Ultimate output of a phono preamp is determined by cartridge output and the gain of the phono stage.

Cartridge output specs are usually given as x millivolts at 5 cm/second @ 1,000 Hz, or sometimes at 3.54 cm/s @ 1,000 Hz. For the latter spec, multiply by 1.41 to get the 5 cm/s equivalent.

In consideration of a multitude of factors, but mostly the upper side of cutting level on most records, 3x the cartridge spec (15 cm/s), for peaks, is usually the most one would expect to encounter. There might be a few occasions where it could be 4x (20 cm/s) or even more, but those outliers only lasting for ~50 milliseconds (1/20th of a second), at most. More likely 20-40 ms. Which is to say, just accounting for 15 cm/s is fine.

On the high side are the Rega MM carts, claiming "6.8-7.2 mV" (I've never seen cart output given as a range before, but . . .), with no parameters given. So then, assuming (as assume we must) 5 cm/s for 7.2 mV, a max cutting level peak of 4x (20 cm/s) would bring it to 28.8 mV at input of the phono pre. For a gain of 42 dB the output from the phono preamp would be 125 x .0288, or 3.6 volts.

At more typical MM output of 5 mV at 5 cm/s, 1,000 Hz,  a peak of 4x the cart spec of 5 cm/s (20 cm/s), would be 20 mV at phono input, and 42 dB gain (125x) would have 2.5 volts at the output.

That 2V spec you are using for the Mani is only their reference for the THD spec, not a max output number. The very high numbers you cite for some other phono stages indicate what the unit is capable of, not that any cartridge would come  close to obtaining that output.

The ~344 mV RMS cited in the ARS (Amateur Scientist Review) iFi Zen report was with 5 mV input at 36 dB (63x) of the MM setting.

Edsonic:  wow, thank you for the masterclass level response!  That’s something I never would’ve figured out by reading specs, or even from contacting phono preamp manufacturers.  It’s probably only an issue for the ZRock2, this the pool of interested parties is quite small.

Based on Darko’s review saying it bests his Technics 1210GR with Ortofon Black, I bought the Pro-Ject Debut Pro with Sumiko Rainier cartridge.  The Rainier has an output of 5 mv.  And the upgraded stylus (Moonstone, Wellfleet) are 3 mv.  Based on your expert calculations, that make the output voltage 2.5V or less, and perfectly ok for the ZRock2.  Is that correct?

I have probably $6000 or so invested into my digital side, which sounds great.  I’m quite shocked that the $1000 Pro-Ject, at least on Getz/ Gilberto and Kenny Burrell’s “Midnight Blue” (the only records I own), sounds as good or better.

I spent 90 minutes getting the tonearm balanced using Pro-Ject’s teeter totter stylus scale.  Very difficult, but it did balance perfectly.  Yet when the stylus first hits the record, there’s a loud pop each time, though plays normal after that.  Is that normal for vinyl?

Thanks again.

I’m using the internal phono stage in an integrated amp, but would like to work the ZRock2 in the mix.  The records are brand new from the Verve Acoustic Sounds and Blue Note Classic series, first time ever played.

Just want to discern if the loud pop when the stylus first hits the record is normal, or if I should pursue a replacement from Crutchfield.

I’ve literally not heard a vinyl record since 1979, so I’m not sure what normal is.

Thx

Good idea, thanks.