Cartridge Internal Impedance / DC Resistance
Internal impedance and DC resistance describe how the cartridge generator’s coils oppose electrical current, measured in ohms (Ω).
DC resistance applies to steady current. Impedance describes opposition to an alternating signal and includes coil effects that depend on frequency. The two figures can therefore differ without either being wrong.
Cartridge Internal Impedance / DC Resistance — Cartridge
These internal properties interact with the external load to affect the signal reaching your phono input. The cartridge’s coil value is not the load setting.
Compare DC resistance with DC resistance, or impedance at the same stated frequency. Keep any per-channel designation and units: 1 kΩ means 1,000 Ω. Do not assume an omitted test frequency.
Choose the input setting from the cartridge manufacturer’s recommended load and your phono equipment’s instructions. Copying the coil value, or always multiplying it by ten, is not a universal matching rule.
Sources
- AT-VM95E manual: coil impedance, resistance and load — Audio-Technica
- Impedance measurement and frequency effects — Analog Devices
- Cartridge loading: electrical model — Hagerman Technology
- AT-OC9/III manual: impedance and load conditions — Audio-Technica
- MC Samba technical data — Ortofon