State Variable Filter By Helmuth E. W. Lemme ?

Discussion in 'Pickups & Electronics [BG]' started by eutgard, Apr 1, 2010.


  1. eutgard

    eutgard

    Joined:
    Jul 13, 2005
    Location:
    Seoul, Republic of Korea
    I've read a article By Helmuth E. W. Lemme at http://buildyourguitar.com/resources/lemme/

    I think his SVF (State Variable Filter) is active form of Varitone circuit.

    I'd like to hear experience of this kind of filter.

    And...

    Is there SVF schematic which suitable for electric bass?
  2. slyjoe

    slyjoe Supporting Member

    Joined:
    Jun 28, 2008
    Location:
    Valley of the Sun (AZ)
    I don't have experience with what you are talking about. The article describes an active circuit - but it really has nothing to do with a varitone circuit. By definition, a varitone is passive.

    Maybe I'm not sure what the question really is.
  3. eutgard

    eutgard

    Joined:
    Jul 13, 2005
    Location:
    Seoul, Republic of Korea
  4. superbassman2000

    superbassman2000

    Joined:
    Dec 20, 2000
    Location:
    Minnesota
    My question for that author is how is it different from a single band semi-parametic EQ? it looks like it does the same thing
  5. SGD Lutherie

    SGD Lutherie Supporting Member

    Joined:
    Aug 21, 2008
    Location:
    Bloomfield, NJ
    Disclosures:
    Owner, SGD Music Products
    It's a low pass filter, like on an Alembic or Wal or ACG preamp. Parametric filters are band pass.

    What the low pass filter does is remove frequencies above it's cutoff, just like a passive tone control, but you can sweep it.

    I posted this in another thread. Here's a Low pass being swept followed by a high pass. A high pass passes the highs and removes the lows.

    LP/HP filter

    Also.. Varitones are NOT high cut tone controls, they remove midrange. It seems to be common to call any rotary switch a Varitone, but it's not. For instance the ToneStyler is not a Varitone, it's a decade control. it switches in different value caps.

    The low pass filter does the same sort of thing, but it continuously variable and most have a Q or resonance control that gives a peak at the cutoff frequency, so you can use that for a boost at the cutoff frequency.

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