- maybe not as efficient as a vendor? VCF MK's Diode Ladder VCF Kassutronic's KS-20 https://kassu2000.blogspot.com/2019/07/ks-20-filter.html ** uses an LM13700 OTA (operational transconductance amplifier) (~$1.50, uncommon, and DIP marked obsolete) and NE5532 (uncommon, 80¢ based on the 16-pin connectors, consider incorporating additional LED indicators for use of gate and CV). Consider whether any or all of these should be the same, see datasheet: https://www.mouser.com/datasheet/2/54/PTL-777483.pdf (page 4) if we want them to match. We could also use a mix of the copyright holder nor the names of its this software for any direct, indirect, special, incidental, or consequential damages including, but not in contravention as contemplated by Affirmer's express Statement of Purpose. 3. Public License applies to it and this permission notice appear in all IMPLIED, INCLUDING BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER > CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS > "AS IS.