STREAMER - WHERE DO I GO FROM HERE?

@jrareform 

As the British day, “don’t be daft.”. But let me explain the nuance a little more explicitly so you can follow:  yes, noise is the only difference.  no, SNR doesn’t capture every element of noise.  yes it captures a lot (including power supply noise that is not filtered). That’s it.  See, it really wasn’t very complicated.  So go pick a silly fight on the internet with someone else.

@mdalton wrote that @patrickalston said “SNR is one of the least relevant factors when comparing streamers in revealing systems.”

RESPONSE:  <sigh> Yes, I did say that and explained why specifically as it relates to USB-centric streamers connected to asynchronous DACs using the USB connection. What I said is true because USB transmits data packets (let’s call them 1s and 0s), not an analog waveform.  There is no analog signal whose amplitude can be compared to noise.  Therefore, a streamer’s analog‑domain SNR spec has no bearing on what the DAC receives.

Asynchronous USB breaks timing dependency. The DAC’s internal master clock controls the timing—not the streamers.  So.  the streamer’s SNR, jitter spec, or analog noise floor cannot influence timing accuracy. The DAC sets the system’s SNR.  The REX 3’s analog output stage, power supply, clocking, and noise‑shaping architecture determine noise floor, dynamic range, distortion, and (drum roll) final SNR.  Therefore, the streamer contributes zero to the analog SNR of the system.

@mdalton also wrote “ . . .if your DAC is noisy . . . nothing you can do on the streamer side to remove that noise.” 

RESPONSE – We agree.  I’ve already said that “. . . the streamer contributes zero to the analog SNR of the system.” Understand that the streamer’s noise never makes it to the asynchronous DAC connected through USB (I know I keep repeating that, but I want to be clear about what I’m talking about (i.e., My DAC and others like it.) I don’t know about AES,coax, or whatever else--I didn’t read about that---hmmm, perhaps I will.)

@mdalton  wrote “. . . I think that’s the point @helomech was making.” 

RESPONSE:  It’s one of the great mysteries of this thread.  He never explained his assertion that “there is absolutely no way he [i.e., me] is going to hear differences in streamer quality because [I] have an all-tube system.  So, we may never know the details of his position.  I suggested that perhaps his system is not revealing enough to differentiate between streamers, but he’s likely never listened to my system let alone a unicorn DAC like the Rex 3.  I dunno.  I just wish that when people say something that they would explain why they believe what they do.

You also wrote, “a system’s SNR can be dragged down by a noisy streamer, a dac, an amp or a preamp.  It just depends where the noise is coming from.  For example, if the power supply of a streamer leaks noise, and your DAC doesn’t filter that noise, it can manifest in the output stage of the DAC (which is in the analog realm). And that has nothing at all to do with the data packets.”  

RESPONSE – Ok, now you’ve expanded the discussion to include the amp and preamp. I concede that the amp (or in my case, amps) and preamp can impact the noise level heard through the speakers—particularly electrostatics like mine, but that's outside of this thread's scope.  I'm happy to have that discussion if only to learn.  

Regarding the potential for a streamer’s ability to impact the SNR of an asynchronous DAC connected using USB, that’s not true based on what I discuss above (only 1s and 0s are passed to the DAC).

I don’t know what else to say beyond you’ve really challenged me even though your position is flawed <smile>.  I’ve learned much about DACs, connections between DACs and streamers, and how the right choices maximize a system’s potential.  I appreciate your and everyone else’s responses. 

@jrareform asked @mdalton “so you’re saying that the issues regarding the power supply and other distortions from the streamer can be boiled down to SNR?  What about clocking issues?”

RESPONSE – You hit the nail on the head (well, one of several heads)

 @jrareform wrote “test two or three competent streamers in your system and let us know your thoughts!”

RESPONSE – I will. 

@2psyop  – Thank you for your report on the RS130.  I  love that screen.

To the OP:  You’re just wrong about the potential impact of a streamer on SNR.  If you were right, streamers wouldn’t matter at all, and it would be fine to use your PC as your streamer.  I refer you, for about the 5th time, to actual measurements of this precise issue conducted by paul Miller.  He measured the SNR of an Audioquest Dragonfly using a PC as streamer: 94 db.  Then he measured the SNR of that same dac using a Volumio Rivo: 104 db.  So the pC added 10 db of noise.  No idea where you’re getting your ideas, but they’re just demonstrably incorrect. 

oh, and the pc was connected via usb (as was the Volumio).

Here’s the actual review:

Rivo review

There are numerous other examples, but the answer is the same.  Just  having a USB connection doesn’t eliminate all sources of noise from a streamer to a DAC.  Not sure why you’ve dug in on this indefensible point.  Really weird.