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Headphone amplifier / linear preamplifier
Ear Stream

Price (in Poland): 5900 zł

Manufacturer: Ear Stream

Ear Stream Michał Wyroba
ul. Rogatka 13 | 31-425 Kraków | Poland
tel. 507 109 531 | e-mail:

Manufacturer's website:

Country of origin: Poland

Product delivered for test by : Ear Stream

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

Published: 1. October 2012, No. 101

“I am writing this as a fan of portal and a fledgling audio manufacturer. I have been interested in Hi-fi basically from primary school, when I assembled and ran first electronic circuits, including simple radios and acoustic amplifiers.”

So began the e-mail I found in my inbox last June. The author was Mr. Michał Wyroba who decided to turn his passion into a business (the entire letter can be read in the Hyde Park section HERE).
It is an amazing moment, the moment of taking from a hobby to a profession. For most manufacturers I know it’s a dream come true. And most of them started much like Mr. Wyroba, that is by taking their first major steps in the world of DIY.
He made his first designs for himself and shared his results with other DIY enthusiasts. The next step was to offer his products for sale. They were manufactured in very short series, housed in standard Hammond enclosures. In the words of Ear Stream owner, the point was to sell the best sound for the least money. He seems to have succeeded because after some time he felt like doing more. However, the transition from a hobby, i.e. DIY, to a marketable product is a big jump that caused many a good business to go down the tubes. One has to assume that all DIY products are a kind of ‘working prototypes’ in that there are no two, e.g., amplifiers looking and sounding the same. Each one is individual and unique. What is an advantage in the DIY world, in the world of “marketable” or “in-store” audio, or whatever else we call it, is unthinkable – they are flaws. The objective still is to sell the best product for the least money (at least I assume so), but there are other aspects that need to be taken into consideration: safety, reproducibility, customer service, attractive design, promotion, R & D funds, etc. Not to mention the additional costs such as dealer margins.
It seems that Ear Stream will not, at least for now, be concerned with the latter – the owner has opted for a direct sales model, calculating the final price of his products so that it contains only his own profit margins. What will come of this? I have no idea. Each of the two basic sales models, direct sale and distribution sale, has its advantages and disadvantages.

When I was arranging a meeting with Mr. Wyroba I did not know that. I only knew him from his e-mail. But I saw some potential which I hoped to explore. We agreed, therefore, that he would bring to me his Sonic Pearl headphone amplifier and his interconnect to connect it to my CD player.
I was expecting a lot, but when I saw the amp when I took it in my hand, I knew immediately that it landed. It is a fantastically well-made device with a really interesting design. There is little that can be changed about headphone amplifier design – it’s basically a volume knob, headphone jack, and possibly some switches and indicators. However, the Sonic Pearl is more than just another minor variant of the well-known design.
First of all we need mention its excellent, solid and very nice enclosure manufactured from thick aluminum sheets. I have kept for this review a white version of the amplifier, the hit of the last two seasons, but I have also seen a black colour version and I really liked it. The front panel naturally features a volume control knob but of an unusual shape, with a large indicator of volume level, resembling an oversized LED. On the both sides are a headphone jack socket and a tiny, red LED. That’s it. The whole is rounded off with very nice lettering, including the company’s logo. The amplifier is fully manufactured in Poland. When you get a chance to see it, you should understand my excitement.
All that, as it turns out, was made possible through teamwork:

  • Mr. Tomasz Szafarczyk (Mill-Tech Pro, Śleszowice 253, 34-210 Zembrzyce) is responsible for artistic design and enclosure manufacturing; the enclosure is made on multi-purpose CNC machines.
  • Ear Stream logo design and Sonic Pearl screen prints, cable labels and website layout is the work of Mr. Dominik Szrama; his designs can be seen HERE. As it turns out, one of its customers is another headphone specialist, White Bird Amplifications; we reviewed its Virtus-01 amplifier HERE .
  • Electronic circuit design and the final assembly of the Sonic Pearl, as well as Ear Stream cables confectioning is handled by Mr. Michał Wyroba.

The Sonic Pearl is not only a headphone amplifier, but also a linear preamplifier. It has only one input and one regulated output. The output is disconnected when the headphones are plugged into their socket.
The amplifier can be ordered in the following variants:

  • color – white, anthracite feet and lettering, amber or red LED,
  • color – charcoal and gold lettering, blue LED,
  • Pre out – disconnected by plugging in the headphones or constantly active,
  • preamp – gain equal (default) or any lower than 14 dB for headphones; the latter only with disconnected pre out.
For the review, along with the amplifier I also received two pairs of interconnects – the Signature for 1,599 PLN / 1 m and the Velocity, 999 PLN / 1 m. Their design is based on a ready-made cable, selected after careful listening tests, with a proprietary method of cable joining and soldering, terminated with excellent Neutrik RCA connectors (with a sliding ground connection). Mr. Wyroba strongly prefers solid-core cables, or alternatively Litz wire for shielded line level cables. He also brought a power cord of his own design which has been used to power the reviewed amplifier.


A selection of recordings used during auditions:

  • A Day at Jazz Spot 'Basie'. Selected by Shoji "Swifty" Sugawara, Stereo Sound Reference Record, SSRR6-7, SACD/CD (2011).
  • Audiofeels, Uncovered, Penguin Records, 5865033, CD (2009).
  • Depeche Mode, Abroken Frame, Mute Records Limited, DMCD2, Collectors Edition, SACD/CD+DVD (1982/2006).
  • Depeche Mode, Ultra, Mute Records Limited, DMCDX9, CD+DVD (1997/2007).
  • Ella Fitzgerald & Louis Armstrong, Ella and Louis, Verve/Lasting Impression Music, LIM UHD 045, UltraHD CD (1956/2011).
  • Enya, Shepherd Moons, Warner Music UK/Warner Music [Japan], WPCR-13299, SHM-CD (2009)
  • J.S Bach, Three Sonatas for Violoncello and Hapsihord, Janos Starker (wiolonczela), Zuzanna Růzičkova (klawesyn), Denon, COCO-70745, "Crest 1000", CD (2004).
  • Jean Michel Jarre, Magnetic Fields, Dreyfus Disques/Epic/Sony Music, 488138 2, CD (1981/1997).
  • Johann Sebastian Bach, Bach. Toccata and Fugue, dyr. Leopold Stokowski, Leopold Stokowski & His Symphony Orchestra, EMI Classic, TOCE-91077, "Best 100 Premium", HQCD (1960/2010).
  • Johann Sebastian Bach, Cello Suites, Richard Tunnicliffe, Linn Records, CKD 396, SACD/CD (2012).
  • Johann Sebastian Bach, Partitas, Preludes & Fugues, Glen Gould, Sony Classical, SM2K 52 597, "The Glen Gould Edition", 2 x SBM CD, (1993).
  • Józef Skrzek, "Pamiętnik Karoliny", Polskie Nagrania/Metal Mind Productions, MMP CD 0535 DG, CD (1978/2009).
  • King Crimson, In The Court of the Crimson King, Atlantic/Universal Music [Japan], UICE-9051, HDCD (1969/2004).
  • Komeda Quintet, Astigmatic, Polskie Nagrania Muza/Polskie Nagrania, PNCD 905, "Polish Jazz Vol. 5", CD (1966/2004).
  • Kraftwerk, Minimum-Maximum, Kling-Klang Produkt/EMI, 3349962, 2 x SACD/CD (2005).
  • Ludwig van Beethoven, Overtures, dyr. Sir Colin Davis, Symphonieorchester des Bayerischen Rundfunks, Sony Music Direct (Japan) TDGD-90013, "Esoteric 20th Anniversary", SACD/CD (1986/2007).
  • Me Myself And I, Takadum! Met Remixes, Creative Music, 001, 2 x CD (2012).
  • Portishead, Dummy, Go! Discs Limited/Universal Music [Japan], UICY-20164, SHM-CD (1994/2011).
  • The Beatles, Rubber Soul, Parlophone/Apple/Toshiba-EMI, TOCP-51116, CD (1965/1998).
  • The Eagles, Hotel California, Asylum Records/Warner Music Japan, WPCR-11936, CD (1976/2004).
Japanese editions are available from

The Sennheiser HD800 are my primary headphones. Together with the modified Leben CS-300 XS [Custom Version] they make a pair that has yet to be beaten. Other headphones that I have, or have heard, of course, also have their own advantages, and I cannot pass by the clarity and bass of the HiFiMAN HE-6 and the HE-500, the cream midrange of the AKG K701 or the extraordinary selectiveness of the Beyerdynamic DT990 Pro (Vintage) and the DT-770 Pro Limited Edition 32 Ohm. Nothing, however, brings it all together as well as the Sennheiser HD800. At least, that is my opinion.
The headphones, however, are only one side of the equation in which the other side is equally important – the headphone amplifier. And here, to be honest, I have not yet heard anything better than my Leben. Horribly expensive (after all modifications, with platforms and spacers it is about 20,000 PLN), with an expensive power cord, it is simply the best headphone amplifier I have ever heard. And while in case of headphones a few other models have showed some possible areas for improvement in the Sennheisers, none other amplifier offered anything better than the Leben. Maybe except mains hum which sometimes can be irritating on the Japanese amplifier paired with high-impedance headphones and which should not be there.
The Sonic Pearl is the first amplifier that shows two areas where the Leben can be improved – the pureness of treble and the sound attack. These two elements alone set the Polish amplifier apart and elevate it to a position where it stands heads and shoulders above the rest. For even though it is not a perfect amp and has its own sonic character, even though in the end I still choose my Leben, nevertheless, for about one third of the cost of the CS-300 XS [Custom Version] we get something that will guarantee comfortable listening.

Sonic Pearl with the Sennheiser HD800

I began listening to the Sonic Pearl paired with the trusted residents of my system, the Sennheiser HD800. From the first moment I could hear what was later only strengthened and confirmed by subsequent recordings – the pureness of treble, unprecedented sound attack and excellent, smooth upper midrange.
Never before, perhaps only in the most expensive speaker systems, have I heard such good piano. It is a notoriously difficult instrument, difficult to interpret by sound engineers. Each piano recording is actually an interpretation of what can be heard live. Should we choose a more direct sound, with less reflections, or how we set the balance between the left and the right hand, what about perspective, etc. – these are just a few choices that must be made by the sound engineer responsible for the recording. The Sonic Pearl interprets recordings in its own way. It shows the instrument in a fairly short perspective, as if we were sitting about 3-4 meters in front of the open lid. Not too many sound reflections, regardless of the recording I chose. Sound attack, the essence of piano sonic color and its expression, was fantastic.
They say that listening to a good, new piece of audio equipment or actually listening to the CD record on such device we discover something new, something we have not heard before. It is true, although in my case it happens more and more rarely. Not that I have heard it all, as I hope to discover new things for the rest of my life, but I no longer find these discoveries particularly moving. Maybe I’m jaded, who knows… Anyway, the Sonic Pearl for a moment gave me that thrill of excitement and I let it take me on a journey.

First of all, I listened to Glenn Gould’s recordings issued by Sony in the collection The Glen Gould Edition, a 1993 remaster using the SBM (Super Bit Mapping) process. That “invention” of Sony, designed to reduce quantization errors during conversion from the 20-bit resolution master tape to the 16-bit format required by the CD standard, seems to be no longer used by the company. In retrospect, I think that it was one of Sony’s better ideas.
The sound of the piano or the organ was smooth, velvety. It provided plenty information on the attack, the technique of playing. It did that without losing coherence which allowed combining all details into one overriding whole, into a musical composition. That is what the Polish amplifier showed flawlessly. It was clean. It was thick. It was natural. That piano really sounded, at least in the upper registers, in the way I have not heard before.
The same was true with other instruments – the violin, the cello, and the harpsichord. For example, J.S. Bach’s Three Sonatas for Violoncello and Harpsichord performed by Janos Starker (cello) and Susan Růžičková (harpsichord), recorded in the Prague home of the former, sounded truly captivating due to excellent presentation of micro-details, perfect connection between each phase of the sound. It was an attempt to recreate the live sound with its dynamics and vitality.

But these recordings also showed something else which – I assume – is manufacturer’s deliberate choice. What I mean is the setting of color accent.
At first glance, listening to electronic or rock music recordings may give an impression of somewhat light bass, of the accent being moved somewhere around 1 kHz. You can even get the impression that there is no bass, especially coming directly from the Leben.
And there is something to it. There “almost” is… Listening to Richard Strauss’ Also Sprach Zarathustra performed by Zubin Mehta and the Los Angeles Philharmonic, originally issued by Decca and remastered in K2HD by Winston Ma, you can hear excellent bass with great resolution. You can hear it not only in the famous opening, with a deep growl, but also in the end of Prelude when the only instruments are double basses. Similarly, listening to Enya’s albums, recently released on SHM-CD, you could appreciate what was going on in the bass department. The thing is that the whole was lacking the kind of saturation I am accustomed to.
It eventually boils down to the question of what, in our opinion, constitutes “the absolute sound.” The Sonic Pearl makes an attempt to reproduce the live sound, as if trying to skip the recording phase. Hence its outstanding clarity and dynamics. The problem is that music presentation at home is a different reality than the live event. It depends on the particular recording techniques and the very fact of sound registration, permanently changing the reality and making it a kind of “interpretation” of which I said before.
With the Polish amp we get everything very clean, very smooth and devoid of brightening. Usually, if bass is lacking and instead we are presented with lots of treble and upper midrange, it's simply a crude trick used to emphasize certain aspects of the sound. Here, the sound is very refined and its reception is not based on any tricks. It is, however, clearly a “set-up” sound.

What do I miss about it? Well, midrange and bass saturation. The Sonic Pearl makes all recordings sound “modern”, i.e. there is no patina of time, which – at least that’s how I see it – is quite clear. I, for instance, listening to Rubber Soul by The Beatles from the old 1998 remaster, an album issued by Toshiba-EMI, could not help the feeling that it sounds very similar to what the sound engineers attempted to achieve on the latest remaster of the band catalog from 2009 (see HERE). I noticed a similar thing with remasters of Polish music, such as Diary of Carolina by Józef Skrzek or albums from LIM – I already mentioned Also Sprach… but we can also add to this Ella and Louis by the pair Fitzgerald and Armstrong.
The thing is that compared to the Ear Stream amplifier, everything or nearly everything else sounds like a wet cloth. And, let me say it right away, I once already used that term in my review of the Harpia Acoustics Dobermann (New) speakers, which I used for a few years (see HERE.) It’s a very similar situation – the amplifier from my Krakow colleague is incredibly fast, open, clean, very well showing any jumps in dynamics, resembling what we know as the real, live sound.
Richer in experience with my current reference speakers, the Harbeth M40.1 Domestic (reviewed HERE), I must say that I personally miss some “body”, some saturation in the Ear Stream sound presentation. To some degree they are artifacts I mostly know from playback sound, not the live sound, but – I repeat – such is the reality of audio: the recorded presentation is different than the live event; they are two different worlds. The home presentation is thicker, more tangible, which is to compensate the lack of “visuals”. And it is no coincidence that this setup sounded extremely similar to the top electrostatic set from STAX, once reviewed by me (see HERE). Without a direct comparison it is difficult for me, however, to say something more specific about that similarity.

Sonic Pearl with the HiFiMAN HE-500 and Beyerdynamic DT-770 Pro Limited Edition 32 Ohm

In order to verify what I heard with the Sennheisers I sat down for testing with a bunch of other headphones I have. Pretty soon it became clear that the AKG K701 did not make a good match. The amplifier simply exposed their flaws - treble lacking definition, midrange that can sound a bit “plasticky” and the lack of low bass. They are still one of my favorite pairs of headphones and they sound great with many amplifiers. Nevertheless, they have their problems which in this case completely overshadowed their advantages.
I was very curious to see how such current- and voltage-efficient, clean-sounding amplifier will sound with the very demanding HiFiMAN HE-6 headphones (reviewed HERE). To drive them properly it was necessary to set the amplifier volume control near the maximum but I had no problem with that. The Sonic Pearl handled it easily and I could not hear any distortion indicating audio compression or clipping problems. Except that it was not quite the sound I was expecting, i.e. it was actually slightly worse than with the Sennheiser HD800. It was a bit dull and its color still bothered me, with not enough weighted bass.

Two other headsets that the amplifier sounded interestingly enough for me to use them interchangeably with the HD800, were the HiFiMAN HE-500 and the Beyerdynamic DT-770 Pro Limited Edition 32 Ohm. The former brought more weight to the system, while maintaining the excellent dynamics. The sound was smooth, very selective, with well-presented sound layers, differentiation of dynamics, etc. It gained some depth and midrange had better saturation.
But it was the anniversary version of Beyerdynamics that gave me some kind of “golden mean”. The dynamics was outstanding, perhaps even better than with the HD800, in addition to excellent selectivity and large space (the HiFiMANs tend to draw everything closer to the listener). That was a really good listen!
Out of curiosity, I blasted off my recently refurbished (see HERE) Beyerdynamic DT-990 Pro (Vintage) and they were good, too. Space was actually even larger except that upper midrange was slightly emphasized, which is usually imperceptible but here easy to pinpoint.
And so I stayed with the DT-770. The sound of that setup drew my attention with lots of details I had never heard before. It was a really interesting performance. In front of me (actually in my head, but listening a lot on headphones makes me think of recordings as if everything were in front of me) was a clear musical presentation, with quite well portrayed bass and outstanding dynamics. I could comfortably listen to this setup, interchangeably with my reference system. They were not equal; the Leben paired with the Sennheisers is still, in my opinion, better at showing the differences in color, it has a more saturated sound, but I gladly accepted these changes for the advantages of which I wrote above.
The limited edition of Beyer headphones I have is characterized by very low impedance (32 Ω), so the volume knob was barely off zero. Channel balance, however, was perfect. I am sure that Ear Stream is able to release a special version of the amp adapted for this type of load.


The Ear Stream Sonic Pearl amplifier is a good example of how well-made and refined, in terms of both its design and sound, may be a product from a new, tiny manufacturer, if the people behind it know what this is all about. And it is about conveying emotions, the spirit of music.
This can be achieved in a variety of ways because, ultimately, the "absolute sound" is an idea, not a real thing, and even the live sound is not what we get at home. It is of course an important reference point, but only one of many; neither the final one nor most important. Ultimately, the “value” of a given audio product is defined by how much it helps us get to the music and how it helps the music pull certain strings in us.
It is in this respect that the Sonic Pearl performs in the way you might expect from a mature, thought-out product. This is not another “me too!” kind of amp, either in terms of its sound or design. It is unique in every way.
But it is not quite what I have in my reference system – for better or for worse. It lacks fully saturated midrange and does not equally well differentiate color. There is not enough fleshy bass. While the latter may be a matter of individual taste, color differentiation is something objective. And although the reviewed amplifier is unique, it still slightly averages the nature of various recordings and presents them all in a similar way – vibrant, illuminated, extremely dynamic. But not all records are like that and the Leben with the Sennheisers show these differences significantly better.
It’s just that you need to pay about four times as much for that. So if the Pearl’s sonic character matches your taste it will be difficult to beat in many areas, regardless of the competition price. However, a listen with your particular headphones is necessary.
I cannot but mention again its aesthetics which is just fantastic! I do not know if it’s a coincidence or not, but the amplifier ideally matches the design and finish of the CanCans headphone stand from Klutz Design (reviewed HERE). They make a “natural” pair.

Testing methodology

The Ear Stream Sonic Pearl amplifier has been tested in an A-B comparison, with the A and B known. Music samples were 2 minutes long; whole albums were also auditioned. The point of reference was the Leben CS-300 XS [Custom Version] modified amplifier. The following headphones have been used during auditions: the Sennheiser HD800, the AKG K701, the HiFiMAN HE-6 and the HE-500, the Beyerdynamic DT-770 Pro Limited Edition 32 Ohm and the DT-990 Pro (Vintage). The Sennheiser and the HiFiMAN headphones were connected via the Entreq Konstantin 2010 cables (reviewed HERE).
During the testing the amplifier was connected to the two CD players – my Ancient Audio Lektor AIR V-edition and the Human Audio Libretto HD. I used a power cord and interconnect from Ear Stream. The amplifier sat on its own feet, placed on a wooden shelf of the BaseSolid VI [Custom Version] rack from Base Audio.


The Sonic Pearl is a headphone amplifier and a preamplifier, with the former being its primary usage, confirmed by the lettering on the front panel – “Headphone Amplifier”. It has been tested accordingly.
The enclosure is made of thick aluminum sheets, bolted in the corners to four aluminum blocks. The enclosure components are manufactured on CNC machines, hence the perfect fit. It is painted white (as in the reviewed unit) or black.
What draws our attention on the front panel is a large dome-shaped volume control knob made of aluminum. A similar shape can be found in other amplifiers, to mention the Meridian G Series, but it’s still an attractive design. The knob features a sizeable black ball, half-sunk in its surface. It is not a LED but simply a volume level indicator. The only active, i.e. illuminated indicator is a red miniature LED, indicating the power-on state. There is also a 6.3 mm headphone jack socket.
The back panel sports a pair of stereo line input and output RCA connectors. The output is used to drive a power amplifier and is only active when the headphones are disconnected. On plugging in the headphones into the socket on the front panel, the output line signal is disconnected. An EIC mains socket features an integrated switch and fuse.

The interior confirms what I learned in a conversation with Mr. Wyroba when he brought his amplifier for the review. Firstly, the circuit design is simplified to maximum – both the amplification stage and the power supply. It is the result of many years of research. Initially, the circuit design was very complicated but has evolved over time. The gain stage is built on a single IC and the power supply is a fairly simple, discrete voltage controller. Actually, there are two cascaded controllers. Bridge rectifier is built on fast-switching “soft recovery” diodes; there are also four large filter capacitors – rarely seen Elna TONEREX. In the Elna catalog they are listed just below the Cerafine. Power is provided by an averagely sized toroid transformer. Unlike common design practices, the transformer is bolted rigidly to the bottom panel. Normally, it is mechanically decoupled with e.g. a rubber washer. However, according to Mr. Wyroba the better the circuit design, the less need of any mechanical decoupling. In fact, for this particular design he tried various washers under the transformer, made of metal, glass, ceramic, and wood. He observed that the sound was better with more rigid washers and was best without any washer. Similarly, the amplifier’s feet are simply four aluminum discs bolted rigidly to the bottom of the enclosure. A possible upgrade may be replacing them with discs with ceramic ball bearing (such as Franc Audio Accessories, reviewed HERE, or finite elemente), but certainly not with rubber feet!

Power supply is mounted on two separate universal PCBs (they are not custom designed PCBs) with some connecting wires. All of them are solid-core (the owner of Ear Stream firmly believes that stranded wire is characterized by adverse electro-mechanic effects - each single wire interacts with surrounding wires). A single star earth point layout is used.
From the input connectors the signal goes via long wires to a small “automotive type” Alps potentiometer mounted on a solid aluminum block to the front panel. From there it goes to the gain stage PCB. It features two, one per channel, Analog Devices ICs (unfortunately, I could not determine the model number). They are surrounded by very good tantalum capacitors, more Elnas and some other types of capacitors, carefully selected for a given task.
After amplification, the signal is sent to the (non-gold plated) headphone jack socket and from there to the output connectors. The line output is coupled via two capacitors with a total capacity of 20 µF.


  • 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 PAB SE platform under Leben CS300 XS [Custom Version]; review HERE