You mentioned the EMM DAC2X, tho I don’t have the DAC2X I have the EMM DAC6e whose close brother the DAC8 was used for mastering most of the early SACDs. It’s noisier in my system than the DS (for multiple DS releases now.) As Elk mentioned some noise is inherent in any SDM approach and more in a single bit SDM approach. If the noise is white it doesn’t get in the way of details, if it’s colored it does much more readily obscure details. The best way of lowering the noise from the DS is to have the DS’s volume up pretty high, e.g. 80-100 when listening to the loudest material you’d normally listen to. At that level, if the system is fairly well level matched to that (which often required a preamp, but not always) there shouldn’t be noticeable noise at the listening position, of if there is any when the system is idle it’s gone when any music is playing. That’s why the noise that’s there isn’t a problem when mastering, they are very adept at optimizing S/N for each step of the process.
Still lowering noise matters and every time I lower noise in the FPGA code we all hear the difference, even tho those changes are not measurable by myself, John Atkinson, etc.
The TSS lowers noise in as many ways as I can think of. Here are some, but not all: By doubling the number of digital switches the noise is lowered by 3dB, the TSS uses more expensive digital switches which have a lower noise floor, the power supplies for the analog (and the whole unit in fact) are much quieter over a broader frequency range than those in the DS, the isolation of the digital from the analog cuts down on both conducted noise and RFI from the digital processes, but it also keeps the ugly step brothers away from the analog: the display, things like USB and Ethernet… There are also some slight architectural changes in the analog section that should allow more noise tweaking in the digital signal processing. Since I don’t have a running system I don’t know how much I’ll be able to get out of that in the first release, but the either in the first or second software release I’ll be able to get some noise out that wasn’t possible to squeeze out in the DS or DS Jr.
Ethernet isn’t a panacea, the higher the frequency of any digital process the more noise but no one want’s to use 10MB Ethernet these days. Ethernet is great for mastering houses, studios, etc. But it’s not yet ready for general use in the consumer audio world: there’s no standard for audio transmission protocols so you need devices on both ends of the ethernet link that talk the same language. In a pro environment you can have all parties using the same hardware (at some level) and side step the standardization issues. Right now with bridge like devices the standard is using a computer on each end to transfer files (or some other computer to computer speak.) This isn’t the best for audio: having a computer at each end of the wire… Note also that Ethernet by design has to pass noise that exists in the same frequency range as the signal. There’s common mode and differential mode noise rejection in the Ethernet connectors as well as down stream, but it’s not the case that Ethernet is fundamentally better isolated than other interfaces.
I have trouble with the term voicing: In the DS, DS Jr and TSS I simply strive to do the least damage to the audio. I don’t pay any attention to tailoring the sound, I just work towards the technically best processing (both in hardware and software) that I can do and I know that that does the least damage to the audio. The only way to make a DAC work well in all systems is to use the interfaces that are there as faithfully as possible. As a not so obvious example, in each release of the software I attempt to lower the ultrasonic noise as much as possible: since not all audio related hardware is designed with ultrasonic noise in mind some of it will react badly to too much ultrasonic noise. Whether a given preamp will negatively affect the audio because of the ultrasonic noise more than a given amp isn’t obvious. But in general the wider bandwidth the preamp, the amps, the speakers handle linearly the better: I like my speakers that are +/- 3dB to 50k, the amps to 200k, the preamp to 100kHz. Just 20k at each of these steps is not near good enough for audio unless the input is filtered to 20k…
You mention a compromise in harmonic integrity: there’s no such compromise in the DS or the DS Jr, pre amp or no preamp. Or at least there’s no compromise bigger than any other audio component that doesn’t have infinite linear bandwidth. The real issues with needing a preamp are filtering ultrasonic noise that your amps or speakers react badly too, allowing shorter interconnects if the interconnect capacitance is noticeably higher than “standard” consumer audio interconnects, and most importantly helping with signal to noise issues if your amps (and speakers) aren’t designed to give you the sound levels you want with an input sensitivity that matches the DAC’s output voltage levels. So (ignoring bandwidth issues) if your amps deliver exactly the power that your speakers need to be as loud as you need when driven by the voltage that the DAC delivers you won’t need a preamp and there will be no compromises.
As has been mentioned I’ve mentioned my home system on several threads
I have JMLab (Focal) Nova Utopia Be speakers with the inverted beryllium domes, silver speaker wire (and until recently silver interconnects), sand amps, but still there’s no exaggerated hiss, etc. I’ve had many complements that my system sounds like Maggies but with better base, or it sounds like it has tubes, or “is that sub on?”, “where is the center speaker?”, etc. It’s not perfect by any means and these days my ears are further from perfect but I still double check with my LCD-3’s and with my wife’s or daughter’s ears.