Bandpass Gyrator Filters or almost an Octave filter

 

Bandpass Gyrator Filters or almost an Octave filter as presented by helge-h here at electro-music forum

i made 4 of these filters as part of my Matrix Mixer ,too bad that more then 6 position switches are really expensive ,but that is the only extra thing you need to expand this filter , i installed the capacitors on the switches as that makes sense to me