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Stillpoints ERS RFI Killer

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Stillpoints ERS RFI Killer

Winner of Positive Feedback Online's 2003 Brutus award


"...Immediately the sound was fresher, purer, and seemingly unencumbered by digital artifacts..."
- Clark Johnsen, Positive Feedback (Article here)

Stillpoints ERS redirects, absorbs, and diffuses EMI/RFI frequencies. The benefits of ers for audio/video are best heard with digital circuits due to the RFI creating aspect of the circuitry itself. Benefits of ers can also be heard with AC power lines, signal cables, loudspeakers, and electronics of all types. However, in some analog circuits, the presence of EMI/RFI was tuned into the frequency response of the device. ers can effect of the amplitude of the high frequency and/or the low frequency extremes resulting in a less than desirable balance.

"...ERS has to rate right up there with the HAL-O tube dampers and the None-Felt turntable mat, as among the highest values in high-end audio..." - Rick Becker, (Article here)

What's it made of?
The core of ers is made of a blend of carbon fibers of various lengths and sizes. Using a proprietary method, these fibers are coated with metals, such as nickel. These fibers absorb, reflect and diffuse RFI/EMI. ERS has on average about 66 db noise reduction in it's 10meg to 17 gig range. this is all that we can claim, due to it's defense restrictions.

The exterior is laminated with a polyester textile on both sides to make the material easier to handle and use.
This is the base of ERS.

ERS may all be purchased with a pressure sensitive adhesive already applied for easy and quick installation.

The edges of ers do have exposed conductive fibers and should be handled and installed with care. The electrical resistance of ers is .026 ohms per square yard.

The polyester fabric will insulate the core of ERS, to some degree, but can be easily penetrated with sharp edges. Caution should be exercised when used in close proximity to circuitry.

ERS is treated to accept many laminating resins such as epoxy and polyester resins.


Frequency Attenuation (dB)
10 Mhz 49
100 Mhz 48
200 Mhz 62
400 Mhz 53
800 Mhz 54
900 Mhz 50
1 Ghz 49
2.4 Ghz (802.11B, wireless networks, cordless phones) 53
3.5 Ghz 54
5.8 Ghz (802.11A) 57
7.5 Ghz 61
10 Ghz 66
17 Ghz 55

Why is it necessary?
With the exception of high end cables, EMI/RFI shielding is rarely, if ever a consideration when designing audio components. Yet it is one of the biggest culprits when it comes to sonic background noise and "edginess" exhibited by some audio gear. Manufacturers want to control costs, and adequate EMI/RFI control is not high on the list of priorities.

With the availability of ERS, one is now able to address this problem in their own system in a cost effective manner. Also noteworthy is the fact that since ERS does not operate under the same principles as a shield, it does not require grounding.

Useful Applications
A simple demonstration of the potential effectiveness of ers is to lay it near any digital circuitry, for example, on top or underneath or at the sides of a cd player or dac or digital amplifier. Wrapping AC cables or placing ers near any AC power strips will also quickly show its potential. However, its effectiveness will be maximized when placed internally near either EMI/RFI generating or EMI/RFI susceptible circuitry within the enclosure. The enclosure itself, traps on board generated EMI and RFI which ers absorbs, deflects and diffuses. ers does not operate under the same principles as a shield thus it does not require grounding.

The amount of ers used is component dependent and must be experimented with. We have noticed that 100% coverage not necessary. Fine tuning may result in very little material required.

Listed below are just a few ways in which ERS paper has been used to control and absorb EMI/RFI.

  • In general, lining the inside of a component's top cover is a good place to start. If you don't want to open up your piece of equipment, then just lay the sheet on top. 
  • CD/DVD players - attached to the underside of the top, and attached to the bottom. This covers the power supply, and the digital ICs. Digital is probably the most notorious EMI/RFI polluter in a system.
  • Preamp/ processors - attached in a similar manner as the CD/DVD player.
  • Home theater processors - Treat similarly to the DVD/CD player.
  • Electrical outlets - Cut in the same shape as the wall plate and place over the outside of the wall plate. The ERS is placed on the outside of the wall plate because it IS conductive.
  • Power conditioners - wrapped around power cords, and covering the top, bottom and sides of a power conditioner. A very effective tweak.
  • Power cords - Wrapping the cord with ERS tape. We have had excellent results doing this. 1" tape works well. Multiple layers work well too.
  • Power transformers - Keeps stray rfi and magnetic fields from interfering with the audio signal.
  • Crossovers - Covering the top bottom and sides, as well as wrapping the internal wires. This method needs to be "tuned" to each individual system. You will know when you've added too much ers, when the highs start rolling off, or midrange detail starts disappearing. Be prepared to spend some time on this.
  • Interconnects - Wrapping the interconnect with ERS tape. This too will require some fine tuning. I use a 1/4" strip wrapped around the very end of the RCA connector's outer shell. You may also try spacing the ERS away from the cable via foam pipe insulation.
  • Loudspeaker cables - Fine tuning required here as well. Start at the end that connects to the loudspeaker. You may also try spacing the ERS away from the cable via foam pipe insulation.
  • Video Cables - Component, composite, coaxial, and S-vhs cables all benefit. Wrapping the entire cable provides the most benefit in this case


How much do I need?

Hitting the level of diminishing returns with ERS is difficult, and system dependant. Below are some minimum guidleines for using ERS. 

  • Great results have been achieved by using the ERS tape to wrap power cords and interconnects. If you are odering 1" tape, generally you will need TWICE the length of whatever cord, interconnect, etc. you are trying to wrap. An alternative to wrapping is to lay the ERS length wise down the cord. This may take two, overlapping runs to completely cover the cable, but it is a time saver. ALWAYS do a "test wrap" before removing the adhesive backing!
  • For lining the top cover of a component, a minimum of two sheets are generally needed.
  • For an amplifier, be sure to cover the area above and below the power transformer at the minimum. It takes about 1 sheet to do so.

4 Reviews Hide Reviews Show Reviews

  • 5
    Stillpoint ERS Killer

    Posted by Charlton White on 3rd Jan 2021

    Exceptional, use on power supply and sensitive equipment.

  • 5
    Need to know how to use

    Posted by Matt on 8th Mar 2017

    OK, my system is based more for a home theater than pure stereo system. Power is fed from an aftermarket outlet to a Furman 15 Pfi, from there to each component. A Panasonic DMP-30 BluRay and a Marantz SR7008. The front l/r speakers use the Marantz as a pre only and send this signal via Kimber Kable Hero to a NuPrime STA-9 to JBL ES80 speakers by way of Kimber Kable 8VS jumped with Analysis Plus Oval 12 inch jumpers. The center is a JBL LC1 with Audioquest Rocket 33, single bi-wire. My TV is a Panasonic plasma. All HDMI and power cables are Pangea and heavily shielded; the HDMI 4% silver plate. So the 1st application of the ERS cloth was with some help from the Head Geek at Tweek Geek. Upon talking to him I used some 600 volt standoff electrical tape and made a make-shift shield from a piece of ERS cloth to put around the transformer in my bluray. By using the tape there is no chance of a short. I also put a single layer on the top cover over all circuitry (digital) and also a small electrical tape covered piece under the transport mechanism where other circuitry (digital I imagined). I also made a few electrical tape/ERS cloth panels to put around where the HDMI input is. BTW, all inputs/outputs to the BluRay, TV, Marantz are covered with RF/EMI blocking caps which have been shown to already work. When I played my first disc (a DVD-Van Helsing); the results were obvious. Greater depth of field in the picture, less snow noise, more video details. The same, as I recall, held true for audio, but to a lesser degree. With my RCA caps, it seems that the RF/EMI hash caught in the system takes time to get flushed out and the video is more immediate to be observed. The rest of the ERS cloth was used on my Furman conditioner. I covered the whole top panel and then put an additional sheet in the middle 1/3, near the circuit boards I put as much as was practical in the electrical tape to surround them without touching them and lined the nearest side panels (as much as was practical) with the ERS. This 'tweek' was harder to discern because I also added 6 Bybee QSE's at the time and also a new cable splitter (made with beryllium copper contacts and reduced cross talk between I-net and TV signal) and a TV signal amp that provided 14 dB gain. Anyhow, the results were obvious; but I dont know how to dissect one from another at this point. The 1st thing I watched was the Munsters on a local station. The blacks blacker, the whites whiter and the difference between seemed to improve (the contrast I believe). All the background artifacts again came out more than I recalled and same as the definition of the audio (through my TV speakers) and the definition improved in the picture too. I would apologize for this epistle, but I am new at this and at this point any information is hopefully helpful for anyone out there. The way these need to be used (from what I have gathered) is on the interior of the component, unless one makes a Faraday shield over a component. The reason is all the digital chips and power supplies give off the RF/EMI and it just pings around the inside of the enclosure and this stuff is like a sponge.

  • 4
    They work Ok

    Posted by Unknown on 29th Nov 2016

    They work Ok. My Marantz Super Audio Cd player was the one piece who show more improvement using the Stillpoints ERS RFI Killer. Nothing spectacular

  • 3
    RFI Sheild?

    Posted by Unknown on 20th Jul 2016

    As per the Tweak Geek site placed a small square ERS paper under head shell above cartridge leads. Possible small improvement, could be added weight/mass ?? Will continue to try other applications.