Yo Eveningsky. I think the analogy holds fairly true, as many other factors than simple amplification figure into the desirability of a preamp. While appearance may not be a masjor factor, the usability and ergonomics of a preamp may be very important to the end user. For instance, does it need to be rack mountable? Does it have vu meters or LED indicators? Digital out or analog only? Does it have channel inserts so FX/compression can be added before the main gain stage? Does it have separate input and output gain control, or trim? Is the gain control in steps, and how big are those steps? Does it have variable impedence? Do you need high-Z DI circuitry? Does it offer compression or EQ? Does it have bass cut filters, and is that preset, or variable? How much gain can it provide, and at what signal to noise ratio? How agressive are the pads?
For instance, if you want to use your preamp with an unbalanced unit such as an RNC compressor, it is very handy to have channel inserts. If you are hearing impaired, as I am, accurate vu meters and a lot of headroom are a big plus. Like guitars, preamps have a wide variety of features that users simply prefer, or not.
Finally, No, it's not just a box with meters that adds gain to a signal without changing it. It is the heart and soul of your signal chain, and the sound that comes out of it *is different* than the sound that goes into it, and that is what you pay for in a high-end preamp. Nobody put a tube or a transformer into a pre to make it reproduce a signal with no alteration. A mic preamp is *not* a reference amp made for driving monitors. It is made to change the sound of the input on purpose, hopefully for the better.
Some preamps are cleaner than others, and my recommendation for a first major league preamp would tend toward the clean side. But, highly valued preamps like Neve, Great River, Pendulum, etc. are chosen because of the way they change sound, not because of the way they *don't* change it. One of the best analogies I ever read, and I don't know who's idea it is, is that the microphone is like the artist's brush, and the preamp is the paint.
The contrast between cleaner and more colored preamps exists at all levels in the price point spectrum, and a high end preamp is not necessarily cleaner than an inexpensive one.
CHEAP- clean-DMP3 colored-VTB-1
MID-PRICED- clean- Grace 101/RNP colored- Joemeek VC1Q
HIGH END- clean-Avalon AD2022 colored- Neve/Great River
These are just a few examples, and different ears will have very different opinions about how clean or colored a given preamp is, and that may vary depending on the mics and settings used. But- even the cleanest mic preamps have plenty of color, or they would suck. The point of a mic pre is not just to raise signal strength, but to define how that signal will sound. That's why you have to find the pre(s) that will define *your* sound.-Richie