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Two other headsets that sounded interestingly enough to use interchangeably with the HD800 were the HE-500 and DT-770 Pro. The former brought more weight to the system yet maintained excellent dynamic differentiation. The sound was smooth, very selective and showed well-presented layers. It gained depth and the midrange had better saturation. But it was Beyerdynamics’ anniversary version which gave me a kind of golden mean. Dynamics were outstanding (perhaps better even than with the HD800) plus excellent selectivity and large staging (the HiFiMans tend to draw everything closer to the listener). This was a really excellent pairing.

Out of curiosity I dusted off my recently refurbished vintage Beyerdynamic DT-990 Pro and they were good too. Space was actually even larger but the upper midrange became slightly emphasized, something that's usually imperceptible but here was easy to identify. And so I stayed with the DT-770. That setup drew my attention with plenty of detail I had never heard before. It was a very interesting reading. In front of me—actually inside my head but listening a lot with headphones makes me think of recordings as though 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 interchangeably with my far costlier reference system. Whilst not equal (the Leben paired with the Sennheisers is still better at showing the color differences and has the more saturated sound), I gladly accepted these changes for the advantages I described above. The limited edition low-impedance Beyers had the volume knob barely above zero yet channel balance was perfect. I am quite sure that Ear Stream could release a special version of the amp whose gain was adapted for this particular type of load to expand useful volume range.


Conclusion. The Ear Stream Sonic Pearl amplifier is a good example of just how well made and refined in both design and sound can be the product from a tiny new manufacturer if the people behind it know what it’s all about - conveying emotions as the spirit of music. This task can be mastered in a variety of ways because ultimately the absolute sound is just an idea, not a real thing. Even the live sound is not what we get at home. It is of course an important reference point but only one of many and neither the final one nor the most important. Ultimately the value of a given audio product is defined by how much it helps us to get into the music and how much it helps the music to pull certain strings in us. In this respect the Sonic Pearl performs as you might expect from a mature product. This is not another me-too amp either in sonics or cosmetics. It is unique in every way. But it was not quite what I have in my reference system for better or worse. It lacked its fully saturated tube midrange, did not differentiate colors as well and exhibited insufficiently fleshy bass. While the latter may be individual taste, color differentiation is something objective. Even though this amplifier is unique, it still slightly averaged the nature of various recordings and presented them in a 'linearized' way': vibrant, illuminated and extremely dynamic. Yet not all records are like that and the Leben/Sennheiser pairing shows these differences significantly better.

It’s simply that you’ll need to pay about four times for that. If the Pearl’s sonic character matches your tastes, it will be difficult to beat in many areas regardless of price. However a listen with your favorite headphones is mandatory. And I cannot forget to again applaud its aesthetics which are simply fantastic! I do not know if it’s coincidence or not but the amplifier ideally matches the design and finish of the CanCans headphone stand from Klutz Design. These two make a natural match.


Review methodology. The Ear Stream Sonic Pearl amplifier was tested in an A/B comparison with both A and B known. Music samples were 2 minutes long but entire albums were also auditioned. The reference was the Leben CS-300 XS modified amplifier. I used Sennheiser HD800, AKG K701, HiFiMan HE-6 and HE-500,  Beyerdynamic DT-770 Pro Limited Edition 32Ω and vintage DT-990 Pro. The Sennheiser and HiFiMan headphones connected via Entreq Konstantin 2010 cables. The amplifier connected to two CD players, my Ancient Audio Lektor AIR V-edition and the Human Audio Libretto HD. I used Ear Stream’s own power cord and interconnect. The amplifier sat on its own feet placed on a wooden shelf from Base Audio’s BaseSolid VI rack.


Design. The Sonic Pearl is a headphone/preamplifier, the former its primary intended usage as confirmed by the Headphone Amplifier lettering on the front panel. Thus I reviewed it accordingly. The enclosure is made of thick aluminium panels joined in the inner corners to four aluminium blocks. The enclosure components are CNC machined for a perfect fit. Finish is black or white paint. What draws attention on the front panel is a large dome-shaped volume knob made from aluminium. A similar shape can be found in Meridian’s G Series but it remains an attractive design cue. The knob features a sizeable black ball half sunken into its surface as not an LED but simple setting indicator. The only illuminated indicator is a red miniature LED indicating power status. There of course is also a 6.3 mm headphone jack. The back sports a pair of stereo line input and output RCA. The output drives a power amplifier and is only active when the headphones are disconnected. An IEC mains socket features an integrated switch and fuse.


The interior confirmed what I learned in a conversation with Mr. Wyroba whilst he delivered his amp for the review. First the circuit is simplified to the maximum extent for both gain and power supply. It is the result of many years of research. Initially the circuit was very complex but that evolved over time. The gain stage is built on a single IC and the power supply is a fairly simple discrete cascaded voltage controller. Bridge rectification is by fast soft recovery diodes and there are also four rarely seen large Elna Tonerex filter capacitors just below their Cerafine units. Power comes from an averagely sized toroidal transformer. Unusually this bolts rigidly to the bottom panel. Normally it would be mechanically decoupled with a rubber washer. According to Mr. Wyroba the better the circuit design gets, the less there is need for any mechanical decoupling. In fact for this particular design he tried various washers of metal, glass, ceramic and wood. He observed that the sound was better with more rigid washers but best without any. Similarly the amplifier’s feet are four simple aluminium discs bolted rigidly to the bottom. A possible upgrade might be replacing those with ceramic ball bearing such as from Franc Audio Accessories or finite elemente but certainly not with rubber feet.

The power supply mounts on two separate universal PCBs (not custom board) with flying leads. The latter are solid core as Ear Stream firmly believes that stranded wire is characterized by adverse electromechanical effects. Grounding is by a single star-earthed layout. From the input connectors the signal proceeds over via long wires to a small ‘automotive type’ Alps potentiometer mounted on a solid aluminium block to the front panel. From there it goes to the gain stage board which features one Analog Devices opamp per channel (I could not determine the model number). These are surrounded by very good tantalum capacitors, more Elna and other types of capacitors carefully selected for their given task. After gain amplification the signal progresses to the non gold-plated headphone jack and from there to the output connectors. The line output is buffered by two capacitors totaling 20µF.
opinia @ highfidelity.pl
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