hi bakis,

the Erwik filetr is based on the low cost Curtis 3372 combined
VCF/VCA that is also found in the budget Sequential Prophet-600,Akai
AX80 and the absolutely superb Oberheim Matrix 12. to the best of my
knowledge, there were only 15 possible variations.

1 pole Low
2 pole Low
3 pole Low
4 pole Low
1 pole High
2 pole High
3 pole High
2 pole Band
4 pole Band
2 pole Notch
3 pole Phase
2 pole High + 1 pole Low
3 pole High + 1 pole Low
2 pole Notch + 1 pole Low
3 pole Phase + 1 pole Low

do you mean to say that Doepfer will add more then the ones mentioned
above.

the filter will require at least a 2 digit display like the A113
subharmonic generator. the first digit could the filter type and the
second digit would be the memory position for the filter type from
the vc filter selection input. on the outer edges the display, you
could have the dual pushbuttons like the A113 to go up or down. now
you are probably wondering , how would get fifteen locations out of a
simple single digit display. you use the digits 1 to 9 for the one to
nine positions, you use the 0 for the number ten position, then you
add a dot at the bottom left position of the digit for the digits
over ten, i.e .1 is for eleven, .2 is for twelve etc. etc. same goes
for the memory position for the vc filter select input position.

to program the sequence of filter types for the vc filter selection
input you press the 2 vc filter selection input push buttons at
once , then the vc filter selection display starts flashing at the
number one position. you then press the up or button on the left side
for ther filter type value. to set the second vc filter select memory
value you hit the down button to set it the 2 position then you hit
the up or down on the left side for the filter type. you keep
repeating the steps to complete the sequence of the filter types.
once you are done programming, you push the two vc filter selection
input buttons at once and the flashing memory positon stops flashing
and away you go.

there is an example of what i mean for the display the files section.
hope this helps on the logic side of the vc filter selection input.

RM