How to set up volume control on a DAC without a preamp

I use a PSAudio Airlens streamer to a PSAudio Directstream DAC to a Pass Labs XA-25 amp it sounds very good. I have no intention of adding a pre amp. You can get some very good deals on a used DSA Mrk I. I am going to add my OPPO 105 for CD to the mix but have not considered adding a turntable or researched the possibility of connecting one to the DAC if vinyl is in the equation for you. 

I would also be concerned driving an amp directly from a DAC. Roon has had a bug in past that caused the volume to ramp to 100%. Could be catastrophic under the wrong circumstances.

you can buy dac with Exellent volume control - APL hifi dac or Playback design dac.

Thank you for all the responses.  I have been looking at DAC's around 3k-4k.  They include some older Mojo Audio DAC's, Denafrips or Holo Audio.  I have also seen the new Musetec DAC that was just released.  The preamps I was want  is  the Spatial Audio Raven or having SMc Audio build me a TLC-2 to match my SMc DNA .5 modded amplifier.  None of these DAC's except the Musetec have  volume control and I won't be able to purchase the DAC and preamp at the same time.  I did however find some inexpensive ideas until I can get a preamp.  

I have used the ps audio dac with Ethernet for years and had Roon use the dac as an endpoint which I controlled the volume thru Roon. 
Since I wanted to use i2s, I am using the airlens in front of the dac and Roon connects to the airlens as an endpoint.

Since I got rid of all my vinyl and analog pieces when I was using dsd and MQA, I also got rid of my McIntosh preamp, after I tested the sq with and without the preamp, and my system sounded better without the preamp.