Eurocrack opamp

Testing of opamps for Eurocrack module

• see Nurdspace eurorack raspberry pi hat

method of testing

• sine wave from Doeper A-147 VCLFO module

• schematic for +/-5V to 3.3V in breadboard

• most opamps were tested with a 33k resistor from output to inverting input of the opamp. the best opamp was also tried with 30k ohm.

• most opamps showed clipping

TL072

• datasheet: https://www.ti.com/product/TL072

LM358P

• datasheet: https://www.ti.com/lit/ds/symlink/lm358b.pdf?ts=1657890916144

MCP6002

• datasheet: https://cdn-shop.adafruit.com/datasheets/MCP3008.pdf

Also tried with 30k resistor as with 33k, the ADC used (MCP3008) clipped too much: