Hah, of course I am only using these (incredibly expensive) specific cables because of some other thread on some other message board said that I should. But I can’t remember where.
Is there any science showing that STP causing audio noise is a known Ethernet issue, and it’s not specific to the Raspberry Pi?
I just got finished breaking down the entire hifi rig and because the installers are coming to put in new windows. Once I get it all put back together next week, I’ll A/B test some other cables. I have some UTP CAT6 and 7 here to try.
the best network cables for audio are f/ftp types.
Makfi, maybe a typo in your response but to be clear, the naming convention for twisted pair cables is x/xTP, where TP = twisted pair (4 pairs in current standard), and x = either U for unshielded, S for braided outer shielding, or F for foil shielding (can be outer or per pair). So an f/ftp cable would have an outer shield of foil, and each pair would also be individually shielded by foil. An s/ftp cable would have an outer braided shield and each twisted pair would have an individual foil shield. s/ftp and f/ftp are the only cable types used in the CAT 7 spec. They are also used in the CAT 8.2 spec but CAT 8/8.1 uses f/utp and u/ftp like CAT 6A. The only cables with truly unshielded are CAT 5/5e/6.
modems and routers are mostly two prong devices that carry a lot of ac on their chassis: just measure with a voltmeter connecting one probe to a metal part in your router (i.e usb input if it has one) and the other to the mains ground and you will see the amount of ac leakage. it is usually 1/2 of your mains voltage, 60v or 110v depending on where you live.
now, remember that the lan connection is galvanically decoupled using a transformer, but the shield establishes another connection and carries all the noise from one end of the cable to the other.
i do not think there are unshielded cat 7 cables but i might be wrong. check again with multimeter using the continuity function on the metal parts of the connectors.
Makfi, maybe a typo in your response but to be clear, the naming convention for twisted pair cables is x/xTP, where TP = twisted pair (4 pairs in current standard), and x = either U for unshielded, S for braided outer shielding, or F for foil shielding (can be outer or per pair). So an f/ftp cable would have an outer shield of foil, and each pair would also be individually shielded by foil. An s/ftp cable would have an outer braided shield and each twisted pair would have an individual foil shield. s/ftp and f/ftp are the only cable types used in the CAT 7 spec. They are also used in the CAT 8.2 spec but CAT 8/8.1 uses f/utp and u/ftp like CAT 6A. The only cables with truly unshielded are CAT 5/5e/6.
hi karl, you are right, I was not clear. what I meant was that the outer foil or braid is very beneficial in terms of reducing emi/rfi. but they also carry a lot of noise from your source. I had a custom-cable made using f/ftp using non-metal connectors.
The purpose of the shield whether it is S or F is to isolate the twisted pair from EMI and crosstalk noise. In a data center or commercial environment, a shielded cable is grounded through the patch panel in the telco closet which is connected through a series of grounding bars and cables to an earth ground near the electrical entrance to the building. Also, data center grade switches (and even many consumer grade like my Meraki) are grounded through the third plug on their power cable. If the patch panel, switches, and other network gear are not properly grounded, all you are doing is rendering the shielding ineffective because it now has no place to shunt the EMI and crosstalk noise it is supposed to intercept and prevent it from interfering with the signal on the TP wires. Worst case, it should be no different than UTP in terms of noise.
Agree 100%. Also, if you are not properly grounded, you are not only “rendering the shielding ineffective” but also carrying the ac leakage to your downstream component. that is you are even worse than an ordinary utp. this is based on my extensive listening tests and that is why unless you have data center grade networking equipment you should stick with f/ftp and s/ftp with the shield not connected.
Ok. I’m a baby when it comes to most of that stuff, so thanks for your patience.
As far as my networking equipment is concerned, there really isn’t any in the mix here, any more, other than the Sonos. And all it’s got is a power supply plugged into it with a three-prong power cord. So isn’t that grounded?
I would, for peace of mind, remove all cables except power cords, and with a multimeter set to measure ac volts, read the voltage between the chassis of each equipment and the mains ground. That’s including the modem, router and the switch. Properly grounded equipment should measure 0 volts ac.
remove all cables except power cords, and with a multimeter set to measure ac volts, read the voltage between the chassis of each equipment and the mains ground. That’s including the modem, router and the switch.
With apologies, since I might be too stupid to even be talking to about this, but I can't quite figure this out.
My modem, router and switch aren’t connected at all to any of this stuff, since I’m bridging with wifi.
The Sonos thing is made completely of plastic, I don’t think it comes apart, and I don’t think there’s any chassis inside it anyway.
When you say check for voltage between chassis of the equipment and mains ground – mains ground of what?
On the DAC, for example: Is the DAC chassis connected to the DAC mains ground? And I can’t really check for voltage between it and the Sonos. So I’m not sure what to check.
when you mentioned those expensive lan cables in post #61, I thought you were using them. it seems you are using wi-fi.
one probe of the voltmeter needs to go into the earth connection of your power outlet on your wall (or power strip) and the other goes to a metal part on your equipment, typically a screw that connects to the chassis. the rca connectors on your sonos will do.
when you mentioned those expensive lan cables in post #61, I thought you were using them. it seems you are using wi-fi.
Sorry I wasn't clear about that. I am using those cables: I have the my DAC and my NUC (Roon Core) connected to the Sonos Bridge using these cables.
The point is that the bridge is powered by an LPS with a DC filter, and the DAC and NUC are connected to them and nothing else. So the whole audio rack is isolated from the rest of the LAN without having to use a media converter.
I did try swapping out the CAT8 cables with CAT5E, 6, and 7 cables, and it’s hard to say if I could hear a difference. It’s tough to A/B test because the DAC and Roon both get mad when they lose their connection, so there’s a bunch of cursing and restarting in order to get the music going again. It certainly didn’t make the sound any worse, and on your advice I’m leaving the CAT6 UPT cables in there.
one probe of the voltmeter needs to go into the earth connection of your power outlet on your wall (or power strip) and the other goes to a metal part on your equipment, typically a screw that connects to the chassis. the rca connectors on your sonos will do.
The Sonos bridge is a chunk of plastic with no metal chassis nor screws, and no RCA connectors. Just 2 Ethernet jacks and a DC plug. Is it safe to try to get a reading through the ethernet jack?
Can anyone recommend a high quality switch, to which I will attach both my NAS drive and the Bridge-II? I will also use a passive galvanic isolator immediately upstream of the Bridge II.
As far as tweaks go, galvanic isolation can be effective and quite inexpensive. So what took me do long? Laziness or a disbelief in the benefits. I had some time over the holidays so I sourced two TP-Link MC200CM’s, an SC/SC Multimode optical cable, a TP-Link 10/100/1000 switch and a handful of CAT7 cables. You need the switch to make it work with the MC200CM. They only operate at 1000. The Bridge II works at 10 or 100 is my guess. First converter set to auto other set to force. Away I went, and a there was a difference. I heard details that were never evident before and I could swear there was more impact to the music. The tweak is staying. Although there is a rats nest of wires behind my equipment now.
The key with this kit, as you mentioned, is that you have to place the media converters upstream of a switch or the ethernet signal will not link up with the PS Audio Bridge. I added an iFi noise reducing power supply in lieu of the one that came with the switch for good measure: iFi Power Web Page