Value of a preamp?

+1 @soix also it gives you the ability of various inputs, sound level balance, and control of your system components.  Ideally, it should “get out of the way” in terms of sound and noise but it’s personality can add quite a bit to a system given the right match. A definite must in my opinion, but the minimalists out there would disagree. In the end, it your system and what please your ears that counts. 

@yoyoma26  " the reality is that any source component that can drive a power amp effectively has a preamp in it. So it depends on how good a preamp you want."

Excellent point.  If your source already has an excellent internal preamp, you might or might not benefit from a separate preamp.   When people say that they do or don't get benefits from a preamp, it would be really helpful to specify what source, amp and speakers they are using.

I'm currently using a PBD MPS-8 without a preamp, using the variable volume control and XLR cables direct to AGD Duet amps, and YG Hailey 2.2 speakers.   Sound quality is excellent, but I'm curious what effect a preamp might have.   

Paul McGowan of PS Audio has posted several YouTube videos on this subject.  You can Google those.  I was going directly from my PS Audio Directstream DAC Mk1 into my M700 monoblocks,  and thought it sounded great.  After watching his videos,  and reading various other discussions,  I  decided to try putting a preamp into the chain.  About that time,  PS Audio was coming out with their new Stellar Gold Preamp,  and I was given the opportunity to beta test one.  The improvement was remarkable! Soundstage was wider and deeper,  greater detail,  just more musical in every way!! And it's a ss preamp.  Your results may differ,  but it sure improved my system.  And BTW,  many who have tried the new Stellar Gold Preamp and compared it to the BHK Preamp (which has a tube input stage) preferred the ss Gold Preamp. 

When I added my external DAC (Gustard X26 Pro) to my Parasound P6 pre A23+ amp based system I stopped using the pre remote to control the volume as I was intrigued with checking out all of the different settings on the DAC. Based on another discussion here I set the DAC volume at 100% (so that the DAC digital volume circuit isn’t involved) and went back to just using the preamp to adjust volume and SQ improved.

I don’t mean to suggest that the Parasound pre is exceptional (I am in the process of deciding on a tube pre to audition once I replace my amp (probably with a Bryson 4b3), but offer this anecdote as to one benefit of a preamp Inhave recently observed)

@kmcong ...PS Audio was coming out with their new Stellar Gold Preamp, and I was given the opportunity to beta test one. The improvement was remarkable! Soundstage was wider and deeper, greater detail, just more musical in every way!! And it’s a ss preamp. Your results may differ, but it sure improved my system. And BTW, many who have tried the new Stellar Gold Preamp and compared it to the BHK Preamp (which has a tube input stage) preferred the ss Gold Preamp.

Did you get a look inside the Stellar Gold Preamp by chance? I followed along with the design and designer a bit on this one, and keeping an eye on it into production. There are several stages and various components going on in there, looking inside.

For those who don’t believe a good preamp (adds or removes) anything, take a look inside this one. What I first thought might be a simple preamplifier design, was a very incorrect assumption. Imo, using a DAC with a decent volume control won’t usually hang in the sound department, compared to a system with a really good active preamplifier in the mix. It seems good preamps aren’t totally dead yet.