Help! Looking for a DAC with some unique ablities...

Good point @ericrhodes1.

You are certainly right with your concerns purely mathematically. HOWEVER, within a factor of 10 I would argue it is inaudible.

I have no idea what you are talking about, what 'factor of 10' are you talking about.

     There is also data reduction at the pre-amp volume control = signal attenuation/reduction.

Data reduction implies you are speaking of the digital domain, it certainly does not happen in analog.

     Next, the worst culprits are the speakers, particularly with respect to loss of.        resolution.

What's your metric for 'resolution'? If some thing is lost it must in in some quantifiable amount.

     Then there is Fletcher Munson to consider, so brain processing.

Maybe you could rephrase that in a complete thought, or at least a complete sentence.

    Accordingly, the digital volume control "argument" is a red herring.

No.

     Re dynamic range, that is the ratio of loudest to quietest. Whether it is  or 10,000:1,000 or 5,000:500, that is the same ratio, same range. Within reasonable limits, dynamic range is independent of volume.

Dynamic range is gated by the noise floor, whether of the electronics or the listening environment on the lower end and by the power and/or acoustical limits of the system on the upper end, so the dynamic range of the system as a whole is entirely dependent on volume. To achieve a playback dynamic range of 60dB requires a very quiet room (50 dBa or less) and a system peak output of 110dBa. To reach full symphonic levels of 120dBa requires 10X the power, and a speaker system capable of that level. 

For context a 2X8" tower speaker, pretty much regardless of manufacturer will have a maximum peak volume capability of around 112dBa.  Thats around 150W with a speaker sensitivityof 90dB @ 1W/1M. A 5" standmount, like a KEF LS50, 104dBa, with a sensitivity of 84dBa and 100W maximum power handling.

Working the other direction, a normal listening level of 85-90dBa might only require 1 watt of power, but the system will run into the listening room noise floor at 45-50dBa limiting the dynamic range to around 45dB. So dynamic range is quite dependent on volume. 

     Don't worry that much, just happy listening.

     The only time you might worry is with very quiet passages in very low res files. You *might* be able to hear a difference in the fade out of a pop song. For anything more real world, it is inaudible.

I'm afraid were going to have to disagree on you audibility claim. First, I'm way beyond 'worrying'. That said, truncated data is quite audible at normal listening levels between 80-90dBa. Second, your grasp on this topic is quite marginal.  

Thanks everyone for more good recommendations.

@oberoniaomnia  and @panzrwagn - great discussion, and this train of thought (is there any degridation due to digital volume control) is why when I was playing with the Blue dude settings I figured I needed to activate digital pass-through. Which in turn means volume couldn't be changed by the Node 2i. 

I've had plenty of discusssions with a good friend and fellow hifi enthusiast on the topic. Not that we came to much of a concrete conclusion.

Of course in the analog world companies take great efforts to make high quality attenuators - in fact Luxman makes a big deal of it with regards to my pre-amp. But just because it's a big deal in the analog world, I don't know if we can automatically say the same is for the digital world? i've no idea how that is done digitally. I would love to know more.

For myself, I think I've decided I'll find a quality DAC that I can afford to use instead of the Blue Dude dac. I think that will be a decent step forward for myself even if I do control the volume sent to it. Certainly I will be able to do easy side by side comparisons once I have a DAC. Including comparing the digital pass-through feature, and see how that effects things. 

E.

@panzrwagn factor 10. at 24 bit so ~16M steps, loud at level 10M, 10x less at level 1M.

The term "data" is not restricted to digital realm. A vinyl record contains data. Analog signal contains data/information. Whether volume control is carried out in digital or analog domain, it reduces the signal/data. Basic information theory.

Definition of resolution is the ability to transmit fine-scale information. So you could record the speaker and compare the recording to the original data stream. The difference in information content is the loss of resolution. With speakers being sonically the most variable component, variability = low fidelity (true to the source), it is clearly having the greatest effect on sound reproduction (except room maybe). As nothing good can be added, it can only loose information, and typically loss happens at the fine grained end, so loss of resolution. Really not rocket science.

Re noise floor, yes, correct mathematically, irrelevant on a practical normal listening level. You need to learn to figure out what is relevant, put things into perspective.

If your regular listening is at 85–90 dB, I pity your ears, or what's left of them.

@everhard Re using/bypassing digital/analog volume, you can easily check whether you can hear a difference by comparing the two volume controls. In a reasonable middle ground (say within 20–80% of digital volume), I would be surprised if you can hear anything.

In theory, you could even go from digital device with volume control straight to power amp (start at low volume) and check effect of preamp on sound. 

In theory, you could even go from digital device with volume control straight to power amp (start at low volume) and check effect of preamp on sound.

@oberoniaomnia One could, and I did. There was a difference. There was a massive difference actually. Folks who believe preamplifiers are obsolete and a DAC with a digital volume control is all that's needed are setting themselves up for disappointment.