DAC-Preamp having these specifications?

So the DAC3 uses method 2

This (linked) is where I believe the volume is controlled in the digital domain before d/a conversion. The other so called "hybrid" part is just an analogue gain adjusting (0db -10db -20db) on the output buffer for the maximum level volts obtainable if the digital volume in the ESS chip is full up.

https://ibb.co/h4MbD9

Cheers George

I have sent a request to benchmark about this topic.

So did I yesterday, nothing back yet.

Cheers George

BTW: Good on Benchmark for recognizing "bit stripping" even in the ESS-ES9028PRO converter and implementing an analog user changeable gain bock setting like Wadia and ML did. Bricasti did too in the M1 but you change theirs differently. 
https://ibb.co/d69hD9


Cheers George

 

Hybrid Gain Control system

Yes that "hybrid" word says to me half digital, half analog. The the gain setting (0--10,-20db) is done in the analog and the volume is done by the ess in the digital.

The output impedance isn’t uniform as a function of the different passive attenuator pads:
Attenuator: Output Impedance
0 dB 60 Ohm
-10 dB 425 Ohm
-20 dB 135 Ohm

The output impedance isn't uniform as a product of the gain setting, not the volume control.
That’s because the gain is most probably changed via different feed back resistors of the output buffer which will effect it’s output impedance, not to worry though, they are all low enough for your active ATC speakers.
Just use good quality low capacitance interconnects to them say ( less than <100pF "picofarad" per foot) ask the manufacturer. Keep them short as possible 2-3mt will be fine

Cheers George

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

celander
@georgehifi My ATC active monitors have a 10-kOhm input impedance, so I need something having an output impedance lower than 1-kOhm.

Yes generally as 1:10 rule I use it, "if" your interconnects are low capacitance and around 1mt long, source to amp.

But your going from dac to speakers with these interconnects, probably around 4mts, so I would err on the side of caution and have the dac’s output impedance 100 or 200ohms.

Cheers George

If a DAC-preamp manufacturer uses only an analog volume pot, then can one assume the digital domain is set for 100% output, thereby ensuring no bit-stripping arises? I’m thinking here of the Benchmark DAC3.

Yes, no "bit stripping" if the volume is done in the analogue domain after the d to a converter. But I haven't seen this done since the old days, maybe the Dac3 is I'll look to see if it is.

Cheers George

celander OP
  DAC-Preamp having these specifications?

Look for one that's direct coupled on it's output buffer, and I would go <100ohms output impedance. And also has these features for the best quality.
Go for one that has settable max analogue gain output, so you can use it’s digital volume control in the top 25% part of it’s range.
This way your sure of not "Bit Stripping". Just like Wadia and Mark Levinson do on their Flagship models.
Today I know M1 Bricasti has it, there must be others as well, these are the ones I would go with as they know about "bit stripping" that's why it’s introduced. As the Wadia attached shows.

https://ibb.co/d69hD9

Cheers George