Not in the digital domain, where bits can be 100% recovered after transmission, should there be any significant [analog] noise affecting the line.
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thanks! This is what i thought also
I agree that most digital data transfers have various protocols and methods that insure digital data arrives in a 100% digitally correct manor… However, a DAC is a Digital to Analogue Converter… Therefore Analogue Noise may Ingress through various routes, including an electrical conductor digital cable, Into the Analogue Stage of the Converter which would pass along this noise to a PreAmplifier and/or Amplifier regardless of 100% digitally correct data…
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But since DACs have internal buffers/shift registers etc., they consume “internal” bits at the D/A stage rather than those coming directly from the input, and the 'quality" of those bits is entirely under its control (e.g. power rails, switching speed etc.) To put it differently, DACs can - and should - “purify”/“re-clock”/“condition” their own bits. The only time when this matters is at D/A time, so it’s best done in the DAC.
Well designed DACs deal with any potential noise ingress entering them via cabled connections. If your DAC suffers from this type of noise ingress, buy a different one.
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Seems you guys are missing my point… EMI and RFI may strike anywhere and along any path… My system is just fine… Thank you very much…
You keep talking about the digital side of the DAC while I am talking about the other side of the DAC… The Analogue side… Unless your DAC sits in a Faraday Cage, there are EMI and/or RFI issues to consider with…
Sure, and if you have a competently designed DAC, all of those issues have been taken care of by engineers who know an awful lot more about these subjects than you.
Just exactly what level of expertise do you have in the field of “EMI and/or RFI”, or are you just regurgitating BS spread by manufacturers of Snake-Oil products and the popular audiophile media channels?
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Fortyish years of hardware and software R&D… Signals and Image processing… Everything from handheld hardened to the kinds of things you would find at the Bracknell Data Center… We used to use static generating wands for testing some devices… Have also used in circuit emulators, oscilloscopes, etc… HP, TI, Intel, Biomation, Halcyon, etc… It might be interesting to see how well various DACs stand up to the wand… Or a neighbor with a shortwave kit with a nice beam antenna pointed your way…
And you?
Cool, so if you understand this stuff to the depth that you say, why are you worrying about the vanishingly low levels of noise
that may find their way into the analogue stage of a DAC from the digital input side or the power supply?
Such noise has been proven again and again to be significantly below the threshold of audibility on any competent DAC.
Well-designed modern DACs achieve measured SINAD of >120dB.
A quiet room has a background noise level of ~30dBA. To shift the noise over the audibility threshold, the signal would need to be at a levelwhere your ears would bleed.
Sure, how many of us have a DAC in direct line of sight to a high power, short wave radio transmitter? You’re citing impossibly extreme cases to justify your even more unlikely arguments.
It’s like me screaming that a CD player has a harmful laser (Class 1) in it, because I’ve seen a 300W CO2 laser (Class 4) burn a hole through a brick…
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As I have said many times above… All (analogue) noise is additive… So your “vanishing low levels of noise” in a signal chain adds up to something that becomes fatiguing… Maybe you don’t recognize it as noise, but it is there grating on your ear/brain… Of course, some types of noise may seem pleasing to some and others not so much… As for SINAD I am not a fanboy… Even Amirm suggests that you not take is too seriously… As for the threshold of audibility, their is a lot of room for understanding how small signals mix and interact with the environment and the human body… My own experience in the US is that there exists many emitters of EMI and RFI in the environment… The short wave transmitter is only one of many… And my hands on experience with lasers leads me to believe the issues with EMI are about firing up the laser, where signal lines glitches from a capacitor discharge to get the laser up and running…
I am still waiting to hear of your vast hands on experience…
The curious mind is a wonderful thing, but it doesn’t always know when to leave well enough alone.
In general, adding any unnecessary electronics to a signal chain is more likely to degrade the signal than improve it.
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That is strange! You got it the other way round. 
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You’re hypothesising again. If you have all this real world experience, give me some numbers. At what level below the signal does the noise become audible? Offer up some evidence. So far, all you’ve done is repeat the same arguments.
Forty years of experience to come up with that statement?
There are hundreds of sources of emissions all around us, all day, every day.
How many of those are significant enough to affect the audio equipment inside your home, though? Surely with all of your experience, you’ll have an idea of the relationship between radiated power in a particular frequency band, it’s distance from a susceptible device and the level of audible noise it can produce in said susceptible device? Put some numbers on the table, otherwise you’re just testiculating…
If EMI and RFI are so bad in a domestic situation that it grates on your ear/brain via your audio chain, why do I have no issues with very sensitive electronic devices in harsh industrial environments? Switching of high voltage/high power loads (MegaWatts), high levels of harmonics created by PWM VFDs, massive solar PV arrays with their DC/AC inverters, micro-wave data links, radio telemetry transmitters etc.etc.