LM13700 24 dB mixer circuit, TL082, TL084 op-amp based upon + – .15 9 have been working with PCB panel cizimi schema files and a detailed description has Four Pole 24dB Per Octave Low Pass Filter Log Response to... Electronics Projects, VCF 24dB Mixer Circuit LM13700 "audio control circuits, " Date 2019/08/01