MONO AND STEREO: S.A.Lab Black Knight Reference amplifier review

In Moscow, at the turn of November 2019, Alexey Syomin demonstrated a renewed product line from his S.A.Lab company. The lengthy two-day presentation included the demonstration of updated tube integrated Blackbird and Thunderbird amplifiers, threepiece Samson amplifier, 150W Black Night integrated (amplifier based on germanium solid-state devices,) a new ultimate cable line and even the S.A.Lab branded tubes with their logotype, that were manufactured according to S.A.Lab specs...

This unique opportunity has provided a chance to listen to all amplifiers in systems of various levels. Hercules, the S.A. Lab's was flagship was not completed at the time to make to the presentation, but it's still in development.

Among new products presented at this event the Black Knight Reference, a threecomponent state-of-the-art germanium semiconductor-based amplifier was premiered for the global launch.

Late in February, the S.A. Lab had also completed the dual-box(with separate power supply) phono preamplifier and headphone amplifier from the germanium line.

I was surprised neither by event invitation nor by the Black Knight Reference amplifier premiere because during more than ten years Alexey always keeps me informed about going on with his company (at least production-wise). Among the guests at this presentation was also Niccolo Fabi (Alexey Syomin's business partner) who's in charge of S.A.Lab representation and technical support in Europe.

I've extendedly listened to and tested integrated 150W Black Night germanium about two years ago and of course consequently knew already about that Alexey works on the Black Knight Reference, "The Big German" as he nicknamed it. I remember how he told me that the "400W germanium piece" will impress. In short, no such amp was ever built in the history of high-end audio. Yes, there are known germanium amps with 10W or even 15W, but here we're talking about 150W and immediately after that 400W!

What made Alexey use the technology of the past and mostly forgotten part as germanium transistors?

What is behind it? Is it a proximation, that something good can be made out of this particular electronic part or is the intuition of a highly experienced professional engineer, that feels how something meaningful is possible in advancing of the sound.

Maybe it's an expectation of certain reactions in the High-End market by introducing something so obscure? Or even settings to impress Guinness book of world records jury?

The last theory is highly unlikely as an objective one. So what does Germanium mean for S.A. Lab and how can it be connected with the established achievements?

Most people rely on the positive role and wisdom of the market that has to accumulate and implement all of the best and most progressive. Probably, this is the way of how things go. At the same time, it took under the look the subject matter it's the same "clever" industry that had minimized vacuum tube and vinyl records at one stage and woke them up from artificial coma years later...

The former, among many other things, lacked capacities of power density and the latter one was accepted as outdated in terms of limited dynamic range, surface noises, and user's inconvenience.

I see such comebacks from oblivion not so much as vigilantes of business, but more as a result of a basic human nature stubbornness. And it should be understood as such.

It seems that the germanium transistor didn't oblige to the same destiny as a tube — the power above all. Moreover, Germanium based devices are more difficult to be massproduced.

Today an amateur build Germanium parts can be found. An overwhelming majority, we're talking about the implementation of the old circuits. The corresponding stock items were absent on the market for more than half a century until "The German" of S.A. Lab appeared about two years ago.
S.A. Lab amplifiers based on germanium transistors are not following the old circuitry engineering. Germanium never followed the destiny of vinyl and tube gear, but it was highly interesting for S.A. Lab.

The authors of the usual reviews follow the traditional narrative and well-known techniques. The scarcity of information about Alexey Syomin is connected with his professional life, where he has spent most of his engineering years working for the military and later on for specific enterprises or laboratories connected with Soviet and later with Russian ministry of defense.

When asked if this work had anything to do with audio, Alexey smilingly said no.

However, one would think that such work has provided a great level of prerequisite experiences. The development of amplifier equipment took a considerable time of Alexey Syomin's life, but nothing was it made public until recently. According to his words, he always developed such kind of electronics almost as long as he remembers.

In the past, he showed interest in both transistors and tubes. As we can see, nowadays the tube equipment underlies the S.A. Lab catalog.

Alexey has explained to me why he prefers old tubes to new ones. He talks with regret about the disappearance of old technologies and industries. However, in last years he more often develops equipment on the basis of relatively new tubes frequently without being specifically of audiophile origin. For example, Soviet "television" 6p36c spectacularly functions in Samson and Hercules amplifiers. Though even in this case, the date of tubes manufacturing rarely dates after the 1970s.

According to Alexey, he "outgrew" direct heating triodes and this is testified by grandiose five-block complex Erato based on powerful triode GU-80 and three-block Ligeia based on British 14D13.

The transistor line of S.A.Lab includes a very interesting White Knight amplifier where the voltage was increased by the uniquely designed transformer ("we could patent this device") and current of the transistor's output stage. The special liquid compounds were applied for thermostabilization. The first generation White Knight partnered with TAD CR1 is one of the best amplifiers and amp/speaker combinations I've had a chance to listen to.

And now the Germanium. I've heard about germanium transistor from Alexey nearly three years ago. He told me... "I am making amplifier based on Germanium". But we didn't follow up on the subject matter. He told me that when the amp will ver ready, I'll be invited to the listening and then we can talk father.

I asked Alexey Syomin what he found in Germanium transistor that is so good, merely from a technological point of view and especially what was he thought that he can achieve sound-wise.

«Actually germanium is much better fitted to operate with sound signal than silicon. The movement of carriers is much higher in it. If in the case of silicon, it acts in two ways... Now is open and then it is closed. With Germanium, it is permanently open. However, to get competitive power it's is quite difficult. To prevent the breakdown of certain isolation mandatory between transitions. And if in case of silicon to make it there is no problem, in case of Germanium such task always presented a problem».

Alexey is right in his assessment of Germanium advantages. Indeed, Germanium as a chemical element (the 32d one in the Periodic Table) by far excels silicon by the sheer movement of electrons throughout the space and it also by extended the length of electron's free path in average up to three times.

Also, it has a lesser width of the forbidden band. The analysis of voltage drop at p-n and n-p junctions demonstrates that Germanium proves itself as a better conductor than silicon. Therefore, the Germanium amplification stage has lesser energy losses. Also, Germanium has significantly lower switching distortions that are resolved with silicon only by transferring output stage to Class A with correspondingly high costs. A considerable investment was needed to research Germanium projects that are conditioned by many other factors.

From some time, the world market began to feel the deficiency of Germanium transistors due to the stoppage of their manufacturing without recommencing the similarity to the tubes.

The real reason was different. There was no demand, so no offerings and vice versa. In Russia, in contrast to the rest of the world, Germanium transistors of particular series continued to be manufactured down to the turn of millennia. Alexey managed to purchase a very large batch of Soviet 1T813 (20 000 pieces) manufactured in the last fifteen years of the last century. With such stock, he could really handpick and selected properly matching pairs needed for his "Germans".

Alexey further speaks about the history of transistor circuitry and the causes of manufacturing transition from Germanium to silicon. "It is quite understandable why Germanium was succeeded by silicon that began to prevail from the end of the 1960s. The silicon transistors are by far more reliable and easy to produce. Furthermore, they can provide the power that is more than adequate for modern requirements. There was no Germanium amplifier with power exceeding 100W. Though it is quite possible that there were certain particular more powerful items for stage performance.

Certain high frequency and microwave devices were manufactured along with Germanium audio devices. However, the transistors themselves were far from satisfactory, including the sound. At 20 kilohertz, their amplification came nearer to 1. As regards working temperature, silicon keeps functionality when heating up to 150oC and 100oC as it's their working temperature. Whereas Germanium goes topsy-turvy to garbage pail already at 80oC. And for silicon, the temperature of 80oC is what the needed optimum".

«In the old days, there were no high-voltage Germanium transistors. Though both theoretically and sound-wise the Germanium suits better to home audio. All its advantages are practically smoothed over by its capriciousness. So, the history of Germanium is not so much history of schematics as the history of thermodynamics and search of modes for maintenance of functionality for this element. The Germanium transistor requires a very large radiator and special conditioning to provide working temperature stabilization. Initially, I didn't understand it enough. For a long time, I couldn't manage to restrain its disposition and to make thermal and current dependencies and relations workable. So, I had to look for approaches for thermostabilization and limitation of current driver and output stage transistors».

The initial tuning of the Black Night scheme (integrated in the beginning) took more than 2 years. As Alexey admitted this work mostly consisted of disappointments as "none of our amplifiers worked for a long time and withing such difficulties".

Initially, S.A. Lab demonstrated its Germanium integrated amplifier Black Night of 50W. The next two generations of this amplifier added 50W compared to the previous one. Nowadays, the company portfolio offers Black Night integrated with the output power of 150W at 4 Ohms.

While designing Black Night amplifier Alexey Syomin departed from what was achieved in developing "The small German". According to him, "these amplifiers have very similar circuits".

The output stages and drivers of both models are based on Soviet 1T813 Germanium transistors. The amplifiers lack global negative feedback and this is a unique principle and feature of Alexey Syomin.

The more powerful Black Knight Reference uses more output transistors thus resulting in the development of the bulkier plates, heat sinks and power supplies and ultimately in the adoption of three-chassis architecture.

The implementation of the Germanium series of circlotron scheme in S.A. Lab amplifiers became extremely important. Alexey assumes that this scheme matches the Gest germanium transistor with its specific equal admittance on p-n-p junctions.

«I optimized circlotron to receive specific sound quality. This is the most complicated and cost-based case though the most perspective one. The circlotron without global negative feedback permits transistor scheme to sound at the very least not worse than tube one. It is impossible to contest the fact that transistors are never 100% complementary. Complimentary pairs simply don't exist and in the case of circlotron, the signal parts are always complementary because output stage functions on bridge mode. However, the output cascade of circlotron requires two independent main power supplies. Overall, the Black Knight Reference monoblock has four power supplies subjecting to the driver power supply».

Alexey told me that he had to select Germanium transistors 1T813 based on their parameters in the most thorough way. "The spread is monstrous even within the scope of one single batch. The amplification coefficient ranges from 20 to 150! There are no such problems with silicon since silicon transistors are barely like nuts or… twins" The special precision instrument produced in the USSR was purchased for selecting of the devices.

Thus, the output and driver stages of "The Big German" monoblocks are based on 1Т813 Germanium transistor. The Black Knight Reference amplifier is produced completely on the basis of Germanium transistors. Specifically, rectifiers in power supplies are implemented on the basis of D305 diodes.

The monoblock power circuit includes capacitors with a total capacity of 80 000 mkF. The electrolytes and special bridging film capacitors 4x470 mkF are produced by S.A. Lab and settled after the stabilizers. They are fixed on brackets made of artificial stone.

The designer provided multilevel control of thermal parameters to support optimal modes of operation of schemes and also for the unconditional functionality and reliability of the amplifiers.

The massive heat sinks are developed for the output stage and power supply. While the outfit is functioning as the controllers and permanently monitor the temperature of output transistors if the heat becomes higher than 35oС, the noiseless coolers are switched on. Each monoblock includes five such coolers: two for output cascade, two for power supply and one for a driver.

The temperature of the amplifier's power supply parts and can be controlled visually and are presented by two digital indicators placed on the plates inside of the Rectifiers on germanium diodes The heat sinks are removeable and tipping-up monoblock. Apparently, this option is done only for convenient tuning-up and control of the schemes and hence it has no consumer value. The dropping-out plates of amplifier and power supply with relevant cooling radiators are developed for the same purpose.

The protective devices for four power supplies are placed in the compact block with a company logo. The outage of safety devices is indicated by an LED glow.

The scheme of soft start ensures gradual stabilization of the voltage. The amplifier is fully operational approximately after 50 seconds after switching on and that indicated on the display.

The principal characteristic of S.A. Lab strategy is that with the exception of integrated amplifiers, other models are manufactured in three-chassis (rarely in two-block) layout as a kit composed of preamplifier and monoblocs. S.A. Lab, during all periods of its existence, proposed a very limited number of single power amplifiers and preamplifiers with the exception of phono stages and preamplifiers with DACs. S.A. Lab's owner implements this principle of his own in the equipment of various price levels. Such are grandiose Ligeia, five-block Erato and Muse's Whisper and also Hercules, Samson, and even inexpensive Lilt. Such is Black Night Reference too. It is clear that an engineer who chooses this way takes upon oneself to work on the ideal harmonization of all amplifier sections without shifting it off to the consumer.

From this point of view, the Black Night Reference preamplifier is an integral component of the complex structure. And of course, it is totally Germanium based. The preamplifier functions on the basis of several Germanium transistors from the Soviet and Russian production.

The transformer presented here was custom designed and produced by S.A. Lab especially for this particular project, providing amplifies voltage with needed amplitude.

«Theoretically, the transformer is a totally linear device. It manufactured manually hence this device is so expensive. But as far as we produce basic components to manufacture a transformer is not a big deal».

At the input and output, there are balanced transformers. The signal outputs are unbridged and each has a separate buffer. The sound volume control is implemented on the basis of tantalum resistors.

The preamplifier has five linear inputs (three RCA and two XLR) and also three outputs (two XLR and RCA). There is an indicator of the operating time counter. The power of the preamplifier and monoblocks can be switched on manually or by a trigger. The monoblocks receive a signal on the balanced sockets XLR. There are two pairs of speakers terminals designed and manufactured by S.A. Lab.

The visual appearance of "Knights" fully conforms concepts of Top End class equipment. The traits of design are glassed stone colored with Ferrari line enamel of, grids of stainless steel, high-quality leather with stitching and trademark eye-like display on monoblocs front panels. The amplifiers can be manufactured in any color and not just black, but the amplifier keeps its initial name — the Black Knight.

In order to monoblocks to be moved more conveniently (275 kg each) special platform with casters is provided (covered with leather). The wheels can be removed and replaced by isolating parts.

The amplifier, as compared with the monoblocs staggering with their mighty stature, looks a bit lonely resembling a neat little house at the footing of two towers.

The Black Knight Reference, like all other S.A.Lab products, are fully assembled at the company factory in the Moscow region. A number of such major elements as power transformers and certain capacitors are produced by the company itself. The output transformers of all-tube amplifiers are designed and manufactured only by S.A. Lab.

I had an opportunity to explore carefully the sound performance of S.A. Lab Black Knight Reference during long-lasting listening sessions prior and after the presentation mentioned above. Additionally, I've had a chance to listened to the amplifier extensively at the S.A. Lab's official listening room, including the prototype stage.

For the presentation of Black Knight Reference in the Moscow salon Note+, the hightop level system was assembled that included Kronos Sparta turntable with Kronos Helena arm and Lyra Etna cartridge, Studer A 820 tape-recorder and Moon 750D CD player The loudspeakers were ProAc Carbon Pro Eight. The record-player was assisted by a two-block S.A. Lab phono stage from the Germanium line (demonstrated before Moscow premiere at the end of February 2020) and step-up transformer S.A. Lab Step-Up Black Edition.

Being a musician myself, I deal with the music most part of my life. When more than forty years ago I began to listen to music recordings — initially using equipment made in the Soviet Union and later, as far as being involved into audio expertise, using Hi-Fi of various levels, I was aware that I am forced to listen to audio equipment with a kind of different ears comparing artificial sounding with natural sound. These differences I've kept in aural memory that and I can firmly be distinguished when music is properly reproduced properly. With time my sense to distinguish these two becomes even more profound. In a sense, it becomes a switching principle of comparing.

I also pay a lot of attention to the emotional experiencing purely audiophile quality that is specific to the audio equipment listening and consists of analyzing the purely sound aspects. When listening to the music of the concert the rendering is present only in the slightest degree or is absent at all.

My most powerful impressions of sound relate to those moments when I had no need "to switch" my hearing and when insignificance of purely audiophile feelings fused with a plenitude of musical ones. The listening of S.A. Lab Black Knight Reference is one of such occurrences. The amplifier has a unique musical potential, even for High-End equipment, being not only an audio component but an instrument of converting recorded material into music almost indistinguishable from performed live by a number of its most important components.

I have to clarify what is hidden behind this "almost". By no means, I don't idealize livesounding that quite often is frankly indifferent. The musicians can be not performing at their best and the musical instruments can be not "Amati" or "Blüthner" at all or even simply untuned and acoustics in the concert hall can be no gem and place for listening can be inconvenient and mood can be lousy and moon in the wrong phase...

Such musical recording should be perceived as a sort of art seeking to create perfect sounding with the ideal balance of the components. This sound is created by sound engineer/producer and the involvement of musicians into this process in many cases is limited by the performance of musical compositions. The sound record will be always inferior to live performance only in one thing — the last one is momentary and inimitable. The emotional experience can be unique and momentary also while listening to records by means of audio equipment of such a class as S.A.Lab Black Knight Reference.

The affirmation "you hear the music such as it was heard by musicians in recording studio or concert hall" is, to put it mildly, incorrect. We hear it such as it was heard by sound engineer/producer. And he hears, to be frank, the bulk of equipment packed in the recording room. Thereby, the recording contains certain music and the task of audio equipment is to reveal exactly what music contained in it and how much of it is there...
The Black Knight Reference, while playing back various recordings supported by matching system partners, every time produced from the sound the "ore", the grains of musical truth, that touched and excited me in a real way and not simply tickled audiophile receptors.

While listening to opera airs performed by Renée Fleming or Luciano Pavarotti (Hemiolia Records tapes ) I didn't know how actually Fleming and Pavarotti sang during a recording session (by the way I never heard them in live performance), how orchestra played and exactly what sound was brought by studio monitors to ears of the producer. However, I perceived the voices of interpreters as real ones. The sounding was spacefull, warm and heartfelt...

The sound of Black Knight Reference has some intricate quality, almost irrespective of reproduced music, that makes these amplifiers very different from the multitude of the tube and transistor amps.

The first that crosses one's mind and connected this special attitude is the functionality of Germanium transistors in fortunately found makeup.

It is obvious Alexey Syomin and his team efforts of painstaking research of the approaches to germanium are the very results. This sonic quality can be appreciated by any listener even without an audiophile background.

Such sound can be appreciated and perceived as straight away as genuine and devoid of artificiality. This specific quality is intimately related to the integrated Black Knight that I listened many times both separately and jointly with the Black Knight Reference.

The special feature of music perception is that prior to when musical sounds, rhythms, timbres, consonances, and spatial patterns begin to take shapes of completed musical thoughts and images the sound is perceived as complex acoustic energy stirring up one or another hearing sensation and various emotional responses.

S.A.Lab "Germans" sound quality felt most natural due to evaluation listenings. The amps establish so to say a friendly acoustical environment.

It is acoustically "ecological". Even more, it excites emotions similar to those one feels admiring the scenery, beautiful architecture, nice face or anything else really sweet...

The S.A. Lab Black Knight Reference's 400W let the moments of musical culminations fulfilled providing the dynamic relief when it was needed to be expressed in all of its magnitudes. The muscly power of amplifiers reflects the spirit of their name — Hercules. The extensive and gradual intensification of sound in Ravel's "Bolero" comes to the only tone modulation in score and culmination of powerful fortissimo at the end of musical composition. This very dramatic point in the presentation by "German" was 100% convincing. Just as a very quiet beginning when dry drumming of the snare drum is superimposed on the underlay of absolute silence.

The Black Knight Reference possesses all arsenal of sound instruments. Dies Irae from Verdi's "Requiem" was presented in such a way that though musical plasma literary spread out in the room. The dense orchestral and choral have issued their painful mood throughout the large-caliber kettledrum fougasses. The whole mood corresponded to the visions reflections of the Last Judgment. And Verdi simply excels.

Immediately after, In Paradisium from "Requiem" by another composer, Gabriel Fauré, was presented most exquisitely. Lace or filigree: against the background of the wavy figures in the orchestra, the sound of choir flowed like an enchanting paradisiacal light from Heaven.

When evaluating and describing the audio component, everyone will most likely want to listen to music he likes and prefers. Authors of the audio reviews are not an exclusion. Arturo Benedetti Michelangeli plays Debussy: Préludes Book 1 (1978)

Among other things, I've listened to piano music on vinyl: Arturo Benedetti Michelangeli performs preludes by Claude Debussy from the first book, Glen Gould plays Goldberg- Variationen by J.S. Bach (1955 recording), Vladimir Horowitz interpreters pieces of Robert Schumann ("The Last Concert in Hamburg") and Emil Gilels performing the 3d Piano Concert by Ludwig van Beethoven with the Cleveland Symphonic Orchestra conducted by George Szell.

Except for the formal presentation of the piano, everything is different: music, maestros of fingerboards, pianos, time of recording, sound engineers, artistic spaces... Every single time I've heard the system with Black Knight Reference average out nothing reduces nothing to a common denominator and deduces no average temperature over the hospital.

The amplifiers reproduced music with its genuine aesthetic charge. Not only the sound of different pianos were easily distinguished, but also the individual sound of Michelangeli (the art of chiaroscuro and amazing touch subtlety), of Gould (pervasive expression), of Horowitz (unique Hamburg Steinway the "last romantic" performed in concerts and recorded during more than half a century) and of Gilels (inimitable golden sound, wisdom, generosity, and perfection of interpretation)...

The absence of sound sketchiness is the most precious quality of Black Knight Reference that became apparent in the presentation of various music.

The amplifier demonstrated its ability to transmit the broadest timbre palette in all frequency registers and to form diverse unique acoustic spaces, including vast dynamic resources and perfect control of lower case while the records from excellent Musikproduktion Dabringhaus und Grimm organ series were played back. The records themselves and how they sounded was real festivity for organ music lovers.

The sounding of records Meet You at Jazz Corner of the World of Art Blakey and Jazz Messengers combo is quite in the spirit of half-professional club recordings. The Black Knight Reference transmitted with ease natural and emotionally charged atmosphere that filled the New York Club Black Birdland on September 14, 1960; how the musicians freely moved around the scene regarding the microphones.

From time to time the sound became lighter or somehow receded into the shade; all this non-studio feeling, a certain sketchy and uneven sound that one can't find in studio albums that quite often sound too ordered and even a bit sterile. Evidently, the discs Meet You At Jazz Corner of the World are considered as one of the best live recordings in the Jazz Messengers' discography.

Was it worth toiling non-simple engineering tasks to implement Germanium idea in the real audio components? The reply with all its evidence follows from what has been said above. The S.A. Lab Black Knight Reference is a highly complex amplifier of the highest engineering level that is determined not only by the very fact of the Germanium transistors application but also due to its unprecedented high power. This true top-class product embraces the impeccable quality of implementation down to the smallest details.

I would like to mention one more time about the common DNA of the Black Knight Reference and Black Knight integrated amplifiers. The last one costs more 10 times less than Reference and it should interest those who wish to experience the magic sound of S.A.Lab's "Germans". If the very high price of Black Knight Reference feels to be competitive then the price of the small "German" seems to be attractive.

Of course, everything was ultimately forged to deliver the best possible sound. And with S.A.Lab's "Germans" nobody needs to strain one's ear to decipher the outstanding musicality of the amplifiers.

The purpose of High-End audio always was to reach the sonic illusion in the presence of music and in the absence of hardware in the listening room. Alexey Syomin proposed exceptionally convincing solution of this task shaped in the form of grandiose Black Knight Reference that can recreate live music, nothing but Music, following the very essence of what the originally recorded music on the record contains.

--
Artem Avatinian
Translated from Russian by Vasiliy Nechaev

Price: 300 000 EUR

• Class AB Push-Pull amplifier
• Output power — 400 W (4 Ohm)
• Frequency response — 2 – 200 000 Hz
• Nominal sensitivity — 800 mV
• Input impedance (RCA/XLR) — 47/25 kOhm
• Signal-to-noise ratio — 103 dB
• THD — 0,05% (50 W, 4 Ohm, 1 kHz)
• Power consumption (max.) — 460 VA
• Output power (4/8 ohm), watt — 400/200
• Dimensions of pre-amplifier, mm — 150 х 480 х 450
• Dimensions of monobloc, mm — 1050 х 440 х 880
• Preamplifier weight, kg — 21
• Monoblock weight, kg — 275