Dec 4, 2014
    Jkt, IDN
    Ibanez own bridge, I guess...

    They call it "Custom bridge for AeroSilk Piezo system"