State Variable Filter By Helmuth E. W. Lemme ?

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

  1. I've read a article By Helmuth E. W. Lemme at

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

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


    Is there SVF schematic which suitable for electric bass?
  2. 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. 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
  4. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    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.