Should I adjust my NAD M51 DAC volume north of 0 dB with this setup?

I agree they blew it by not putting a volume control on such a killer DAC. I’d pay extra for it and my dream would be one set of line level RCA inputs.  I could then run my phono pre to it and not need a main preamp.  

I also have a c-j preamp... its a Classic 2 SE and it like most c-js has high gain. I would often leave the volume around 9 oclock on the pre and set the M51 to -20 or -10 so i could employ the remote volume on the DAC and not go past 0dB. Always sounds great . I normally hate digital volume, its why I traded my McCormack RLD 1 for the Classic, but the NAD digital volume is one of the best I’ve ever used. It is super smooth and the is no difference in quality at -20 or 0., its a great volume control. The only thing I dont like about that DAC is its lack of a front panel volume, serious omission on such a great DAC. They blew it on that one and would have sold a lot more if it was more like the preamp/dac they pitched it as .

I have an M51 in one of my systems and it is a great DAC IMO.

I set it at -20db or so (I do this also with another DAC in my big rig.) Both DACs claim no loss of data at that setting.

For me, it is about who provides the gain and how much. It sounds better to me to set the DAC at a lower volume and up the preamp volume to get to the desired listening level. My preamps are both CJ (ET3se and ET5) and are pretty quiet up to about 85 vol setting, which is way louder than I want even with the DACs set to -20.

I've experimented with different settings for the DACs and the pres. I've even run the DACs down to the equivalent -50 on the M51. I don't usually run the DACs down this low, given my typical listening habits...but of course I had a lot of OCD fun playing with the various knobs and dials.

I've heard recos to have the gain from the DAC at 0  and use lower volume settings on the pres...less noise I'm told. But on my system, this sounds unnecessarily thin and bright, tho' very dynamic. With the DACs dialed down and the preamps up, it sounds more coherent and organic to me with no loss (that I can tell) of clarity, bass impact, etc.

I've also tried the DACs as digital preamps without the CJs in the system. Very dynamic, but it doesn't sound as coherent and organic as with the pres in the systems.

Of course, YMMV.

Thank you oddiofyl!

I have a M51, great DAC...   I usually set mine at -1 to -3 dB going into my preamp as a source .  There is supposedly no truncation of data ubtil below -66 dB so experiment . You might find that -10 is a better match .  I personally dont think that unit sounds better as a preamp vs. a source component but it may in a different system so it doesnt hurt to try it that way as well.