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

Showing 2 responses by rgodin

Just about every CD player, even expensive ones with a volume control use a cheap pot or digital attenuator and possibly a set of opamps. It's better to use the fixed output and control the volume with any number of good quality passive preamps or standalone attenuators.
Wadia's site clearly states that there a loss of resolution unless the digital volume control is run at maximum (no attenuation). The more the attenuation, the higher the loss of resolution. If your amp has average gain and your speakers are more than average in efficiency, you are going to have the volume much closer to the bottom of the settings than the top.

I wasn't able to find a discussion of Musical Fidelity's volume control on their site. Is there a link ?

If transparency is what you want, then test driving a Placette passive might be worth the effort. It's not overly expensive, but supremely transparent and your money back if you don't like it. www.placetteaudio.com