SALON AV: S.A.Lab Hercules SE. Integrated amplifier

Now it's time to talk about the second project by S.A.Lab, a Russian audio company. This test was especially enjoyable for it gave me an opportunity to compare a single-ended amp with a push-pull one under similar conditions and with the same music samples. The fairness was guaranteed because both schematics were realized on a no-compromise basis without regard for cost of labor intensity.

The recent test of Hercules Mk II, a three-block amplifier, compelled our readers to discuss the problem of whether it is necessary to spend much money on unit's looks or should the customer pay only for sound quality? Previously a similar debate concerned Starlingbox speakers. Somehow, a lot of people think that Russian brands are to manufacture only 'black boxes' or speakers finished with some cheap vinyl tape. This time I don't want to discuss even the notorious 'wife acceptance factor'. In my opinion a music connoisseur capable of spending $100 000 on an audio system has the right to make decisions concerning its design without taking advice from anyone. On the other hand it's sobering to recall the philosophical point referring to 'unity of form and content'. Developing a complex and expensive device from scratch designers naturally want to give their creature the looks in accordance with their tastes. Alexey Syomin, S.A.Lab's head and chief designer, ranks his Hercules amps not High End but State Of The Art. That's why he decorates them with genuine Carrara Marble brought from Italy and American walnut massif.

Integrated Hercules SE is almost similar to the pre amp of Hercules MK II lineup. They are mounted on the same chassis, have the same marble faceplate with circular display and the same wooden sidewalls. But there are some differences — e.g. volume control handle half-submerged into the top, rear acoustic posts and wooden nameplate with carved SE lettering.

«You surely know how much controversy was between the single-ended and push-pull schematic advocates but still there is no single opinion which one's better. And will never be either».

The final distinction is the fundamental one. SE doesn't mean 'Special Edition' as you may have thought, but 'Single Ended' pointing to a single-ended output stage. You surely know how much controversy was between the single-ended and push-pull schematic advocates but still there is no single opinion which one's better. And will never be either. Each design has inherent advantages and the choice is to be made on the basis of personal taste. Single-ended amps are much less efficient but they always work in Class A instead and don't have the so-called crossover distortion. Besides their sound is regarded as more musical thanks to domination of the second harmonic in its specter (in a balanced push-pull stage this harmonic's level is tiny). The push-puller drives demanding speakers better, but its distortions consist mainly of odd harmonics that many audiophiles consider discordant.

To achieve the output of 2 х 18 W (2 х 25 W max) each channel of Hercules SE utilizes four 6П20С beam tetrodes working as triodes. These tubes were manufactured in the USSR for sweep units of CRT TVs originally but turned out to be very reliable and musical and Alexey thinks himself very fortunate to make a large stock of them.

In a single-ended schematic the electric current flows through transformer's primary winding therefore designing this major unit is a serious engineering and partially esoteric problem. To avoid saturation the core has to have large cross-section therefore causes its turns' length increases. To prevent it a thicker wire must be used for winding and the transformer must be enlarged otherwise the winding won't fit inside it. Roughly the same thing happens with bass: to make it deeper it's necessary to use highly inductive winding (the inductance is directly proportional to the number of turns) but in this case transformer's inner capacitance also increases and upper frequencies are 'cut away'. Only an experienced engineer can break this cycle with priorities properly defined. Hercules SE utilizes transformers of custom architecture which will probably be patented. For the best alignment with load separate posts for 4Ω and 8Ω speakers are provided.

The input stages utilize Siemens C3g — unique pentodes designed in Germany for telecommunication purposes. This tube's grid is made of gold, its resource is immense and its noise floor is low without any microphone effect. Instead of C3gs a number of amps utilize Russian 6J4 metal cased tubes thoroughly selected from a large stock.

«In my opinion a music connoisseur capable of spending $100 000 on an audio system has the right to make decisions concerning its design without taking advice from anyone».

The listening test was conducted using the same source and speakers and in the same properly treated room that was used for listening to Hercules Mk II. First we connected Mark Levinson №512 CD/SACD Player then Studer A-807 Mk II tape recorder playing copies of master tapes made at 15 ips. Speakers were not too easy to drive by a single-ender — the same old 145-kilo Magico M3 with closed LF-loading.

Similar testing conditions invariably call for comparisons. The powerful Hercules threesome caused literally earth-shaking effect: first you were overwhelmed by an avalanche of sound but after a while it suddenly occurred to you that it was rigidly structured and each timbre sound was absolutely natural no matter what sound level you chose. In a big room with proper speakers an illusion of real orchestra presence will be easily achieved. Scope, dynamics and speed are the three pillars upon the sound stage rests.

Against these criteria the single-ended Hercules doesn't fall short as implicitly as one could expect judging by the difference in output. With speakers' sensitivity of 90 dB in a room of 70 m3 it created quite sufficient sound pressure. But the amp's strength lies on a different plane. It tries to seduce listeners with smooth delivery, with extraordinarily light and clear sound nevertheless exhibiting both handsome deep bass and detailed upper frequencies. The amp's temper is unique: it underlines not so much emotion or the power of sound as the meaning of it, its musical dimension. While playing classical music the transitions from one part to another acquire an amazingly substantial inner logic and beauty. You may not like the musical piece itself but its idea and the way it was realized by musicians is usually very appealing. Rock conquers you with its drive — not primitive 'pumped-up' energy but delicately stressed inner melodic content. Listening for instance to bass guitar parties, you pay attention not so much to attack, timber or reverb as to technique, texture and the guitar's ability to intertwine with other instruments. The hit is not deafening but thoroughly calculated and always bull's eye. Again there's not a single grain of cold analytics. Quite the opposite: the emotional impact is very effective and closely following the framework of a musical piece. Technically speaking it's this framework that puts emphasizes.

The soundstage is properly structured; on some tracks spaciousness is clearly demonstrated. Judging by precision and credibility of soundstage it's probably one of the best amplifiers I've ever listened to. It not only grants proper size to virtual sources but also provides their images a proper location in a 3-D space. Expertly recorded tracks e.g. those of small jazz combos turn the room into the birthplace of music in a truly holographic way.

«The input stages utilize Siemens C3g — unique pentodes designed in Germany for telecommunication purposes. This tube's grid is made of gold, its resource is immense and its noise floor is low without any microphone effect».

In other words Hercules SE is the amp for a cozy room with soft armchairs. It's made for enjoyment, for pleasant thoughts and carefree leisure. The only concern is to find records worthy of such a high-class device.

Rated output /max output: 18/25 W (4Ω) || THD: 0,03% || Size: 465 х 270 х 480 mm || Weight: 57 kilos || Price: 860 000 rubles

The editorial staff thanks «SoundProLab» for their help in conducting the audition.

CD/SACD
• Celine Dion, «All The Way… A Decade Of Song». SACD Sony 2004
• «Tutti! Orchestral Sampler». 24 bit HDCD Reference Recordings, 1997
• Jean Sibelius, «Concerto for Violin and Orchestra in D minor, op.47». Anne-Sophie Mutter and Staatskapelle Dresden. Deutsche Grammophon •••• GmbH, Dresden 1995.
• Noisia, «Split the Atom». 2 CD, Mau5trap, 2013

МАСТЕР-ЛЕНТЫ
• Ray Brown, "Live in Nagykanizsa",1998
• Freddie Mircury & Montserrat Caballe «Barcelona», 1987
• Michael Jackson «Thriller», 1982
• Rachmaninoff «Piano Concerto №3». Ashkenazy/Previn