Review: Entreq Olympus Tellus Grounding Box

This is an article that first appeared in our new online PDF, downloadable magazine The Occasional this March in our Spring 2018 edition. We’ll be rolling out articles from it over the next several weeks in anticipation of our upcoming third issue – the Summer edition – which is scheduled for publication in May. We hope you enjoy this new, exclusive content, and that you’ll check out the current Winter Edition of The Occasional and its 140 pages of fresh high fidelity reviews, audiophile gear highlights, lifestyle stories, and editorial opinion.

–Rafe Arnott

Entreq Olympus Tellus grounding box: $9,650 USD.

They say absence makes the heart grow fond.

Or not.

From personal experience I’d have to agree with the latter. For the record, I’m talking about electronic noise here, not significant others.

Incoming power grid hash, or AC crud, radio-frequency (RF) interference, and grounding noise to name but a few of the sources that can plague the ultimate transparency to source we seek from modern (or vintage) high-fidelity playback equipment. Mobile phones, switching power supplies on laptops, bulb frequencies on halogen lamps… these all contribute an intense amount of audible pollution to the delicate signals we covet so highly from our gear because of the shared current path it all feeds from in our homes.

Some power-focused souls put in dedicated AC lines for their stereo equipment, but even that is no guarantee of a contaminate-free power source. Who here hasn’t dabbled in power conditioning of some kind? It’s like a 12-step program for many budding audiophiles. It usually starts when one realizes that power cables actually do sound different from one another. Then maybe it’s a hospital-grade wall receptacle. Our focus then shifts to the ancient power bar we have everything plugged into, and we start considering dropping serious coin on power conditioners, and regenerators or AC isolation solutions.

But what about grounding?

I have to be honest, after steadily improving my AC cables, and power conditioning, I thought I was done. Turns out I was wrong.

Not to be trifled with at over 100 pounds.

Enter the Entreq Olympus Tellus grounding box, and Eartha Cables courtesy of Edward Ku at Element Acoustics, and Wynn Wong of Wynn Audio. They told me I had to check it out, and refused to say what, exactly I should expect from it. I was skeptical, but I kept an open mind, and picked up the beautifully-crafted 100-pound, waxed-wooden box (one of their largest models) that is the Olympus Tellus (OT) from Ku, and waited for Wong to ship the Entreq cables to me. I set up the unit on the floor in front of my rack about a week later, and proceeded to hook up my preamp, phono stage, CD players, DAC/streamer, and power/integrated amps with the various Eartha cables – without connecting anything to the Olympus Tellus’s five solid-silver binding posts – and finally plugging the OT into my PS Audio P10 via a special single-pole copper AC grounding plug.

Fitting in nicely.

I did some critical listening with one of the CD players first, then connected it to the OT, and queued up the last track again… annnnnnnnnd there was no change. I listened again, and still couldn’t discern any change. I went back to my writing, and let the album play. It was during the fourth or fifth track of Only The Lonely (Capitol CDP 7484712) that I suddenly looked up from my work because Frank Sinatra’s voice had opened up, and gotten what sounded like an octave lower, his trademark croon emanating even deeper from his chest.

Ditto, the upright bass, and strings accompanying him. I went and sat down on the sofa to listen more closely, and got a weird sensation of vertigo: I felt like I was falling forward into the recording because it had opened up, and enveloped the room completely. Subtle nuances in string pressure on individual bows in Nelson Riddle’s orchestra were apparent to me for the first time ever on “Willow Weep For Me.” By the time “Blues In The Night” played my skepticism had been completely replaced with genuine disbelief. This was an order of magnitude in sonic improvement – not a change mind you – but a further absence of background noise that allowed more of the recording to be presented. The opening up of the sound stage, and the depth with which the recording could now be lensed was difficult to not be impressed by.

I proceeded to connect the pre-amp, and phono stage, and throw an LP on (Oscar Peterson – The Lost Tapes Speakers Corner/MPS 529096-1). “Gravy Waltz” sounded as I remembered it, same for “Squeaky’s Blues,” and “Let’s Fall In Love.” But when “Stella By Starlight” came on it was like a curtain was being slowly pulled back to reveal the true recording. With “Moanin’” playing the transformation was complete, and again it sounded like a window had been thrown open onto the recording session: Peterson’s piano cemented itself in 3D space about 10 feet in front of me, and exuded such realistic solidity in its felt-hammer-on-string presence as to leave me low whistling. I switched to the DAC/streamer, and experienced the same slow noise wipe, and timbral/sonic saturation that a drop in noise floor/background noise had revealed via the other sources. When I added the power amp into the mix, it went slightly blacker, but not to the same degree that it did by adding the Olympus Tellus to the sources, and pre-amps.

The fact that it took about 25 or 30 minutes for this slow bleeding-out of the noise floor to occur wasn’t lost on me. I spoke with Ku, and Wong a few days later about what I was hearing, and they agreed that they too had experienced similar results, as had their Entreq customers. Both said they let potential buyers audition whatever Entreq model they are interested in, and draw their own conclusions within the context of their own system.

OK, so it works. But what is it?

Entreq designs components that are focused on ensuring ground points that are as free from stray, contaminating  high-frequency voltages, and the magnetic fields they introduce, as possible. Why should you care, and how do they do it? The Entreq website says: “Our ground boxes/Eartha cables are designed to resemble and work like a bit of Mother Earth in concentrated form and offer the simplest and fastest route for this high-frequency noise to reach an earth point.” You should care if you’re serious about getting the best from your high-fidelity setup and how they do it exactly, is a secret – which when you’ve poured in thousands of man-hours, and your own money to research & develop, is something I respect – but basically, they are specially designed, and constructed waxed-wood boxes that contain a proprietary mix/proportion of minerals, and metals that are arranged in specific ratios/distances from one another to act as the most perfect attractor for said contaminating high-frequency voltages, and their associated magnetic fields.

With six solid-silver binding posts, the Olympus Tellus offers a lot of flexibility in large systems.

I get that some people would be nervous about technology like this because it doesn’t come with a specification chart or a bar graph, so I contacted Entreq owner, and lead designer Per-Olof Friberg in Sweden who graciously answered a few questions for me (responses have been edited for brevity/spelling/grammar).

Rafe Arnott: Many people will want to know exactly how the Ground Boxes work. I’m not asking you to reveal the secret of the sauce (so to speak) of what’s inside the boxes, but if you could shed some light – in laymen’s terms – on what the Entreq boxes do specifically, that would be very helpful. 

Per-Olof: For me to give you a correct answer, I will expose some of our secrets, but on the other hand you deserve as accurate an answer as possible to your questions. When I started I was still a farmer, and the government was constructing a new highway very close to us, including a 600-metre long bridge. There were many geologists around the site, and I learned a lot from them regarding ground composition, the difference, and capacity between sand, soil, clay soil, alumina, and so on. The conclusion was that the actual earth has a lot of electrical pollutants.

Simply put, the ground can be overloaded with electricity in some areas.That was the reason I started to test a box which is like a cross-section of Mother Earth, but one that could be isolated. If the real Earth can handle such large electrical surges/noise consisting of many Kilo Volts and MegaWatts I should be able to create a box that can handle small er currents that we would encounter in AC/speaker cables.

RA: On the website you also say: “The construction and choice of materials in the earth box has a crucial effect on the result. In part, the minerals and metals involved have an effect, but the relationship of proportion and distance between them also affects the result.”

I follow what you are saying in regards to how you come up with the ratios of materials, and their sequence/placement within the box, but why is that critical? What did you discover during the prototype stage that led to these design decisions?

PO: In the beginning we used a kind of mineral mix (sand, or more correctly, a mineral mix from a mine in Sweden) and mix it with some aluminium and copper content. Since different metals are magnetic in one way or another, and all metals have their own grounding capacity it´s important how they are placed in the mineral mix; how much, types of metals, and the distance between them to create the most efficient grounding quality. We have made great strides about which metals to use, how to prep the metal before inclusion, and use a larger variety of metals – even gold – to get increased performance.

Eartha Cables – Apollo SII AC ground cable for Olympus Tellus.

Associated equipment:

About Rafe Arnott 389 Articles
Editor of InnerFidelity and AudioStream


  1. This site is full of wonderful information, but I’m now taking everything you say with a grain of salt. From now on when reading your articles I’ll think ‘is this just another $9000 box of dirt or is this real?’.

  2. Thank you for your review Rafe
    As an Olympus owner I kept saying yes to myself as I read what you were hearing.
    Completely in line with my own experiences of this product.

  3. The author claimed he was skeptical, but the article shows us he’ll believe anything. I’m worried he doesn’t know what an octave is.

  4. for the wizard that has everything, $9k for a box full of dirt. oops a pretty box full of dirt. and I think Charles has a question that needs an answer

  5. Do not the metal particles get saturated over time ? A life span ? Why not just un-ground all components ?

1 Trackback / Pingback

  1. AXPONA 2018: The Expo Hall (Part One) – Part-Time Audiophile

Comments are closed.