Dumb question......why do you need a preamp?

The first step in amplification where you take a very small signal from a dac, cd player, or turntable into a big enough signal, line stage, to be recognized by the amplifier is a very delicate and specialized task that is often neglected. This task is done by the preamp. It can be incorporated into an integrated amp or a dac without the proper attention or resources it deserves. As someone who posted here, if you try a proper preamp, you will have your answer. Once that first step is done, how good or how bad, there is not much even the best amplifier in the world can do. So, in theory, preamplification to line stage is more important than amplification if you believe in the proverbial garbage in, garbage out.

Wow! Nominated for best 1st post...in recent memory?

Well done and thank you sir.

For dacs, unless R2R has analog output no volume control, chip dacs or those with digital volume control bit stripping is the issue.

All integrateds are a compromise. That doesn’t mean they don’t sound good, there are quite a few that do sound good. I’ve owned many integrateds since the late 70’s, and have owned more separates during this same time.

Why I say this, quite a few of my preamps had separate chassis’s for the power supply, what integrated do you know of that has a separate power supply for the internal preamp section. Since external power supply’s are a good thing for a standalone preamp, an integrated shares the power supply between the preamp/amp/dac/phono preamp sections. 
 

I got rid of my latest standalone preamp when I got rid of my tt and Otari r2r and now only do digital. My dac controls the volume going directly to the amp. The designer of the dac has stated that the dac sounds better when you can get the volume up into the 80’s setting or higher. This is easy to do with the attenuation feature built into the dac. And yes, I auditioned/tested my digital sound quality going thru a high priced preamp or going directly to the amp.

You only need a preamp if you wish to add "color" to your sound.  Otherwise, if you do not have these: a volume control and/or selectable input device will be enough.