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SVF filter pre with individual string pickup finished

Discussion in 'Pickups & Electronics [BG]' started by MPU, May 29, 2011.


  1. MPU

    MPU

    Sep 21, 2004
    Valkeala Finland
    I made a Wal-inspired pickup (individual coil for each string, steel core with ceramic magnet) and SVF-based filter pre (schematic found from musikding site). Here's a quick sound clip from various settings. The pre has adjustable low pass frequency and boost at cutout frequency. Both are mounted on my own custom-made graphite necked headless. Please add two more knobs to the pic.
    Sound clip at Maihinnousu - Lataa - MPU - SVF & individual string coil pickup
    DSCN0081.
    Marko
     
    SakuBass likes this.
  2. Stealth

    Stealth

    Feb 5, 2008
    Zagreb, Croatia
    Sounds very clean and very clear, Marko, I like it a lot! :D

    Which schematic did you use from musikdinger? I've been looking over the circuit but couldn't figure out which one was a SVF.
     
  3. MglMatador

    MglMatador

    May 5, 2010
    Probably this one:

    state-variable-filter_diy-layout-neu.
     
  4. MPU

    MPU

    Sep 21, 2004
    Valkeala Finland
    That one but with etched board.
    Marko
     
  5. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    Can you buy the PCB someplace?
     
  6. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Great looking bass. Only one knob? Is that the filter frequency control? Why not also have the Q control? I find those very useful.
     
  7. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    Hey, I saw mention you were working on coming out with a SVF but I don't see it on your website yet?
     
  8. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Notice that the OP says "Please add two more knobs to the pic.", and the circuit diagram shows knobs for "Resonant Frequency" and "Gain at Resonant Frequency" (aka Q).
     
  9. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    You mean I have to read the post? I just like looking at the pictures!

    :oops:
     
  10. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Yes I am. I'd not done yet, but will be soon, along with the Wal clone pickup. It's a two channel preamp with active blend and two filters, plus a "pick attack" boost.
     
  11. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    Awesome! AFAIK the only place to get them now is from some guy in Germany?
     
  12. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Thats the Lemme filter. That's the one cloned above.

    There is also the ACG/East filter preamp. That has a low and high pass filter.
     
  13. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    Ouch! on price :( . I've got some quad op amps so maybe I'll cobble something up. I really hate how pickups passively combine so maybe just a couple buffers and a combiner stage will do me :) . I actually was thinking of building a second order variable frequency LPH without variable Q when I came across the Alembic SVF and found out my idea was a couple decades too late LOL .

    Back to the OP - how did you combine the output from the separate coils in each pickup? I'd have redone the input stage of that circuit into an inverting one and summed each coil separately through a cap and resistor into the summing junction :cool: . In fact that's basically what I was going to do to the separate coils of my humbuckers to keep them from loading each other...
     
  14. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Mine will be cheaper. :)
     
  15. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    :)

    Also I'm curious if you've tried active summing of the two coils of a humbucker vs passive (serial or parallel) combining?
     
  16. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    I haven't. That's what EMG does. When I was making active pickups I had the preamp external so you could change them from series to parallel. When you do the active summing they are kind of in parallel. It cancels a lot of extra noise however.

    I'm planning on bringing my active pickups back, so I might try active summing.
     
  17. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    My understanding is that in parallel they "fight" each other and end up mid scooped with a resonant "peak". You'd get a completely different sound with active summing I think? Much flatter and perhaps needing the SVF to make it sound like a normal pickup?
    Easy enough to try and you might just nail that Alembic/Wal tone :D .
     

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