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

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.

All gear has compromises including separates. I think making an assumption that separates always sound better is flawed today. When comparing separates to integrated amps today the sound quality differences will come down to design and execution, not the number of rectangular boxes. Huge power supplies with multiple chokes, big iron and coke can sized caps all in a separate chassis is no longer the only way to build a robust power supply for a preamp. Plenty of wonderful sounding tube preamps with low part counts and brilliantly designed circuits. Circuits with very short signal paths and low noise. Backert Labs comes to mind as one example.

So one can certainly find high quality preamp sections in an integrated amp. They can be found presently and one just needs to do due diligence when shopping. Also, there are some real sonic benefits to eliminating long ICs and connectors with a well designed Int amp. These shorter signal paths do have potential sonic benefits that offset some of the advantages that separates offer. Many integrated amps out there utilizing SOTA attenuation beyond an Alps pot 🙂.

Well thought out design including internal shielding and chassis vibration control can also help mitigate the advantages of separates. Simplicity does bring the opportunity for sonic gains.

Over the years I have heard integrated amps that are sonically superior to separates costing much more. I have also heard separates outperforming more  costly integrated amps. It comes down to the design implementation of the pieces in question, not simply the chassis count. Also, we listen to complete systems and the synergistic impact of the Int amp or separates also plays a role. It seems to me there are many considerations.

I have an MSB Discrete DAC with a Premier Power Base.  it has a built-in volume control, so a preamp is unnecessary.  However, at the urging of my local stereo dealer, he lent me an ARC LS28SE to try.  I felt that it really added so little benefit that I returned it.  However, when I moved up to an ARC REF 6, there was a marked improvement across the board. So does one "need" a preamp?  I didn't, but putting the REF 6 in the system really bettered the volume control in the DAC.  I think that it is a testament to the quality of MSB's volume control that one needs a 16K preamp to better it, but better it it does!