Do not buy the DAC if you want to use as a volume control. Get the DAC3B (no volume control) and buy the LA4 preamp (or HPA4). The LA4 will make the DAC sound better. That seems weird to add more signal path for cleaner sound but it will work like that with this ultra clean preamp.
I sold a $7.5K DAC so that I can buy a 2nd LA4 preamp for my new Livingroom system. If you want a clean sound the LA4 will deliver. The DAC3 with volume is not great at low volume.
My office system is LA4 and 2 AHB2's. I also have a DAC3B but I have that on my tube headphone amp. I use a Musetec 005 DAC with the LA4 + AHB2. I have a second Musetec 005 DAC that I will pair with my second LA4 preamp for my new Livingroom system. I am sold on that combo.
I do like the all Benchmark stack DAC3B | LA4 | AHB2, but the very smooth Musetec 005 is a nice touch over the slightly brighter DAC3B.