[sdiy] Module Placement - Dist > Filter or vice versa

[Scott Gravenhorst]

"Roy J. Tellason" <rtellason at blazenet.net> wrote:
>On Thursday 18 November 2004 12:26 am, William Berzinskas wrote:
>
>> i'm building a simple efx unit using a few things lying around..  i've got
>> 2 distortion units  selectable via switch..   one is tube overdrive sim and
>> the other strait distortion.   i'm also going to add a cd4007 based filter
>> in there..
>
>What kind of a filter can you base on a 4007?

Pretty much like a 4069UB filter.  The 4007 contains three inverters which can
be used as integrators.  If the input is sufficiently attenuated, you can also
use a 4007's N transistors as voltage controlled resistors.  (the attenuation
required is no worse than that used for OTA filters).  I'm still sitting on a
design myself, 4069UB for the integrators and H11F1 for the resistive
elements.  Schematic is done, gotta get my ass in gear and breadboard the
thing.  I chose H11F1 rather than 4007 or 4069 because the H11F1 eliminates
virtual ground problems AND the H11F1 distorts symmetrically (when driven with
more than 100mv Vds) according to my own testing.



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