What does a pre amp do


I have been trying to get an answer to this question, but so far have not been enlightened

In a modern system, the role of a pre amp is really questionable.

Historically, a pre amp would provide quite a number of real functions such as source selection, impedance matching, maintain volume consistency from different sources, volume adjustment, mute, balance, even tone control, high/low filters

Today, most people have a single CD source with XLR interconnection, which standardized impedance and signal level. Some CD and DAC (such as wadia) has digital volume control. In fact wadia does recommend people to connect directly to their amps

At least in thoery, the best preamp is no preamp. Even the preamp manufacturers agree as evident by the extent they go to separating power supply, minimize signal path. Then there is the passive preamp

So here is the question, is preamp a historical appendix that audiophiles are afraid to get rid of due to the fear of missing out on some unknown elements of music. Or is it really a percived need created by good marketing programs to exploit audiophiles

The obvious answer may be to try it out with and without preamp in the same system. The results I have heard so far are controversial, some claims much better transparency and clarity while others claim there is a lack of dynamics and less musical

I do not believe answers from "experts" who happens to be in a sales position. They always give a very affirmative answer and yet refuse to let you do an A/B comparision.

Most modern preamps are an empty box, and do we need to pay high prices for a piece of equipment with no known function
ag007
I should add, the problems I reported on above were more with the Res Audio than the Audio Aero and I still run my Audio Aero into my tube monos. But the Res Audio runs through an SCE HRS before my Plinius SA102 - and there is no doubt the SCE HRS is worth its cost, the cost of a PC and an extra interconnect.
The stage of gain that a preamp induces is critical to complete the musical signal. Its like reversing the DNA of the signal and playing it back. (riaa curve)

Passive preamps just dont make it. People think they sound better but in the end, and on whole, they don't.

Forget the new wave of thinking, get a killer tube pre-amp and get happy.
I share your views on passive preamps. But the Res Audio players do not have a passive preamp in them. They have an active line stage that that follows the volume control and that, on paper, looks as good as any decent silly state preamp, with oodles of drive and low output impedence. Maybe it is not as good as claimed - don't know. But I find that the problem manifests itself, even with a preamp in place, if I run the Res Audios at lower than full volume. Again, I doubt you can point your finger at the quality of the volume control, but it appears more likely to be the problem than the output stage. I think I recall hearing that the volume control is the same as that used by Rowland. My theory is that when implemented in a CD player that it attracts more RF problems the more resistance is introduced into the signal path. I have that theory for no other reasons than that; one-box CD players are tricky beasts to keep digital nasties out of the analogue (which is why DVD players sound bad IMO - much more digital rubbish sprayed around inside the box); the effect on the sound increases as volume is attenuated; and, the effect sounds awfully like RF problems I have experienced at other times and in other systems.
I use my Audio Aero CD player in place of a preamp. I am of the opinion that, unless you are playing vinyl, the standard preamp is of minimal value. Really well-mixed CDs require almost no treble/bass adjustments, especially since the Audio Aero seems to already add a bit to the bass, anyway.

But here's an interesting aside. I recently had an early 1950s-era Fisher AM/FM tubed tuner restored and it has a preamp tht has multiple equalizaton settings for different LPs, depending on the label. Weird, but I guess a really senstitive preamp can have value...for vinyl.