Stermarc,
Murph and others are correct. The "average" moving-magnet (MM) phono cartridge output is typically about 5 millivolts--that's 5 one-thousandths of a volt. Phono preamps may vary somewhat in the amount of gain they apply to a MM phono cartridge input, and you'll often find the phono level below that of other inputs, especially CD players or tuners.
The dedicated phono equalizer Murph refers to is called the "RIAA" curve (Recording Industry Association of America), adopted decades ago to standardize the amount of treble boost and bass cut applied during record cutting (then reversed during playback through the phono preamp) by different record labels.
Previously, standards varied from one company to the next. (The first hi-fi preamp I built for my dad in the 1950s had separate Rolloff and Turnover controls for different record companies.)
You might well try your NAD preamp instead of the Yamaha phono preamp. Plug the NAD into any of the line-level stereo inputs, NOT into the Phono input. The NAD might have more gain than the Yamaha, and you could adjust the Nad preamp output level to match those of your other inputs. By the way, a moving-coil (MC) phono cartridge requires yet another stage of gain applied because its output is miniscule, in microvolts (ten-thousandths of a volt). You usually only find MC inputs on dedicated separate preamps or upper-level receivers.
Regards,
Alan
