Confused about gain: phono + pre, or just phono?

KAB sells pre-amps and phono pre-amps -- is their calculator then based on their own as-designed input sensitivity of 325mV (not 375mV, I mistyped above)? The question then is, is the 325mV "standard" or do some target a 500mV input sensitivity (or something else)?

I've sent a note to KAB trying to understand their formula.

So, according to the website, too much gain results in increased levels of noise being passed up into the system. Seems to be the case that they'd recommend under-powering, at least a bit, so that getting to the volume you want, you'd be turning the knob on the pre-amp, which means that any noise being injected would be a function of the pre (or the rest of the system) and not compounded with the noise of the phono.

Does that even make sense?

My point is that if you "underload" the preamp (load it to 325mV max instead of 500mV max, IF 500mV is its sensitivity) you will get less S/N ratio out of the preamp (less input signal with the same noise floor of the preamp = smaller S/N ratio).
You say that KAB tailors the calculation for their OWN preamps, with 325mV input sensitivity.
This makes perfect sense and only proves my theory that if your preamp has 500mV input sensitivity, thus you should use an outboard phone stage with 66dB gain to raise the output voltage of your cart.
Thus apply the mere definition of dB to get the needed gain to raise your cart output voltage to the sensitivity level of the preamp you'll be using. That's all I'm saying.
There are two variables to use in the formula, the output of the cartridge AND the input sensitivity of the targeted preamp that will receive the output of the outboard phono stage.

Ok, I got it.

I guess the "magic number" then is the input sensitivity on the pre-amp. Which assumes that the manufacturer actually knows it. LOL.

FWIW, Robert Harley's post on this (here: http://www.avguide.com/blog/taking-the-guesswork-out-phonostage-gain) seems to indicate that it's 1v you should be targeting, not .5v nor .325v.

So, what is the deal with that number? And how do I found out what I have? Is "input sensitivity" called something else?

Usually 1V is the starting input sensitivity of power amps. The ones with loads of power will have higher numbers in here or else you won't get to turn your preamp's volume knob too much before being blasted out of your seat.
So I guess that it goes this way.
1. you have the cartridge and know from its technical specs what its output voltage is.
2. You have/intend to buy a preamp and you know from its technical specs what the line input sensitivity is. Usually 500mV (but I might be wrong here). This is not the sensitivity of the preamps' phono stage which you'll bypass if it already has one. You want to buy an outboard phono stage, right? Because either your preamp doesn't have one or the one it has doesn't satisfy you.
3. Now you use optimal_outboard_phono_stage_gain = 20*log(Vpreamp/Vcart) where Vpreamp is the line level input sensitivity of the preamp and Vcart is the output of the cartridge.
4. Of course it's not going to be the end of the world if you're a bit off, that's why I said "optimal_outboard_phono_stage_gain".
5. Take a look here: http://en.wikipedia.org/wiki/Line_level
Might see them MAX for consumer electronics at 0.447V