Do Streamer only devices really impact sound quality?

Individuals use usb because it has best SQ vs other inputs/outputs available to them. I've observed many trying coax, AES/EBU, I2S inputs on dac, finding them inferior and returning to usb.

I don't know that the channel itself necessarily makes that much difference, to my ears. What makes a SQ difference, to me, is the various DSP options I can get (or cannot get) via one channel or another.  I need a USB connection to a Macintosh computer in order to run BAACH4Mac (a spatial audio processor). I need a USB connection to a Mac, or to a dedicated music server (with an ultraRendu in the middle), to run HQPlayer (which offers many filtering and upsampling options).  If I want multi-room playback, I cannot run either of those processes, so in that case I use ethernet (or, in the past, coax or RCA analog).  If I want to play TV sound through my HiFi, I need Toslink (because my system does not have a complete HDMI ARC path from HiFi to TV and back).

IOW, functional requirements  (as well as SQ) dictate the choice of streaming signal path, for me.  I've had at least 4 different streaming pathways in my system. These include the Bluesound Node 2i (which FWIW has one of the worst ASR measurements for a device of its kind) and also a Matrix Element X (which FWIW has one of the best ASR measurements for a device of its kind).  I haven't noticed enough SQ difference among those paths, per se, to override the functional differences.  And without going to a ~$30K T+A streamer/DAC (one  that supports  the NAA protocol), I doubt any of them delivers enough SQ improvement to justify doing without HQ Player (or BAACH4Mac).  Which I'd like to do, just to simplify the chain. But I'm skeptical that a change of streamers alone can make my soundstage sound about 50% wider, as BACCH4Mac can for some content. 

@tk21 Good points.

Another thing that needs to be pointed out. The optimal mode of transmission depends a lot on the quality of the rendering in streamer. Some streamers take great pains in optimizing usb in use of high quality clocks and power supplies on dedicated circuit boards, ,others take usb directly off relatively noisy motherboards.

Point is not to generalize about inputs/outputs, each case is different. Research both dac and streamer for optimized ports and purchase compatible components. USB has some theoretical disadvantages, but implementation has been continually improving, blathering objective statements only further confuses people.

Point is not to generalize about inputs/outputs, each case is different...blathering objective statements only further confuses people.

@sns Oh, you mean blathering like this?

USB inputs are optimized in many dacs, preferred by many.

Really? Where’s your proof? Didn’t think so. Of the hundreds of posts I’ve read on the subject yours is the ONLY one I recall where USB was preferred to i2S with the exception of Holo DAC owners where it’s well known that those DACs are optimized for USB, which seems to be much more the exception than the rule. By contrast, I’ve read many, many posts where i2S and/or AES/EBU were superior to USB or SPDIF. Maybe your DAC sucks and can’t realize the benefit of an i2S connection, or maybe you used an HDMI cable that was too long — I dunno, but I think you’re in the distinct minority on this unless you can quote others preferring USB over i2S besides, apparently, people with your specific DAC (or Holo, obviously) because I sure ain’t seen them but can cite many (including me) who’ve found i2S to be vastly superior to USB. Your move chief.

I have (and love) a BlueSound Node 130. It has a great interface, and is easy and intuitive to use. For a while I thought about upgrading, but instead went with a DDC (Denafrips Iris DDC). It isolates the signal galvanically and optically, so the signal gets sent to the DAC (Denafrips Pontus II) cleanly.....I've done a review elsewhere here.

I'll keep what I have now as I'm completely happy with it, but at some point will want to compare the quality of that pair with higher end streamer. Price will be hard to beat, $600 for the Node 130 and $500 for the Iris DDC; damn good pair for $1,100