It's the level that counts.
A preamp is primarily used to bring a certain signal (e.g. from a microphone, a voice or an instrument) to the right level. This is called line level. But this is not the only advantage of a preamp. Many devices score points with musicians and producers because of their low noise or a pleasant saturation and sound colouration. Especially devices with a vintage sound are favoured. More and more manufacturers are reacting to this trend and bringing devices with historical circuit design back onto the market - based on the old legends of the recording world. Manufacturers we can recommend to you include Warm Audio, ART, SPL, DBX, RME, AMS, TC-Helicon, SSL, Royer Labs, Universal Audio, Presonus, Chandler Limited, Focusrite, Audient, Golden Age Project, Rupert Neve Design, Manley, Avalon, Antelope, Drawmer, Tube-Tech, and many more!