whether I should utilize the volume control on my Gustard R26 DAC or via one of my (pre)amps like Freya+ and Holo Bliss.
What would be the disadvantages/advantages of digital attenuation vs a passive (or buffered) preamp?
Gustard first 30dB of volume attenuation is analog, but any attenuation more than -30dB is digital which is achieved by shortening the word length of each sample (throwing away music data.) With very high (>-50dB) digital attenuation it will sound gritty. So if you normally listen at -30 or louder then you can use Gustard alone with no penalty. You can still turn it down lower for background music etc, but it will be throwing away some data bits to affect the digital volume attenuation. This is not usually audible until another -20-30dB of digital attenuation. At that point your total attenuation would be -60dB which is a lot, so you wouldn't listen that low anyway.
But you may still prefer the sound of the preamps in the signal path anyway. Every component changes the sound in some way, and active preamps are often essential to the musicality of the system. The preamps may have better remote control, or better bass slam, or smoother treble, etc. It's a personal choice depending on your musical taste, hearing range, and synergy with your other stereo equipment.
At first you will probably like the DAC>amp, as it may sound "more detailed" but after your brain adjusts to the DAC alone you will hear the flaws and can more prudently compare the pros and cons of all the options if you give it time.
