What are you doing about EMI/RFI?

dcathro

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Sep 16, 2016
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The mention of this product in another thread had me wondering what people were doing, if anything to combat EMI/RFI.

Are you relying on power conditioners or are you taking other measures?
 

SlapEcho

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Dec 15, 2021
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Lol...everywhere. It started when I put a nondescript ferrite bead on the 5v supply for the CAS SSD. It squealed like a county fair greased pig when turned on. I then realized for the ferrite bead to sound as it did the SSD drive must pull significant amount amounts of peak current and that had to be radiating RF within the server. I ended up wrapping each common voltage rail wire assembly that I could with copper then shielded with fabric tape. Each cable assemly copper tape was then soldered with a piece of wire then star grounded to the server chassis. Both ends of these wires I also added mix 31 ferrite beads. The improvement in sound was unreal. I've observed the more RFI is decrease, the more articulate the bass becomes(there are now notes riding the bass lines rather then being one note). This is also accompanied by seemingly higher and higher treble extension. I once ask myself while sitting close to a jazz ensemble at a restaurant(I think Top of the Hub) why the cymbals didn't sound as realistic and extended when listening at home. Cymbals where extended, brash, startling, but didn't make me want to run to the door; I now know why. At the same time nasty siblances(which is a hallmark at least to me of most CAS) in female vocals was also decreased.
 

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SlapEcho

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I then made did what was supposed to be a test trial shield for the JCAT XE USB card but decided it was decent enough to permanently keep. This uses 14 gauge copper with the inside covered with a polymide sheet to keep the backside of the USB card from shorting to the shield. It is then covered in the 3M RFI absorber mentioned above. There is a 1" x 1" hole thru the polymide and rf absorber where I placed 2mm of thermal pad to sink heat from the voltage regulator from the board to the shield. All in all, also a very noticeable improvement in sound quality following the same lines that I mentioned before. I added more of the 3M material around the bottom and topside of the motherboard around the USB card and drives. Same deal as far as improvements go.
 

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SlapEcho

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Not going to get into details unless asked but the same mindset when it came to the Benchmark DAC and two Velodyne bass crossovers. I got this reading one of Ack's old threads. This had the effect of "drying out" the sound. Everything initially sounded softer. At first I thought maybe I had placed too much but then realized I was turning the volume higher to compensate and getting way more detail back from audio playback than previously before. It seemed as if the 3M material dampens resonances/irritations that normally I would assume were a by product of playing too loudly(e.g. - the amplifier running out of steam). This was heard throughout the audio spectrum. Resolution also seemed to increase massively.
 

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SlapEcho

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For poops and giggles I decided to make a usb cable. I've seen on these forums alot of talk about upgrades in cables also leading to auditory improvements. I've tried a few lower end cables but I've felt that the improvements I heard may be placebo. I first tried shielding and grounding a Oyaide S cable I had. Soundstage opened up alot. I've done some USB PCB design and RF antenna cable work before so I decided to give it a shot. Stipulation here - i did not, nor do not plan to properly test what I made(i.e. - scope for USB eye). Just trusting my ears and calling it a day. In a nutshell, in order from inside the cable to the outside: 100 ohm quality twinax cable -> polyethylene foam -> teflon tubing -> 3m absorber -> fabic tape -> copper tape -> fabric tape -> expandable braided sleeving. Two of these were made one for 5V/GND and the other for USB's D+/D- pair. Top everything off with USB connectors, heatshrink, and grounding cable for the copper tape. The thought process was to create an anechoic connection from CAS to DAC and try to keep the shield reasonably away from the cable it's so to not effect the cables impedance.

Take what I'm saying with a grain of salt. These are just my opinions and nothing more. When I grounded(I can hear a difference when or when it's not) the cable and pressed play I was not prepared for what I heard. The soundstage is now transformative. It can go from dry(e.g. - a recording booth) to massive. I've heard people talk about getting depth within their walls. I've had varied experiences with this but not to this extent. When called for I can easily hear 15+ feet into the front wall soundstage. It is startling to hear what sounds like a small booth with one track, then to suddenly explode to a large soundscape. Tool's Choclate Chip Trip track comes out from the left and right speaker +4ft at the hard left and right of the speakers. I've never experienced this before but there is significant soundstage height when called for when with live stadium music. I could go on...

Again, just my 2 cents.
 

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dcathro

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Hi SlapEcho,

Thanks for sharing in such great detail!

Wow you have really taken the issue seriously.
 

LL21

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We are using a few things that have worked well:
- Within Zanden's original design, practically everything has this shielding across individual pieces. Something that Yamada San has already done for you in his digital
- Additionally, we use Waversa INT LAN Reference Plus which basically takes each of the 8 strands of an i2s digital cable and runs each strand through some kind of magnetic or field or something inside...and then puts all 8 strands back together on the other side to connect into the DAC. Supposedly about RMI/RFI...works EXTREMELY WELL. More resolved, in fact FAR more resolved...word clarity is our biggest clue in that, but the images shimmer even less than before and are still and resolved in their own space better
- Plus, we use Entreq Wraps, Entreq Paper around cable inputs/outputs which do seem generally to quiet down a sense of grunge, the signal appears a bit denser, more resolved
- I have no idea what the Tripoint/Entreq Grounding boxes do...but they WORK, and if they also reduce emi/rfi, so be it. More of the above.

In fact, all of the above has been about finding a voice we like...source, amps, speakers...and then HONING with this by removing noise as much as possible. Signal basically feels much purer and the original voice is simply a better version of itself - unchanged in terms of organic character.
 
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Gregadd

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@!#$%^&*!o_O
 
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dcathro

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Here is the approach that I have used:

- I use a large isolation transformer on the mains
- My interconnects have RFI draining networks
- I have placed ultra high frequency RC low pass filters in my speaker crossovers, across the drivers and across rhe field coil power supplies.

I have tried and really don't like shielded cables or ferrite rings. I have not tried any grounding boxes.
 
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Mark (Basspig) Weiss

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Faraday shielded the entire house, as we knew there is a 50kW FM tower 1400' in our front yard.

As a broadcast engineer, I have had to deal with resident complaints in apartment buildings of RFI from one of our transmitters on the roof in Yonkers. Solutions ranged from aluminum foil, to looping the line cord 4 turns about 2" diameter and tying with zip ties. Mix 31 clamp on chokes are also an excellent helper for these problems.

In this day and age, I'd be more concerned about protection from EMP events though.
 

SlapEcho

Member
Dec 15, 2021
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Here is the approach that I have used:

- I use a large isolation transformer on the mains
- My interconnects have RFI draining networks
- I have placed ultra high frequency RC low pass filters in my speaker crossovers, across the drivers and across rhe field coil power supplies.

I have tried and really don't like shielded cables or ferrite rings. I have not tried any grounding boxes.
Ferrite rings/beads/chokes have not been my preferred choice in the past. I'm a bit biased against using them on audio signal cables with what I find are deleterious effects. I do find them useful on switching power supplies though and as mentioned before when used on all a/c lines at the breaker box with the exception of the mains coming in and the dedicated lines to the system. I do have a few sitting on some power cables but use them sparingly as I noticed they can blunt dynamics and the high frequencies. Trial and error here.

The did you purchase interconnects with RFI draining networks on them or are the networks custom? Off the top of my mind I can't think of any commercial non-shielded cables with networks on them. I find it an interesting take.
 
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Gjo

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Aug 22, 2021
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A few years ago, I began a quest to identify and reduce EMI/RFI. I purchased a couple testing devices, and began the process.

I tried a number of power conditioners, filters and EMI/RFI reducing products marketed to audiophiles. None of them had much effect reducing EMI/RFI.

The only devices that performed as promised and significantly reduced EMI were CleanSweep filters made by OnFilter.

If you're seeking to reduce or eliminate EMI/RFI, I encourage you to give these a look. Read the posted articles, and perhaps reach out to the owner, Vladimir Kraz, for more in-depth info.
 

dcathro

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Sep 16, 2016
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The did you purchase interconnects with RFI draining networks on them or are the networks custom? Off the top of my mind I can't think of any commercial non-shielded cables with networks on them. I find it an interesting take.

They are bespoke and hand made by Chris Bryant in the UK.
 

rpk

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Aug 30, 2020
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The mention of this product in another thread had me wondering what people were doing, if anything to combat EMI/RFI.

Are you relying on power conditioners or are you taking other measures?
Hello dcathro,
since I was interested in the 3M EMI sheet product you mentioned, I ordered two copies in the 1mm version a year ago.

Item: https://www.mouser.de/ProductDetail/3M-Electronic-Specialty/AB5100SHF?qs=gMfM3zrbS4r0qTugzC4tdw==

Datasheet for series 5100 = https://www.mouser.de/datasheet/2/1/846522423eaf927ed1f5720cd4d46e04fa361b66-2951889.pdf

The individual test with the sheets:
The advantage of the DIN A 4 sized sheets is that they can be placed in a variety of locations for familiarization without removing the adhesive foil.
Thus provisional layout combinations (optically visible) can be designed externally: Covering housings of individual components, wrapping short cables, etc. Depending on the size of the components, several sheets may be needed.
Comparisons with vs. without are time consuming, but provide the desired information. For example, on my DAC (sheet metal enclosure) the EMI sheets showed no effect, on enclosures of mono power amplifiers (tubes) a cleaner presentation when combined from the outside in the area of the power transformers.

Should the sheets become advantageous at any position in the system, they can be cut cleanly and then used invisibly inside the housing.

Experiment creates knowledge!

Good success with upcoming projects wishes Rainer
 
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dcathro

Well-Known Member
Sep 16, 2016
571
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Melbourne, Australia
Hello dcathro,
since I was interested in the 3M EMI sheet product you mentioned, I ordered two copies in the 1mm version a year ago.

Item: https://www.mouser.de/ProductDetail/3M-Electronic-Specialty/AB5100SHF?qs=gMfM3zrbS4r0qTugzC4tdw==

Datasheet for series 5100 = https://www.mouser.de/datasheet/2/1/846522423eaf927ed1f5720cd4d46e04fa361b66-2951889.pdf

The individual test with the sheets:
The advantage of the DIN A 4 sized sheets is that they can be placed in a variety of locations for familiarization without removing the adhesive foil.
Thus provisional layout combinations (optically visible) can be designed externally: Covering housings of individual components, wrapping short cables, etc. Depending on the size of the components, several sheets may be needed.
Comparisons with vs. without are time consuming, but provide the desired information. For example, on my DAC (sheet metal enclosure) the EMI sheets showed no effect, on enclosures of mono power amplifiers (tubes) a cleaner presentation when combined from the outside in the area of the power transformers.

Should the sheets become advantageous at any position in the system, they can be cut cleanly and then used invisibly inside the housing.

Experiment creates knowledge!

Good success with upcoming projects wishes Rainer

Hi Rainer,

Thank you for posting your experience!

I will certainly try and get some of this material to experiment with.

Best Regards

David
 

SlapEcho

Member
Dec 15, 2021
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Just to note - There are multiple vectors of RF radiation, externally (e.g. - Wifi or cellular), and internally within the system component themselves(e.g. - switching supplies, even pcb trace to trace crosstalk).
 
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Cycling Nut

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Just to note - There are multiple vectors of RF radiation, externally (e.g. - Wifi or cellular), and internally within the system component themselves(e.g. - switching supplies, even pcb trace to trace crosstalk).
SlapEcho,
What kind of cloth tape do you use?
I'm using YC industrial cloth tape for Wiring Harness Automotive. I have to heat it with a hair dryer to get it to stick. Ive read other tapes have a similar problem. Thanks!
 

SlapEcho

Member
Dec 15, 2021
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SlapEcho,
What kind of cloth tape do you use?
I'm using YC industrial cloth tape for Wiring Harness Automotive. I have to heat it with a hair dryer to get it to stick. Ive read other tapes have a similar problem. Thanks!
Nothing super fancy. Just regular adhesive backed tape. It doesn't hold the shape as well as the type you need to heat up, so its a bit more pliable, but for this specific use case it does the job. This one worked well for me. - https://www.amazon.com/HSTECH-Autom...+Wire+Loom+Harness+Tape&qid=1672241843&sr=8-2
 
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