Absorption of digital hash

Berkeley uses material to absorb stray digital noise. Anyone know what they use?


Ferrite is commonly used (ceramic form of oxides of iron).  You can get in various forms, including products designed to clamp around eires for this purpose.  There are also other electromagnetic blocking materials that come in useful forms such as cloth, tape, etc.  

Post removed 

I use Mu Metal foil to shield my step up transformer from external EM fields and resulting noise. Works great.  The difference in noise levels is clearly audible. 

I used my golden plate homemade device : a plate of shungite with an external copper tape face + in some case mineral as quartz to fine tune the sound...😊

I used mostly  very thin plate unlike the example of this image


Thanks guys. I've found Holland Sheilding System as a result of your helpful comments. Now will do some shopping :)

OP:  Not sure what you are doing, but please keep in mind the heat dissipation of some devices.  Wifi routers especially need a lot of airflow to function at top speeds, and may even shut down.  Modern, Energy Star compliant Ethernet switches should be fine though. 

@erik_squires . Like to improve my Oppo 205 without any upgrades. Just read about Berkeley as I'm considering dac upgrade ( or Spectral spinner). Still love disc movies on my Sony 4k. Mu metal for transformer 'may' be interesting. I'm just getting back to listening. Been busy w project. Relaxation coming up-again :)  Time to ponder hi-fi improvements. Your comments always interesting/informative/ mannerly :)

Just be aware that proper EMI/RFI interference shielding requires significant engineering knowledge and it is best done by professionals and requires very expensive specialist equipment. I see little point in trying ad-hoc solutions, it is very difficult to achieve a good shield at home. Do you really have a EMI/RFI radiation issue and how does it manifest itself?

@greg_f . In a review of Alpha Reference mention of "material" added to absord radiated digital noise, nothing complicated.

This is the comment from Mr. Harleys' review of the Dac 3. I'd like to know the material.

"When I removed the Alpha 3’s top panel, I noticed a square of material above the digital-to-analog conversion section, just as in the Reference. This ultra-expensive material absorbs and diffuses RF energy. Noise radiated by circuits is absorbed rather than being reflected from the top panel back into the circuit board."



I just don't believe you can slap a little bit of some 'magic' material to tackle emissions. EMC compliance (includes RFI/EMI emissions) is big business in Europe and companies spend millions to ensure their products meet the requirements at all stages of product development.  At the design stage you account for emissions and you control them using various design techniques. Then there are several stages of EMC testing before a product is released to production.

If you believe you have emissions issues you need to measure it and then decide what to do about it. I am assuming that you mean emissions when you say stray digital noise. What do you think is the root of it, where is it coming from?


+1 on shungite, @mahgister is right


Why did you say that ?

How dare you ?😉


Please explain a bit why if i am right ?

If not this one line did not say much... 😁

Thanks ...

I put shungite between tubes and tranformers on my Wavac EC300b as well as on top of all my power supply transformers. Clarity and Impulse!

Thanks it is good to know for anyone...


Now try some quartz or herkimer diamond near the shungite or in his place at some point to reach an even better balance ...Experiment and listen to aim at the right balance and spots...

Shungite tend to compress sound ... ( it shield from EMI too )

Quartz tend to decompress it ...

balance is key ...

I put shungite between tubes and tranformers on my Wavac EC300b as well as on top of all my power supply transformers. Clarity and Impulse!


@ptss That plate is Permalloy. It has magnetic properties similar to Mu metal but is much less ductile. Mu metal can be formed easily into various shapes. 

I have digital equipment all around analog gear and I don't have to shield anything. I do not have any interference or mystery noise. I spend my money on records and not trying to fix problems I do not have. The solution is not to buy equipment that is inadequately shielded.  

Thanks for all helpful responses. I don't have a problem I have an Oppo 205 and thought if this material is good enough for Berkeley it's probably goid enough for Oppo. I have no complaints with my Oppo. 

@mijostyn Totally agree. if a product is emitting RF or whatever then it is not fit for purpose and shouldn't be in the market.