Not sure if this is what you meant, but this link brings me to a "4 line mixer"??
You're right, that's a line-level mixer. A [u]mixer with microphone inputs[/u] has built-in mic preamps and is generally cheaper than a preamp alone.
You can search for "differential microphone preamp circuit". [Here's one](https://www.google.com/search?q=microphone+preamp+schematic+differential+op-amp&newwindow=1&tbm=isch&imgil=3C2kl3yJp4miuM%3A%3BnuV_93Lp0bdDTM%3Bhttp%253A%252F%252Fwww.rason.org%252FProjects%252Fopamps%252Fopamps.htm&source=iu&pf=m&fir=3C2kl3yJp4miuM%3A%2CnuV_93Lp0bdDTM%2C_&usg=__zE41GYjbWHdWUt3_qAHefXNawJs%3D&biw=1280&bih=556&ved=0ahUKEwi-
Condenser mics require power. Computer condenser mics get power from the soundcard.
Note that an audio signal into the Arduino has to be biased because the Arduino can't read the negative half of an AC audio waveform.
Studio condensers get 48V phantom power from the mixer or preamp. A stage electret condenser may kYTwufDUAhXj3YMKHciYCNYQyjcILQ&ei=mPhbWb7lDuO7jwTIsaKwDQ#imgrc=jcLN0hAT_casxM:&spf=1499199885146) I just found. The actual voltage you get out depends on the sensitivity of the mic, the loudness of the sound, and the gain of the preamp. So, virtually every preamp has a gain or volume control.
Also, that schematic doesn't show the required dual power supplies (usually +/- 12 or +/- 15V).
Another point here is that I want it to be analog with standard 3.5mm connector
Note that "computer microphones" are different from stage/studio mics. Stage/studio mics are low impedance balanced (3-wire) whereas computer mics are high impedance unbalanced (2-wire).
Condenser mics need power. Computer mics get power from the soundcard. Studio condensers use 48V phantom power from the mixer or preamp. Stage electret-condensers may have an internal battery or may be phantom powered.
[u]Here is a schematic[/u] for an electret condenser preamp with power for the mic, and a biased output for the Arduino.