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5 string fretless: "Ignis 3"

Discussion in 'Luthier's Corner' started by T-34, May 11, 2012.

  1. T-34


    Aug 11, 2005
    France, Paris region
    Hello, guys, wanted to share my last build with you.
    I am building this bass for a friend, the design is of my last build 6 years ago ( :ninja: ), the 6 str fretless bass "Ignis" http://www.talkbass.com/forum/f57/ignis-6-str-fretless-singlecut-286054/

    this one will have one string less, have different woods and two pickups


    * mahogany body with imbuia top
    * roasted ash (hi temp treated) multilam neck with ebony fretboard, unlined, neck-through
    * 1 trussrod, 2 carbon stiffener rods
    * not sure what pickups yet
    * weirdo homebuilt electronics, more on this later

    you'll probably ask: where's Ignis 2? You'll be right: it is in the works but not advanced far yet :)
  2. T-34


    Aug 11, 2005
    France, Paris region
    Top wood and fretboard from LMII:

    Neck wood:

    Laminating maple separation layer to imbuia top

    Blues or Reds? ;)

    Nice figure popping out after wetting the top with some water:

    Laminating the neck (four pieces of roasted ash separated by fine maple accent layers):
  3. Very nice, T-34. I like the design, but I'm an even bigger fan of "weirdo homebuilt electronics," can't wait to see/hear! Thanks for the help last year on my own weirdo electronics, btw :)
  4. T-34


    Aug 11, 2005
    France, Paris region
    Yeah, bizarre mix of passive and active, you'll like that :D
  5. if it is going to be as nice as the Ignis 6 string, I am excited to see the rest!

    J'attends la suite avec impatience!
  6. T-34


    Aug 11, 2005
    France, Paris region
    Thank you, I (and future owner) sure do hope it turns out well!

    Mr Beauchene, do you speak french too? :D
  7. Unfortunately, no- but it's on my to-do list. My last name is by way of Canada, and I'm aware that it's a good last name for somebody who likes to make stuff out of wood ;)
  8. T-34


    Aug 11, 2005
    France, Paris region
    Proper woodworker name for sure :)

    Once I worked in Russia, company's network admin's last name was Loginov, no kidding :)
  9. hahaha
  10. Stealth


    Feb 5, 2008
    Zagreb, Croatia
    Ditto. Love the design but it's the circuitry that piques my curiosity the most. :D

    Not to derail the thread, but, Beauchene, can you link to your own wierdo electronics?

  11. T-34


    Aug 11, 2005
    France, Paris region
    So, speaking about my electronics.

    This bass will have two passive tone controls, one per pickup (home-built multi-capacitor selector using 10-position rotary switch, I call it "Megatone") followed by two-channel buffer preamp with no EQ. This way it'll be possible to use "Megatones" independently unlike in full-passive circuit where tone controls cannot be separated properly without the loss of signal.

    Here is the schematics I designed

    detailed view for Megatone part:

    normal/boost switch changes the control's behaviour a bit, I'll post simulated frequency response curves later to show the difference.
    R1 to R9 are 2Meg, needed to keep capacitors discharged and avoid "pops" when switching caps.
  12. T-34


    Aug 11, 2005
    France, Paris region
    Now the graphs,
    Top diagram showing "boost mode", bottom - "normal", each of 10 curves representing one of 10 positions of the rotary selector.


    So basically this is a low-pass resonant LCR filter, inductance L defined by pickup and C choosen by rotary selector and R by boost switch.
    Looks promising :)
  13. T-34


    Aug 11, 2005
    France, Paris region
    For comparison sake: this is what the frequency curve of conventional tone control looks like (0.047 capacitor, 250K log pot):

  14. Wow, that's really cool! It looks like a 5-10dB boost that's sweepable from 1-10k and lops off everything higher. Do you think, though, that those last two positions, as you get close to 10k, might just be letting more noise than signal through? Could you change component values to drive the whole graph left, so the 'presence' boost selection could start at 100hz? just a thought. Very freakin' cool.

    [threadjack] Stealth, joeyl posted the link, my first attempt at a preamp is about halfway through. I've changed it since then, but I'll make my own thread to tell you about it. [/threadjack]

    ...aaaaaand subbed!
  15. T-34


    Aug 11, 2005
    France, Paris region
    No, the mid boost peak cannot be moved more to the left easily, to accomplish that you'll need pickup with more inductance. I've made my simulation taking an "average" figure of 4H, that's inductance of an average PB pickup. Moodbucker or Fender '72 tele humbucker will yield about twice inductance as that, moving frequency boost one octave lower.

    About the noise at higher positions: keep in mind the baseline signal is still there, what you have is just a resonant peak boosting some produced frequencies, still letting others be there. The filter is passive so no additional noise at all will be produced (unlike traditional active EQ circuits), meaning the peak is NOT accompanied by the raise of the noise at this frequency.
  16. T-34


    Aug 11, 2005
    France, Paris region
    Back to wood stuff :)

    roasted ash and maple separators glued together; sipo body wings

  17. Ah, I see. I'm just getting more into winding pickups. I see an inductance meter in my future. Great, more tool GAS. :bag: Wood choices look great!
  18. T-34


    Aug 11, 2005
    France, Paris region
    Looks like I've completely neglected the updates in this topic...

    Will try to catch up with the updates accumulated since last time I've posted!

    June 2012
    Body wings roughly cut

    Prepping tilted headstock surface

    thinning down Imbuia for matched headstock, gluing

    Installing double-action truss rod and two carbon rods
  19. T-34


    Aug 11, 2005
    France, Paris region
    July 2012

    Gluing body wings to the neck

    Cutting rough neck shape