Equivalent Input Noise (MC)
Equivalent input noise (EIN) expresses a phono stage’s noise as an equivalent voltage at its moving-coil (MC) input, before amplification.
Figures may use nanovolts (nV), microvolts (µV), dBu or dBV. Lower voltage means less noise; with the same decibel reference, more negative means less. dBu and dBV use different references. Output noise is measured after amplification.
Equivalent Input Noise (MC) — Phono Preamp
Low-output MC cartridges produce small signals, making preamp noise more significant beside the music. Compare the MC gain setting, source termination (the impedance connected during testing), bandwidth (frequency range) and weighting (frequency emphasis in the measurement).
A shorted-input result does not represent every cartridge: source impedance affects noise. If conditions are missing, don’t rank the stages by EIN alone. Signal-to-noise ratio compares signal with noise; noise density (nV/√Hz) is not total noise over the measured frequency range. A low EIN cannot guarantee a quiet system: hum and interference can still intrude.
Sources
- RaneNote 145: Audio Specifications — Rane
- Boulder 1108 Phono Preamplifier specifications — Boulder Amplifiers
Sources
- Analog Devices AN-940: Low Noise Amplifier Selection Guide — Analog Devices
- Extron: dB to Volts — Extron