Resistance it the measure we use in DC circuits; impedance is used to measure AC circuits as this value can change with frequency. Synth modules usually have their inputs and outputs defined as impedance – probably because it’s common to frequency modulate inputs.
In general, you want a low output impedance and a high input impedance. The greater the difference between the two, the less chance the input is going to affect what’s being delivered by the output. Eurorack modules tend to have an input impedance of 100k (100,000 ohms); output impedances can vary from near zero to 1k.« Back to Glossary Index