Core Machine (Operating system/System info/Roon build number)
Nucleus+ connected via a SOtM network switch to Naim ND555/Uniticore and router, all hardwired using ethernet cables
Description Of Issue
My ethernet cables are directional so should be oriented between source and device. So when I use ROON/Nucleus+ rather than the Naim app to direct streaming is the Nucleus effectively a source or is it simply controlling a signal going from the Uniticore to the ND555 so cable direction is not important?
Nucleus is the source in your chain. Only you can decide which way is better.
From the 802.3 standard (IEEE Std 802.3-2012, sec 3, p. 180):
The aggregate data rate of 1000 Mb/s is achieved by transmission at a data rate of 250 Mb/s over each wire pair, as shown in Figure 40–2. The use of hybrids and cancellers enables full duplex transmission by allowing symbols to be transmitted and received on the same wire pairs at the same time. Baseband signaling with a modulation rate of 125 MBd is used on each of the wire pairs. The transmitted symbols are selected from a four-dimensional 5-level symbol constellation.
I guess ALL Ethernet cables are Directional, at the device connection there is a Transmit Pair which sends data in one direction (OUT), and a Receive Pair which has had data sent in the other direction (IN).
And at the other end the roles of each specific pair are reversed… and OUT from the sender becomes IN to the receiver.
However, if you read the extract from the IEEE standard that Ged quotes, it states that full duplex is achieved on the same wire pairs.
I confess I’m intrigued by the statement that reads:
The transmitted symbols are selected from a four-dimensional 5-level symbol constellation.
It’s all getting too timey-wimey for my old brain…
Directionality will be determined by how/where any shielding is terminated.
Often (but not always) cables that are deemed directional are often shielded but with the shield only connected at one end. The cable designer then determines directionality based on where he thinks that earth is best connected.
“Where he thinks that earth is best connected”? - is this a gut feel according to the individual designer, or is there real objective science behind the decision?
Objectivity is rare in HiFi cable design and marketing. I have tried to use my practical knowledge to figure stuff out and I know of only one place in my business (telephony switching and IP) where a shield is only connected at one end. So it can have some credence but it doesn’t explain directionality where there is no shield or that shield is clearly connected at both ends.
I have my Chord Sarum and Anthem Streaming cables wired in the direction of source -> streamer (NDS), so ‘from’ Roon device ‘to’ switch and then ‘from’ switch ‘to’ streamer, based on the fact that during playback the data flow will be this direction, with only ACK frames being returned.
This question wasn’t whether Streaming cables make a difference, but whether a Roon device should be considered as a source.
What did the SotM switch do for the SQ?
The signal always goes through the Roon Core.
Streaming content or local off-Core storage, will firstly go into the Roon Core from the router or local storage (such as the Uniti Core) and then out from the Roon Core to the various output devices, being the ND555 (if used as an Output).
So the Nucleus is both the destination of data from the router and local storage and the source of data for the ND555 (if used as an Output).
Ethernet is full duplex, so packets are being sent in both directions at once. The physical Ethernet signal is AC because it is mediated by transformers. I don’t know what it means to talk about directionality in relation to a full duplex AC signal.
The SOtM replaced a CISCO Catalyst 2960-C switch which in turn replaced a Netgear Pro unit. All 8 switch units. The CISCO made a massive improvement to the SQ vs the Netgear which encouraged me to upgrade from MEI ethernet cables to Wireworld Starlight Cat 8 cables, which are directional. A further albeit subtle improvement . The SOtM including internal clock is better again particularly in terms of dynamics and timbre but given its higher cost bang for buck not as good as the CISCO but clearly worthwhile to my ears in my set up. Overall still marginally prefer the sound when controlling from the Naim app vs through ROON app though have no idea why that should be so, pasing throughmore cables/devices perhaps.
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