pl | en
Headphone cable
Entreq KONSTANTIN 2010

Prices (in Norway):
HiFiMAN - 390 Euro/2,2 m ǀ 450 Euro/3,3 m
Sennheiser HD 800 - 510 Euro/ 2,2 m ǀ 570 Euro/3,3 m

Producent: Entreq

Per-Olof Friberg ǀ Rönnetorp ǀ 265 90 S-Åstorp ǀ Sweden
tel.: +46 (0)705 200 500 ǀ fax: +46 (0)42 520 50



Country of origin: Sweden

Product provided for testing by: Entreq

Text: Wojciech Pacuła | Photos: Wojciech Pacuła | Entreq
Translation: Andrzej Dziadowiec

Published on: May 1. 2012, No. 96

Led by Mr. Per-Olof Friberg, the Swedish Entreq is one of a fairly large group of micro-companies offering their products and services to people who – shortly speaking – know what they want. Here I mean experienced audiophiles who seek a change for the better in the areas that others only begin to see; those who are aware of the fact that where it comes to sound everything is important, literally every detail. In case of Entreq they offer equipment racks, stands, vibration damping and isolating accessories, products used to improve the quality of voltage supply (mains), interconnects, and other, sometimes quite esoteric products such as Minimus, which connects to the equipment (or terminal supply) ground and reportedly has a positive impact on signal quality. And although Acoustic Revive offers a similar product, Ground Conditioner RGC-24, it is still one of the most exotic pieces of audio equipment that I have seen (I will test review both the RGC-24 and the Minimus in some time, when I cool down...). Against such background, the headphone cables from Per-Olof Friberg appear to be rather a “mainstream” product.

All Per-Olof’s products are linked by one common idea: to minimize vibration and to minimize the amount of metal and plastic around the conductors. Thus, on all his products we find the inscription that is the motto of the company: Energy Transforming Equipment; the main construction materials are wood and cotton. The designer writes about his design assumptions as follows:
“In terms of technical assumptions, we deal with a lot of small components working together. The most important objective is, however, using the least amount of metal and plastic. The signal path should be as short as possible. We also try to reduce the magnetic field. The positive and the negative signal lines are built differently and have a different length. The point is that there should be no “crosstalk” through magnetic field.”

The reviewed cable comes from the Konstantin 2010 series and is produced manually by Per-Olof, from A to Z. That even includes the 6.3 mm jack plug. Instead of metal or plastic, its casing is bored and milled from a piece of wood. We can see the other similar component where the cable splits into two separate wires, going to the left and right earpads. The cable features black cotton wrapping with white thread. The company offers cables for several different models of headphones, including the Sennheiser HD800, the AKG K701 and the HiFiMAN headphones. For my test review I ordered cables for the Sennheiser HD800 and the HE-500 from HiFiMAN.


Recordings used during listening sessions (selection):

  • Audiofeels, Uncovered, Penguin Records, 5865033, CD (2009).
  • Beverly Kenney, Lonely And Blue, Cellar Door Records/Sinatra Society of Japan, XQAM-1022, CD (2007).
  • Chet Baker, Chet Baker Sings and Plays, Pacific Jazz/EMI Music Japan, TOCJ-90028, HQCD (2008).
  • David Sylvian, Sleepwalkers, P-Vine Records, PVCP-8790, CD (2011).
  • Joe Pass, For Django, Pacific Jazz/EMI Music Japan, TOCJ-90027, HQCD (2008).
  • Johnny Holiday, Blue Holiday, Contract Records/Sinatra Society of Japan, XQAM-1014, CD (2007)
  • Josquin Desprez, Missa D’ung aultre amer, Motets & Chansons, wyk. Alamare, dyr. David Skinner, Obsidian, CD701, CD (2007).
  • Julie London, Julie Is Her Name. Vol. 1, Liberty/EMI Music Japan, TOCJ-90014, HQCD (2008).
  • Marek Biliński, Mały Książę, Bi.Ma, BiCD-09, CD (2010).
  • Nosowska, 8, Supersam Music, SM 01, CD (2011);
  • Pat Metheny, What’s It All About, Nonesuch Records/Warner Music Japan, WPCR-14176, CD (2011);
  • Paul McCartney, Kisses On The Bottom, Universal International [Japan], UCCO-3038, SHM-CD (2012).
  • Pieter Nooten & Michael Brook, Sleeps With The Fishes, 4AD, GAD 710 CD, CD (1987).
  • Ralf Illenberger, Red Rock Journeys, Stockfisch, SFR 357.1020.2, CD (2011).
  • Sibelius, Symphony No. 1 & Karelia Suite, Maazel, Decca/Esoteric, ESSD-90020, SACD/CD (2008).
Japanese versions of the CDs available at CD Japan

Entreq Konstantin 2010 + Sennheiser HD800
This is not the first time I deal with headphone cables designed to connect different models from HiFiMAN, AKG, and Ultrasone. Replacing the cable on these headphones is simple, which prompted various companies to offer their own replacement for the “stock” cable.

But I must say that so far this type of “fixes” seemed to me not worth the money, or even not to make any sense. Often, changes introduced by new cables went not forward but sideways, and usually not quite in the direction that I would have dreamed of. Problem is that they usually sharpened the sound. It was more resolved, which was a plus, but almost always it was at the expense of the overall tonal balance and coherence of the sound (which was worse). That is why I never wrote about it as it seemed to be not worth of my effort (writing) and yours (reading). The mediocre is not worth our time. That experience was, however, not without an important lesson: the headphone cable is an integral part of the headphones that clearly shapes their sound and must be carefully chosen to make the headphone system (since the headphones with the cable, as a replaceable component, and the amp are a system) sound in the maximum balanced and coherent way. And the cable, as it turns out, plays an important function in this – it allows us to hear how the headphones really sound. It will not improve anything if the transducers and their application are bad, but will rather help to bring out their best.

Sennheiser HD800 are one of the best, if not the best dynamic headphones. At least among those I know. In their case we could only try to improve signal transmission between the amplifier and the transducer, without changing its characteristics; after all, it is only two meters of cable, isn’t it? And yet, Konstantin Entreq 2010 is the first cable to change their sound in a dramatic way and in a clearly positive direction that fits perfectly with my idea of how these headphones should sound.
Swapping the stock cable for the Entreq we get much more energetic sound. It’s the first thing that quickly strikes the eye (or ear). It’s like changing a pair of fine-sounding but a bit boring loudspeakers for my Harbeths – the improvement is vast and (literally) bodily felt, so to speak. With headphones we do not have the effect of air pressure that affects our body, only our ears, but we get a similar impression as if our brain remembered our experience with the loudspeakers and repeated, albeit in a smaller scale, that “saved” experience. It was best heard on David Sylvian’s tracks from Sleepwalkers , where it is one of the determinants of the overall system quality. There was power, there was fullness and saturation. It is important with this album because the vocal was recorded very close, it has a very large volume, and for these tracks to make sense it has to be delivered that way. With the stock cable it sounded very good, no complains. That is, until I heard how it could REALLY sound.
And all this without brightening. For brightening is what really ticks me off; it gets on my nerves more than anything. The Swedish cable sounds much cleaner than an ordinary cable, in the way that a good amp does – lower distortion, less noise, etc. translates into the kind of sound that can be described as warm. And so it is in this case. The top seems to be sweeter, and the bottom deeper. The midrange is warmer and has a better mass. The differentiation improves significantly – if low and high sounds are superimposed, e.g. in electronic music, the Entreq will show the difference more convincingly; it will better isolate and better describe the sound. That happens because everything gains weight with it – both cymbals as well as guitar, like Joe Pass’s from his For Django album.
Yes, it is definitely a better cable, a couple of lengths better than the stock cable. The first one that does what I would expect. Maybe I’m a little spoiled with my Harbeths M40.1, but I see that I go for that type of sound, wherever possible – energetic, saturated, differentiated, with deep bass. The Entreq Konstantin 2010 gives me all that in one go.

Entreq Konstantin 2010 + HiFiMAN HE-500
Changing the HiFiMAN headphones cable I more or less knew what to expect. As it turns out, the changes introduced by the Swedish cable are quite similar, regardless of what kind of cable it replaces and which headphones it works with – be it dynamic, as the Sennheisers, or magnetostatic as the HiFiMAN.
The sound is deeper and richer with it, although you cannot pinpoint the range or even the regions of audio band in which there would be perceptible change. The fact that we perceive the sound as much better than with the stock cable results from its energy and differentiation. I have not said it yet, but next to the Entreq the ordinary cable sounds withdrawn, a little behind. The new cable sounds more forward, stronger, fuller. Nothing is brightened or sharpened, sound attack is not over accented, and yet we get an impression that the standard cable waters down or “dissolves” the attack.
The HiFiMAN are not subtle headphones; they can pack a punch and show a large soundscape. The said cable, however, added sophistication to treble and midrange which previously seemed sufficient. Now I know that it was not. Excellent sound differentiation with that cable also allowed the sound stage to open up. The HE-500’s weakness is that they focus centrally shown details, such as singers’ voices, exactly in the middle. The Sennheisers show them as clear shapes, not just “straight in front of us”. The Swedish cable “opened them up” a little, i.e. it better distinguished the foreground from the background, presented it a little closer and larger. I am sure that is the result of a better resolution, better drawing of soundscape.

I have bought both reviewed cables. I’m not claiming they’re the best cables in the world. The Oyaide cable is yet to be reviewed and I hope it eventually will be. But the Entreq Konstantin 2010 is the first headphone cable that brought a definite improvement in my sound system and with my headphones, an improvement in sound and in the direction that suits me. It does not look as nice as the one provided with e.g. the Sennheisers, but it is handmade and therefore, to some extent, an exclusive product. The HiFiMANs clearly gain in the looks department because their stock cable is ugly and stiff. The Entreq will “pimp them up” nicely.


Little is known about the Entreq cable design. When I asked Per-Olof Friberg about it he weaseled out of answering, only saying that he’d worked on it a long time and that it’s lots of various small details. As he wrote in his introduction, he eliminated plastic and metal from around the conductors, relying instead on natural materials – wood and cotton. The cables arrive in wooden boxes and they look like a piece of craftsmanship. They are easy to handle and are not rigid – it is their advantage. They are however quite thick, much thicker than the stock cable because their cotton wrapping is rather loosely fitted to the wires.


  • CD player: Ancient Audio Lektor Air V-edition, review HERE
  • Phono preamplifier: RCM Audio Sensor Prelude IC, review HERE
  • Cartridges: Miyajima Laboratory SHILABE, review HERE), Miyajima Laboratory KANSUI, review HERE
  • Preamplifier: Ayon Audio Polaris III [Signature Version] with Re-generator Power Supply
  • Power amplifier: Soulution 710
  • Integrated amplifier/headphone amplifier: Leben CS300 XS Custom Version, review HERE
  • Loudspeakers: Harbeth M40.1 Domestic, review HERE
  • Headphones: Sennheiser HD800, AKG K701, Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro; 600 Ω version, review HERE, HERE, and HERE
  • Interconnect: CD-preamp: Acrolink Mexcel 7N-DA6300 (article HERE, preamp-power amp: Acrolink 8N-A2080III Evo, review HERE
  • Speaker cable: Tara Labs Omega Onyx, review HERE
  • Power cables AC (all equipment): Acrolink Mexcel 7N-PC9300
  • Power strip: Acoustic Revive RTP-4eu ULTIMATE
  • Stand: Base; under all components
  • Resonance control: Finite Elemente Ceraball under the CD, Audio Revive RAF-48 platform under the CD and preamplifier
  • Pro Audio Bono platform under Leben CS300