Just had a look at what Sterophile makes of the DAC30’s volume control, and it’s a bit vague, but to me point to it being in the digital domain not the analogue as that ES9028PRO d to a converter has volume option.
As they talk about extra resolution if you use it in the top part of it’s range. And benchmark give you the options of 0db or -10db or -20db gain attention structure in the analogue domain output buffer so then it can have the volume control it the top part of the range. (This wording "could" be the reason why some think it has a normal analog volume pot.)
Stereophile:
The DAC3 HGC has another feature that, while hardly sexy, addresses a common and underappreciated problem. Is your volume control usually set above or below the halfway point? In my experience, for most systems the answer is "below"—but most systems achieve their best noise performance in the top half of their volume range for both analog and digital volume controls (though for different reasons). Also, analog volume controls exhibit their best channel-matching in that range. The DAC3 offers pads for its balanced outputs—attenuators—that can be set, via internal jumpers, to 0, –10, or –20dB. Benchmark says that when they’re in use, the DAC3 retains its full signal/noise ratio of 128dB, A-weighted. If you’re paying for 24-bit DACs and hi-rez downloads, you’d best get your noise level down to where you can hear at least some of that extra resolution, and that’s harder than you might think
They do what Wadia did by the looks of it.
Quote from Wadia
We strongly recommend that you use your Wadia 521 Decoding Computer connected directly to your power amplifier. Even if you purchased your Wadia 521 Decoding Computer with the intention of connecting it to your preamplifier, we suggest that you try direct connection to your amplifier. Many listeners are surprised by the improvement in performance over even the most expensive preamplifiers.
Optimizing the Output Level Best performance is obtained when operating the Wadia Volume Control near the top of its range. If needed, the maximum output level of your Wadia 521 Decoding Computer can be adjusted to match the overall sensitivity of your system so that the critical listening will take place with the volume control operating in near the top of its range.
The maximum output level of the Wadia 521 Decoding Computer is adjustable by means of a set of internal switches. The Wadia 521 Decoding Computer is factory set to accommodate the most common range of system sensitivity. If you find that your typical volume level during critical listening is below 65 on the volume display, it will be advantageous to use a different setting. To change the output level, consult your dealer.
BTW the DAC30 has a lovely low 10ohm output impedance and will drive anything, just set the gain setting (0,-10, -20db) so you volume is up near full for very loud and you won’t run the risk of "bit stripping" "if" it in the digital domain.
Cheers George