MM gain
MM (moving-magnet) gain describes how much a phono stage increases a cartridge’s signal voltage. It is expressed in decibels (dB).
Decibels describe amplification; millivolts (mV) describe voltage, such as cartridge output or input sensitivity. These figures are not interchangeable. The specification may give one fixed gain, a continuous range or selectable steps.
In a phono preamp
In a phono preamp, gain raises the cartridge signal for the next amplifier input. Match it to your cartridge’s output using the cartridge and phono-preamp guidance. The highest dB figure is not automatically the best choice. Too little gain can leave the output low; too much can overload and cause distortion.
Compare figures at the same measurement frequency, commonly 1 kHz, and for the same output connection. RCA and XLR outputs can have different gain figures. For a built-in phono stage, use its phono gain, not the host amplifier’s overall gain.
Sources
- Matching gain to cartridge output — Sumiko
- Gain settings and output connections (pp. 4–5) — Pro-Ject Audio Systems
Sources
- Phono gain and the 1 kHz reference (p. 2) — Texas Instruments
- Cartridge output voltage — Ortofon