If your power amp has input level controls, as some vintage Crown amps did, I would suggest attenuating them to allow your analog preamp volume control to operate with normal listening at the noon mark or a bit above, and your DAC or source unattenuated (-0dB). That way you avoid the loss of resolution from the source, and the nasties that most VC pots exhibit near full attenuation…at least try that and judge for yourself.
Digital gain vs analog gain
Is there a rule of thumb that guides the balance between digital input level, analog pre-amp input level and analog amp attenuation for reach your desired listening volume?