Would I benefit from adding a switch?

tbh up to now I've been looking at all this talk of fitting chokes and using shielded cables with a certain element of scepticism. Any way I'll give it a go. So I've just got a selection of shielded lan cables from work and ordered a bunch of ferrites of varying sizes for mains leads, DC cables and LAN cables. Not costing much money so worth the experiment.

Hi FT,  no probs.

You say you have Cat6, but your profile says 6A,  so better ask twice & cut once = is it shielded ??

If shielded or at least shielded in the NAS to Switch section,  don't earth the switch.

-  as you rightly point out this gives a 2nd earth & can have a number of issues not least carrying a potential between different earths. 

FYI  the Netgear ProSafe switch's have cases that are connected to the port shrouds via small capacitors,  this blocks low Hz potentials but shunts HF (RFI) noise way to earth via a shielded cable - if fitted.    

Thanks for checking Mike.

It's Cat6a and the connectors are the shiny metal ones (for shielding, perhaps?), not the plastic ethernet connectors that the Cat5 cables have.

I'll unearth the switch then.

By the way, I've just looked up "ethernet Cat6a vs. Cat6" on google and it refers to an excellent web site definition.

Apparently, Cat6a rescues us from Alien crosstalk.  

Phew, I was really worried about that!  I'll sleep better at night, knowing that I'm protected.

Once again, may thanks for the advice.

Best regards, FT

I found that the more complete the protection from RFI, the greater the effect.

Adding ferrite beads to the Ethernet cables made a small but worthwhile improvement, adding them to the mains cable also made a small but worthwhile improvement, same with the analogue signal cables. 

When adding them to all the cables entering my audio system, the last chokes added made a greater difference than all the others had.

That's why SETI only use CAT5e

Whatever floats your boat, boys and girls! However, it was interesting and instructive when visiting the Naim factory to see how much care and attention they pay to keeping the lines straight in their products  and of course separation from RF interference. Having a rack to swing their power lines to induce sone form of directionality was also interesting.

Now that we all seem to be in the era of bits and bytes, it would appear to me that, apart from the density of the bits and bytes it is the conversion process from digital to analogue that 'creates' the music. Those of you who have invested in a Hugo DAC (am not one) seem to have noted an upgrade in the output music. This I can easily understand, but wonder if there is some analogue alchemy in the conversion process, akin to people expressing that there is a Naim sound. 

For some the following may be slightly heretical, but the advent of WiFi in the home and it's ever increasing speeds mean that digital data can be transferred extremely closely to the output devices and thus the potential for S/N interference can be minimised even further. Whether you like it or not, the bits and bytes cannot be coloured in any way between the host and receiver. You do not sign on to your on-line bank account and get an approximation of your bank account and for on-line dealing it would be a disaster. Anyway, those of you who have bought a Muso, including me this time, will understand that it is  the DAC, amplifier and speakers that make the music and although I am not in any way advocating a single box solution, you can see, unless you are still into vinyl, how very short straight lines might be the future.

Hi FT,

I think you'll also find that the SMPS for the Netgear switch is 'Double Insulated', so even though it has a metal case this can't become exposed to mains voltage, so, the switch doesn't require a protective ground for safety.

In fact the shield of the Ethernet cabling will provide one in practice, but as this can be disconnected, it doesn't count from the safety point of view, but as I said, 'Double Insulation' of the power supply makes formal grounding unnecessary.

This requirement for a 'Double Insulated' power supply should be noted by anyone who's thinking of fitting a non standard (e.g. linear) power supply to their networking devices.

If I'm honest I 99.99% agree with you but, for the cost of nicking some chokes and shielded lan cables from work (i.e. 'free'), then it's no real hardship to have a go and see. tbh I've got a Quadraspire EVO on order so when I do the big swap over from the Ikea Besta I'll do the cable change over at the same time. I'm still very sceptical that I'll hear anything different and it's so much effort dragging the rack out from the wall that what ever I do will stay that way anyway ;-)

Ha! Ha! Good for you and good luck, after all it is a hobby!

Nice one, Huge!

I had to look up SETI to understand it

Not heretical, but there is a potential flaw in the logic.  WiFi is a RF signal with fairly broad band modulation (also at radio frequency).  To receive (and transmit) it the system needs an antenna specifically designed to introduce radio frequency signals into the audio component.

While the designers try to minimise break-through from this, just as they try to minimise break-through from the Ethernet port, inevitably such protection isn't perfect, so WiFi introduces the same problem of RFI as does anything else (but as it requires a transmitter on board as well, it's arguably worse).

Absolutely no harm in trying - and could be a cost effective improvement.

Mike - just a quick one - although the RF current can flow to earth through the capacitor, the RFI can't shunt to earth unless the earth point (the point at which the current hits a large inductive mass like a huge metal frame chassis in an exchange/data room or an earth stake)  is less than 1/4 wavelength from the source of the RF. For 31MHz that is less than approx. 2.5 metres. 

RFI radiates alternating voltage and current EM radiation  every 1/4 wavelength. A mush of radio frequencies together will therefore radiate effectively continuously from the wire - irrespective of whether its earthed or not .

This causes one of the drawbacks, in my opinion, with combined neutral and earth system in UK TN-C distribution.

Simon

OK Simon understood,  so what is the point of capacitors coupling the case to port shields. 

I'm tempted to go measure the value,  but its a bit busy today with Bob the Builder knocking seven bells out of my hall & stairs.  

So the bits and bytes carry RF interference and cannot be isolated from the audio equipment? One, I had better not have my mobile phone when listening to music, any music. Two, I had better have Virgin than Sky as Sky must be potentially producing RF interference but Virgin is Cable driven. Three, having WiFi in my home at all must be very suspect for my musical output. 

Mostly, yes.

RFI is all around us to some degree or other.

But the best answer is simply to reduce the amount that can get into the audio components themselves, rather than intentionally increasing it by fitting an antenna.  Hence all the interest in Ferrite chokes.

Incidentally the signal from the Astra satellite (Sky) is so small and at such high frequency you don't need to worry about it.

It will lower the impedance to ground of the RF 'circuit' through which the leakage current is flowing - and depending the impedance of the conductor with the RF current compared to the source impedance of the RF then the RFI may  indeed typically reduce - but almost certainly not disappear and there will be max RFI emission from  recurring 1/4 - 3/4 wavelength points.

What EM meter are you using?

For audio and networks I rely on adding inductive ferrite clamps to impede RFI, and have paid an electrician to change my mains earthing to a TT system to reduce 'alien' noise coming in from neighbours  

Simon

Would I be right in thinking then that the shield and ferrites on shielded lan cable are largely redundant? I mean if the RF equally effects both + and - in the signal wires then the net voltage between the wires doesn't change so what's the point? Or is the shielding really there to stop stuff coming OUT of the cable?

Not really the interference we are talking here is mostly common mode - so that will radiate from the shield(s) as equally as the twisted pairs - and will radiate with respect to ground.

If there are leakages from the twisted pairs them selves and they are shielded then this EM will  capacitively couple into the shield and this coupled current will then flow through the shields to ground (either directly or capacitively through the air) - but this is as far as I am concerned for most applications here going to be extremely low level but still real.  The real risk IMO is the common mode interference radiating from the switches etc

The shielding, depending on the cable geometry, to a large extent protects the  twisted pairs from each other (cross talk)- and the also protecting the pairs from the outside world emissions (alien interference)as well as reducing emissions to the outside world.

Simon

Looking on the Netgear site, they no longer do the GS105, they now sell the new series, in both metal and plastic enclosures. However, the GS105 is still available from the usual online stores. 

Is there any benefit in a switch with a plastic enclosure. Also, do I require a fast Ethernet, or a Gigabit switch?

Thanks

Plastic is for looking smarter than metal - i.e. home/desktop use.  

Metal does have some shielding properties so is potentially better than plastic

If its out of site & would go metal,  if its visible then I would get approval from the significant other.

You don't need Gigabit for the speeds involved in audio streaming, but no harm to go for faster,  plus some golden ears on other www places say the FS series sound inferior to the GS.  

Cheers Mike...I just didn't want to get the wrong one. I thought I read somewhere, that the gigabit version is backwards compatible, or was it the other way round?   It will be out of sight, so metal will do.

Just a quick thank you to all the guys that helped and advised me, re 'switches'.

I have just ordered the Netgear GS208, which for some strange reason was cheaper than the GS205? it was half price at £12.99! Going to first hook it up to my ND5 with a 'nice' patch, then progress from there.

If there is something I need to know about this particular model, then please tell me. Still time to change/cancel my order.

Thanks again

Only comment is the ports don't appear to be metal shrouded that carries a linked ethernet shield connection across the switch.  

This means STP ethernet (Cat6a & Cat7) will not cross connect their shields,  but in some respects thats OK as it overcomes the issue of not having a 2nd earth on the LAN.   You can go all shielded (if you weely must) without worry.   

Linn has gone down the Class-D route - so I suspect they won't be impacted by SMPS units  - they themselves essentially use those units internally, no?