Can I connect Roon Nucleus directly to DAC, thus avoiding a streamer?

What is value in adding a streamer to a Roon Nucleus. Seems connecting Nucleus directly to a TT2 Chord DAC and then to Macintosh Amp and then to B&W 804 D3 speakers is all that’s needed. What’s the value in having a separate player??

I plan to connect nucleus to dac using usb to get max bandwidth.

No advantage that I am aware of. Someone might say SQ, but I doubt that.

Sure you can set it up that way. The value in using ethernet to separate the core and the endpoint is, for some people, an increase in Sound Quality. Now, whether or not you hear any benefit is on an individual case basis.

Some think that the signal that comes to the DAC via the Computer PC USB connection is very noisy electrically and can degrade the audio. Also, that boutique streamers ’ USB implementation is better and less electrically noisy, like the UltraRendu.

Personally, I prefer DACs that can be connected directly via Ethernet, eliminates all this discussion.

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How can u connect Ethernet directly to a dac? Do u mean usb?

No, I mean DACs which have an Ethernet input as part of the DAC.

Honestly I facepalm every time I hear this nonsense about USB degrading the audio. It’s a gross misunderstanding of the USB specification and how digital audio works. In fact, ethernet would suffer from similar issues. For context, I’m a software engineer w/ around 8 years exp in high performance and low latency computing so I’m not just making stuff up here… I’m intricately familiar with what’s involved.

With USB, a form of error correction called CRC (cyclic redundancy check) is used to detect corrupt packets. For data, a 16 bit error correction is used. With USB (assuming a typical digital PCM output), that means that if, for some reason, electrical noise or an act of god (eg; cosmic radiation) interferes with the transmission of a packet, it will be dropped (unless there’s some kind of retransmission logic). You won’t hear a somehow “lower fidelity” audio stream. It will just cut out. If you continue to have bad packet loss (eg; a faulty connection, too long a run of wire, etc.) you will hear constant stuttering and dropouts. Typically USB DACs won’t buffer internally because they want to output audio in the lowest latency possible. So they’ll just cut off like that.

With ethernet, there are additional layers of checksums (both at the link level and at the transport level) but the behavior can still be the same. Either (if using UDP) the corrupted (or missing) packet is dropped or it’s retransmitted (which in practice means a dropout unless you have a sufficient buffer… and then you’ve eliminated the ability to play audio in low latency eg; for playing movies or games).

Thing is, ethernet can absolutely be noisy! For context, even on a trading system processing 10gb/sec of data on absolute top of the line networking hardware with custom ASICs for error correction you’d still encounter a corrupt packet every few weeks. On a home network with consumer grade gear? 100x that. Where ethernet shines is long runs of cable. And obviously host to host communication.

What about jitter/errors in the clock domain? Excellent question. So, while over ethernet you can send over data in large chunks which are then played using the output device’s clock via USB audio is typically sent as PCM which is dependent on having a stable clock. The solution? Almost every modern “audiophile grade” DAC reclocks the data using its own internal clock. So if you’re using a poorly designed USB DAC you could definitely have a degradation in sound quality this way. If you’re using a streamer/USB DAC with its own internal clock then no it’s not possible.

The biggest gains you’ll get from a streamer are if it has a better internal DAC. Conversion to the analog domain is actually capable of introducing distortion even in the best designed systems. Well, and the convenience aspects that streamers offer.

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Some people just like gear.

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I have a Roon Nucleus “streamer”. It works great. I stream Tidal and Qubuz almost all day every day. My Oppo 203 is connected by ethernet and HDMI. I can’t tell any difference. I have 2 different headphone DACs connected by ethernet or WIFI to RPi4, then USB to DAC. I can’t tell any difference. They all sound great with no audible noise.

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I guess I could have stopped reading there… (I didn’t - I have read the whole post)…

Everything you say is true, but doesn’t address the actual mechanisms that may (insert preferred caveat here) affect sound quality. Anything physically wired to the box that generates the analogue output may couple electrical noise to the power supply or ground plane, which certainly can affect sound quality. Even differences in internal processing can have an effect.

How likely is it that you can hear these effects? Well - I can’t. But I can’t deny that these are plausible reasons why some people in some circumstances can hear them. I suspect some people are kidding themselves too, but that’s a different matter…

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Value is a very personal measurement. But by far the simplest way to make Roon work is a core and USB (or sound card).

I use a Raspberry pi connected with usb to my Dac, improved sound quality from the previous Bluesound streamer

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The Nuclues is in fact the same as an Intel Nuc with Roon Rock, I wouldn’t connect it directly to a dac, it is possible but I prefer a dedicated streamer such as a Lumin for example

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I tried plugging my DAC into the USB port on the back of my QNAP NAS (Roon core) and it worked but I was always disappointed with the quality.

So I switched to a network streamer into the DAC the sound quality was much improved.

Not a Nucleus but similar concept.

Edit: I didn’t go crazy on the streamer neither, just an Allo USB Bridge.

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Thank you Alfredo great description on how it really works !!

I like the “facepalm” tooo

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I’ve been looking at options for headphone listening from a position not far from my Nucleus.

I had been considering various streamer/dac/headamp combinations at various pricepoints (intending to create an endpoint via ethernet to the same switch as the Nucleus), but now reading this thread it dawns on me that I could just plug a Dragonfly directly into the back of the Nucleus and listen directly.

Not sure why this didn’t occur to me sooner. Does anyone have any experience with this?

May i ask why? I’m genuinely curious. I have my NUC usb to an OPPO 205 DAC. What would be the difference?

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One reason may be that ethernet is bidirectional (usb is not in this case), allowing feedback to the core as to signal path and volume via RAAT.

Honestly, I facepalm every time I hear nonsense from “engineers” about how USB and digital audio is supposed to work. I have 40 years experience in computers and networking.

You are forgetting about electrical noise…and all that goes along with it. I am not going to rehash this again as it has hashed and rehashed on this forum a zillion times…

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Hi this same debate is happening on the Innuos forum. I have an innuos zenith running Roon core and it plugs straight into my high-end DAC. ( I use high-end simply to say I spent what was for me a ton of money. ) I have a modest Analysis plus usb cable. The bog standard Ethernet cable simply plugs into the Innuos. It’s a single zone in a treated, dedicated listening room. The sound is the best I’ve ever had, so happy with it.

Now a kindly Roon brother suggests that I may get better SQ by adding an eg Sonore UltraRendu between the Innuos and the DAC. I struggle to understand what is actually happening, but somehow the ultraRendu is supposed to provide a better USB signal (read that as I should hear better SQ) to my DAC. Meaning the ultraRendu has some electronic componentry that the Innuos does not have. The lad down the pub, Darko, says the same thing but doesn’t explain why.

As the ultraRendu is not expensive, I am going to give it a try when I’m not busy, round Xmas time. But imagine trying to blind test that, it’s a pain, and anything apart from a blind test will leave me exposed to expectations-purchase bias. Luckily I am yet to succumb to buying an audiophile Ethernet cable haha

Cheers
H

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@Alfredo_Luque, while there is a lot of nonsense around USB degrading the audio, there are some that are not talking about the bits… I strongly believe that these issues should be resolved by the analog component manufacturers, but we have what we have…

If retransmission (meaning feedback coming back up the wire could fix the audio), then you’d hear breakage in in the signal, not fidelity loss. See my post above.

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