Do I really need a preamp?

In terms of gain you don't need one. And having no preamp will make your stereo sound more lively but only a touch. What a tube preamp does really well amongst other things is allow you to voice your system. If your speakers have a benign impedance curve (if they're 8ohms nominal they probably do) the linestage in your preamp will have the greatest influence on the overall sound which is really handy; you can swap out relatively inexpensive nos tubes instead of endlessly buying new speakers, amps or sources trying to get the sound you're after. I try to get everything as neutral as possible apart from the preamp's linestage. So yeah, chalk me up one vote for a tube pre.

How can a preamp better the input signal from a DAC or anything else? Wouldn't this be classified as "Coloration" since it must alter the original sound to be "Better?" Of course better is in the ears of the beholder.
I use a Benchmark DAC 2 HGC running balanced Audioquest Sky cables.
I also have another pair of Sky so I could experiment with this very thing.
I think going through an extra set of interconnects affects the sound in and of itself. My reference is taking the DAC straight into an Aesthetix Atlas driving a pair of Vandersteen Quatro CT's. I have tried the ARC REF 5 (my normal preamp before this computer audio experiment) and there's a slight decrease in resolution with a slight added tube coloration when it is in the loop. Some would probably call this better sound but it is a definite coloration to me. Guess you go with your own ears but just my take.

Robcentola hi,

Almarg (Al) is correct, technically, going direct and using the built in digital volume control of your Dac2, in my opinion will be the most transparent/dynamic way of getting the sound from your source to your speakers, without added colourations of a preamp.

If you find after doing it you would like to "voice " that sound a little, then for no cost you can position your speaker a touch differently
eg: toe them in or out a little, or move them closer or further from the back wall.
Or for some cost you can try different interconnects or speaker cable.

These suggestions are far cheaper than taking a punt on a preamp that costs $K's in the hope it has the right set of colourations for you, as they do all sound different to each other, because they all have their own set of colourations.

Cheers George

When I mentioned to my dealer that I would try my CD player preampless into my amps, he told me I would probably lose a little midrange. 2 years after living with a preampless system, I added a preamp. Dealer was right. I was robbing myself of some pretty sweet (missing) midrange. I dont think anyone should make the decision to go w/o a pramp w/o trying a preamp.

you can find great sound with either methods . For the budget inclined it is not necessary . Just do not need to get newcomers to this hobby thinking that they need to spend huge amounts of money on a preamp to get great sound.