Faraday Shielding of Cables

[MF 1000]

After the tread discussing using Mu metal inside a mc step up granny case I was looking for self adhesive mu metal and came across so called faraday tape and fabric use to create isolation pouches for mobiles, credit cards etc.

Had some credit in my Amazon account after a returned item so I splashed out £25 on a 1m sq piece of cloth and 10ft of tape.

Warmed up my system this afternoon and used Big Boy Blues off Yello Point as a test track . I simply cut a 5 “ wide strip and wrapped it around my home brew silver core digital cable with multiple ferrite shields on it, holding in place with a few strips of sellotape.

Back on with the track and all was good …no night & day stuff but a crisper edge to drumsticks on hi hat cymbals. Off with the fabric and the reduction of sharpness was noticeable. Jane will now be using her sewing machine skills to create a fully sealed fabric tube which I’ll seal to the BBC’s plugs at either end with the tape. Update tomorrow with full pics

here is the fabric

 

[MF 1000]

Jane made up a nice sleeve out of the cloth tonight and I slid it over my foo digital cable, securing it onto the bnc connectors at either end with the self adhesive faraday tape.



A quick spin up of Big Boy Blues again and the crisper top end ….drum sticks in a hi hat cymbal etc is still there

 

[zeta4]

Interesting find but when I mentioned it to herself I got "that look" !

 

[rabski]

The one thing that concerns me is the 'step up granny case'. I suspect social services may be wanting a word

 

[Fourlegs]

Jane made up a nice sleeve out of the cloth tonight and I slid it over my foo digital cable, securing it onto the bnc connectors at either end with the self adhesive faraday tape.

A quick spin up of Big Boy Blues again and the crisper top end ….drum sticks in a hi hat cymbal etc is still there

Keith, as ever your playing is interesting and I look forward to trying it out!! The only thing that slightly concerns me is that I would normally associate the differences in SQ you mention as being due to ‘more’ RF noise rather than ‘less’!!

Is the fabric conductive and if so could it be allowing RF noise to flow in the ground plane along the fabric where previously it was stopped by your ferrites?

 

[MF 1000]

Would be quite an interesting one …more RF making hi hat cymbals etc crisper ….what a frustrating ’hobby’ we involve ourselves in

here is the fabric I sourced via Amazon

GORGECRAFT EMF Protection Fabric, EMI, RF & RFID Shielding Copper Fabric 42.71x41.92 inch Faraday Fabric Shielding Rating from 10khz to 30Ghz​

 

[Fourlegs]

Would be quite an interesting one …more RF making hi hat cymbals etc crisper ….what a frustrating ’hobby’ we involve ourselves in

The mechanism is that when RF noise gets into the DAC analogue stage it creates intermodulation distortion and that generally manifests as an emphasis on percussive notes, greater soundstage, exaggerated detail etc etc but these are all false and are merely distortion generated artefacts which ultimately translate through to the music being more fatiguing.

Even low levels of the IMD are quite audible.

Reduced RF noise in a system on the other hand is heard as a calmer sound and less ‘in your face’. It might initially seem to have less detail but listen again and usually it turns out there is more real detail revealed when the noise artefacts are not there to mask it. Percussion notes might seem to have less thwack but they will probably have more texture and you can probably hear what material is creating the percussion note.

 

[John (big)]

The mechanism is that when RF noise gets into the DAC analogue stage it creates intermodulation distortion and that generally manifests as an emphasis on percussive notes, greater soundstage, exaggerated detail etc etc but these are all false and are merely distortion generated artefacts which ultimately translate through to the music being more fatiguing.

Even low levels of the IMD are quite audible.

Reduced RF noise in a system on the other hand is heard as a calmer sound and less ‘in your face’. It might initially seem to have less detail but listen again and usually it turns out there is more real detail revealed when the noise artefacts are not there to mask it. Percussion notes might seem to have less thwack but they will probably have more texture and you can probably hear what material is creating the percussion note.

For my non optical links to my DAC I use Webro WF100 coaxial cable that uses copper foil & stranded mesh shielding which I believe acts as a faradic cage as well as ground/return. I particularly as I use F type connectors, 2 with phono plug screw in additions as appropriate. High quality triple shielded HDMI leads.

However despite my attempts to only use F type & BNC output from CD player & HDMI leads. living on top of a hill surrounded by RF from two airports multiple large mobile phone masts and the vast array of transmission aerials on buildings in Ealing Broadway. I still had RF noise.
My answer was clip on ferrites 60 plus every time I added a ferrite to the Virgin box to TV or the DVD player to TV the picture resolution improved, the same was true of my sound system I stopped adding ferrites when little or no improvement was evident. I was told by a painter who had RP & RA after his name when little or no improvement was evident or it took minutes to find a place to add paint the painting was finished.

I have ferrites on all digital & power leads none onn phono leads where they are counterproductive.

As Fourlegs states "Reduced RF noise in a system on the other hand is heard as a calmer sound and less ‘in your face’. It might initially seem to have less detail but listen again and usually it turns out there is more real detail revealed" I can't measure the reduction of RF on the audio though my golden eared son said on Tuesday it had never sounded so good. The TV picture quality I can quantify as I can see the difference it is like the difference twixt the old VHS quality & DVD digital quality, though I do thankfully now have 4k TV of high quality as have family who have no RF problems.

 

[zeta4]

Is 60 plus the ferrite mix or do you have 60 plus ferrites in your system ?

 

[John (big)]

60+ ferrites in system, though probably nearer 80.