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Integrated amplifier
Synergy Hi-Fi 6F3 

Price: 229 USD (together with a proprietary fuse)

Manufacturer: Synergy Hi-Fi

Dr Ningsheng Liu
tel: 852-66789172; fax: 852-27702803 


WWW: Synergy Hi-Fi

Text: Wojciech Pacuła
Photos: Wojciech Pacuła, Synergy Hi-Fi
Translation: Krzysztof Kalinkowski

The company Synergy Hi-Fi should already be known to the readers of “High Fidelity”. We tested the 300B tubes (fantastic!) of a brand owned by Synergy, Create Audio, and I also “filed a report” about the first contact with fuses manufactured by that company (while talking about the Leben CS-300 XS SP). However the appearance of an amplifier in their portfolio was something unexpected. That because Synergy Hi-Fi is not a manufacturer per se, it does not own any factory, but uses the wealth available in the country it comes from, China. There is a world of opportunity, not only in audio. You can manufacture there everything, and that at a lower cost than anywhere else. Actually there is already almost everything manufactured, what we see with so many different brands. So from that viewpoint Synergy Hi-Fi does not differ much from other companies, like Apple, Dell, NAD, Sony, Denon, Harman/Kardon, Cambridge Audio, Marantz, Arcam or even Krell – just to name a few (and not even mentioning the loudspeakers). Such business model bases on the customer designs the product, and the consignee manufactures it to the specification. But it often happens, that the consignee proposes a complete product, which is only modified by the customer to fit his needs and expectations. This is how it works today. Synergy Hi-Fi uses this model, but has the advantage above the competition from abroad, that being the ordering party it is located in the same country as the consignees. This results in better contact between the two parties, quicker reaction times to any changes, better quality control and lower prices.

This is the way the tubes are made for Synergy Hi-Fi, manufactured by a real tycoon in that area, the company Shuguang, the 6F3 amplifier by another specialist, the company APPJ, which prepares amplifiers for another Chinese brand, MiniWatt. Sam Telling wrote about that last company in his column in “Stereophile”, while reviewing the MiniWatt N3 amplifier. He wrote then, that the N3 might be the “smallest amplifier in the world” („Stereophile”, August 2010, Vol.33, No 8, p. 22). The 6F3 proves it is not. There is also another thing that needs putting it straight – Telling told, that the N3 was designed by Derek Shrek, the owner of MiniWatt. To straighten things out and explain everything I wrote to Dr. Ningsheng Liu, the representative of Synergy Hi-Fi, who responded: “Ha, ha, I know them – they tell everybody they design the amplifiers. But this is not true. N3 was designed and built by the company APPJ, which makes also the 6F3.” So that is it. However I think, that Derek Shek’s name was not mentioned by coincidence, because the split of responsibilities between the ordering party and consignee – the designer and manufacturer – can change. It seems that Mr. Shek was involved in designing an universal switching power supply, which does not need a big transformer and adjusts to input voltage between 100-230V. This is the role of MiniWatt as described by Telling in his article. How it is in reality I do not know for sure – and probably I will never know.

Having said that, I can finally get to the device itself. And the idea for it is brilliant in its simplicity. The amplifier is tiny, it fits in the palm of the hand. And with all that, it is splendidly made, from bent aluminum elements, anodized in one of the five possible colors: silver, gold, black, red and steel grey. The amplification path is fully tube one – each channel uses one 6F3, which was also used in the amplifier’s name. The tube is the size of an EL84, but inside there is one triode and one pentode, similar to the ELC82 or ECL86, which were used in many European amplifiers, like the Zero from Audio Note. The simplicity of the unit is almost iconic – we have only one RCA input, and the loudspeaker outputs are similar to the Naim ones – those are rather holes in the cabinet, accepting only banana plugs. And one volume knob. Bare and simple. There are no transformers visible – neither power or output ones.

Whenever possible I try to use for reviewing the same cables I use in the reference system, but this time it was not possible – the big plugs of the loudspeaker cables Tara Labs Onyx did not fit next to each other, and there was also no place for the RCA plugs. So I used the flat and handy cables from Ramses-II. Those are German cables manufactured by Kurt Hecker (one of the bosses of High End Society, the organizer of the Munich High End show), which I am preparing for the test. Those are expensive, so I still have the proper price difference of the tested product to the rest of the equipment used for the test, and their geometry and easy to use BFA plugs were ideal in this case. I’ll just add, that the cables were designed by Thomas-Michael Rudolph. I used for the test also the USB DAC/preamplifier Audinst HUD-mx1, which I tested for “Audio”. This is an incredible device, which dimensions, and design to use with a computer, seemed to me to be ideal for this purpose. I think that the 6F3 will usually work in computer based systems…


Discs used for testing:

  • Art Blakey Quartet, A Jazz Massage, Impulse!/Universal Music Japan, UCCI-9043, CD.
  • Barb Jungr, Love Me Tender, Linn Records, AKD 255, WAV 24/96; review SACD/HDCD HERE.
  • Basia, It’s That Girl Again, Koch Records/WHD Entertainment, Inc., IECP-10168, HQCD/FLAC.
  • Ben Heit Quartet, Magnetism, Acousence Records, ACO80108, 24/192, FLAC.
  • Diana Dors, Swingin’ Dors, Pye Records/Castle Music, CMFCD1554, CD/FLAC.
  • Diorama, Child of Entertainment, Accession Records, A 119, SP CD; review HERE.
  • Frank Sinatra, That’s Life, Reprise/Universal Music Company/Sinatra Society of Japan, UICY-94423, SHM-CD.
  • Helge Lion Trio, Hello Troll, Ozella Music, FLAC 24/96; review HERE.
  • Jean Michel Jarre, Magnetic Fields, Dreyfus/Epis/Sony Music, 488138 2, CD.
  • Judy Garland, Judy in Love, Capitol/Toshiba-EMI, TOCJ-9656, CD.
  • Kings of Leon, Only By The Night, RCA/BMJ Japan, BVCP-40058, CD.
  • Laurie Anderson, Homeland, Nonesuch, 524055-2, CD+DVD.
  • Martin L. Gore, Counterfeit e.p., Mute/Sire, 9 25980-2, CD.
  • Savage, Tonight, Extravaganza Publishing Srl/Klub80, CD001, 25th Anniversary Limited Edition, CD.

Japanese versions of the discs available on CD Japan

What can you expect from an amplifier, which has 2.5W at 8Ω? It depends on the amplifier – such output power is common for 2A3 tubes, and their users do not complain. But the case of the 6F3 is different. This is really a tiny amp, which can fit into a transformer cup of a 2A3 amp. This means, that a watt is not equal to a watt. Like I said in the introduction, 6F3 replaced the pre-power combo in my reference system, that costs around 250000zl. I know it looks silly, but this had to be the first step, as this is a part of the methodology of the tests – replace the reference element with the tested element. After such a change I usually deal with a catastrophe, a smaller or a bigger one, however inevitable, and the Chinese amplifier did not change anything from that. I did not expect it to be different, so it did not disappoint me. But I heard something, that can make this small tube amp an unusual alternative for budget amplifiers like Cambridge Audio Azur 340A SE, or 550A, NAD C515 (I didn’t hear the new C516 yet), or Denon PMA-510AE and PMA-710AE.

The sound of the 6F3 is clearly shaped, and we cannot talk about a well kept balance between the individual sound spectrum parts. It would be closest to what I heard from the Cambridge Audio Azur 340A SE and Denon PMA-510AE. I mean the withdrawal of the low frequencies, somewhere in the range of 100-400Hz. The tonal balance is thus shifted towards the midrange and treble. That was the reason to be very careful in choosing your loudspeakers with the amplifiers from the mentioned competition. In general you should think about warm loudspeakers, rather bass heavy. I am not talking that those were bad devices, nothing like that, but those are budget units, and the amount of compromises is bigger than higher on the pricelist.

The Chinese amplifier has its timbre shaped in a similar way. So also here the choice of loudspeakers will be key. But… This is a sound from a completely different level than that, of the mentioned competition, and in some aspects better than from more expensive units of the series. Even the NAD, so even in what it does, would not be able to match the tested component in some aspects. I am thinking now about the quality of the midrange and treble. All the mentioned transistor amplifiers, and we can add to those also products from Advance Acoustic, etc., are much more refined, than solid state gear from three or four years ago. Their “refinement” is based on a slight lowering of the level of the treble and shaping it in such a way, that it would not be so mechanical, “stiff”, or just “transitory”. I think that reclamation of the sound of inexpensive components was successful, and we can listen to music in a nice, comfortable way using them.

The Chinese amplifier uses to a full extent the fact, that the signal is amplified in tubes. It does nothing wrong – it does not warm the sound, does not mud anything, does not “forgive” everything about that, etc. But it shows a much richer palette of timbres, better transients and is much quicker – it is not about dynamics, about that in a moment – but about the fact, that it better differentiates the attack, the virtual sources, shading of dynamics. The treble and midrange are a bit softer, but in the good meaning of the sound, in the meaning that they are “not-stiff”, “not-hard” – a tube once heard will remind itself on many occasions, even if it would require some trade-offs.

6F3 sounds in a slightly soft, and despite that, very vivid way. The cymbals from discs, especially with good jazz, are nicely lit, but not underlined, or sharpened. This is actually one of the characteristics of this device – it does not sharpen anything, even in the slightest way. And this is a common issue with other budget amplifiers. The loss of weight in the lower registers forces a certain perception of sound. In this case it is the aim to show the sounds in a possibly clear way is not made through hardening of the attack and brightening, but through a better resolution. The tested amplifier, compared to competition, copes much better with various musical styles, sounding like a very big and strong amplifier. Yes – after the first shock, that something so small can work at all, we stand still, knowing, that something so small sounds so well. Because there is a dissonance between what we see and what we hear. In a normal room (up to 25m2) with good loudspeakers we will be able to play loud. This is the asset of tube amplifiers – the tubes go softly into clipping, not abrupt like transistors. We should not exaggerate of course, but there is no need to. In my room, with the Chario Academy Sonnet loudspeakers, the volume knob was usually at 1 o’clock.

Like I said before, in this case it is difficult to say about a preference to a certain kind of music, although electronics and rock sounded best. The last one was represented by Kigs of Leon and Diorama, while electronics was handled by Jean Michel Jarre and Savage. How well did it sound! There was no talking about big dynamics and here even the smallest transistor will be better. But the high dynamics and strong bass of inexpensive amplifiers will not translate into such a good sound as a whole. Interesting enough the range below 100Hz sounds quite strong. The first impression I had, when listening to jazz on the disc from the disc Art Blakey Quartet, and then vocals of Diana Dors, was that there is not enough bass. But it is not like that, it’s just, that the contrabass operates in the range of the bass withdrawal. With electronics, and with the brilliant disc Homeland Laurie Anderson, it could have been heard, that this tiny device can sound with a surprisingly full bass. Please check it yourself – I did not hear anything like that before!

The 6F3 sounds very well. Its sound is rather light – I told that already, but it can surprise with a low passage. There is no trace of brightening or sharpening, and the sound is rich in reverb. So it is worth to add a subwoofer to the set. And, different to the usual recommendation, it is best to filter the signal in the subwoofer (if it is possible). But even with small loudspeakers we will hear what I am talking about. But this is still the budget range, and despite my big sympathy to this phenomenon – because Synergy Hi-Fi is a phenomenon – I cannot omit the weaker sides of this solution. The dynamics in the macro scale is very limited, the sound stage is not very deep, and we cannot talk about discerning the individual sound sources, just as it happens in more expensive amplifiers. And yet the voices of the vocalists were clear, placed on the stage clearly, even if we could not talk about any “shape”, still the effect is at least good (acceptable). The coherence of the sound is also splendid – no solid state amplifier, at a comparable price, comes even close. Their makers try to achieve a comparable result by warming the sound, covering the flaws, but this is only a half-measure. In small systems, for example using a computer, the 6F3 will be something extraordinary – also for the acquaintances visiting us…


6F3 is a small stereo tube amplifier, working in Single-Ended Triode (SET) mode. And it is really small. Its construction is worth a full size, high level amplifier. The enclosure is made from bent aluminum elements, and the top cover from a sheet of aluminum. The chassis, the interior, is made from steel plates. The whole is finished with sanding and anodizing to one of the five colors. For testing we received the red version, which looks more like dark pink. On the front panel we have only one knob – a silver, chrome plated one, used for volume control. On the back we have one pair of RCA inputs and two pair of loudspeaker outputs. Those are not standard terminals, but accept only banana plugs, looking similar to the ones Naim uses (please have a look HERE). There is also a full size IEC power terminal with a mechanical power switch and a fuse. The tested amplifier was equipped with a Create Audio fuse (I wrote about them HERE). The tubes are mounted on the top to ceramic sockets with silver plated pins. The 6F3 tubes are Chinese make, NOS type. Those are actually two tubes in one – one triode and one pentode. In terms of construction the tubes are similar to ECL85/6GV8.

The circuit is mounted on two PCBs, mounted atop of each other, with distances. The top PCB has two small output capacitors and a part of the audio circuit. Amongst those there are also very nice RIFA coupling capacitors. The electrolytic capacitors are also nice, all coming from the Japanese Nichicon. The potentiometer is a miniature Alps one. On the bottom PCB, separated from the upper one with a shield, is the power supply. This is a proprietary solution from the company APPJ, which allows the power supply voltage to be between 100 and 240V AC. I did not know, that so many elements can be placed within such a small space. And with what style!

Technical data (according to manufacturer):  

  • tubes: triode/pentode 6F3
  • output power: 2.5W+2.5W/8Ω
  • frequency response: 30-40kHz (+/-1dB)
  • input sensitivity: 800mV
  • noise: < 0.6mV AC
  • power voltage: 100-240V AC
  • power consumption: 33W
  • input impedance: 10kΩ
  • output impedance: 16/8/6/4Ω (Japanese output transformers Z11-Ei48*24)
  • dimensions: 132mm (w) x 96mm (d) x (100+70)mm (h)
  • weight: 1.7kg
  • input: 1 x stereo RCA

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    • Phono preamplifier: RCM Audio Sensor Prelude IC (tested HERE)
    • Cartridges: Air Tight Supreme, tested HERE, Miyajima Laboratory Waza, tested HERE.
    • Preamplifier: Ayon Audio Polaris III with Re-generator Power Supply; version II tested HERE)
    • Power amplifier: Tenor Audio 175S, tested HERE and Soulution 710
    • Integrated amplifier/headphone amplifier: Leben CS300 XS Custom version (reviewed HERE)
    • Loudspeakers: Harpia Acoustics Dobermann (tested HERE)
    • Headphones: Sennheiser HD800, AKG K701, Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, 600&#160;&#8486; version (reviewed HERE, HERE, and HERE)
    • Interconnect: CD-preamp: Acrolink Mexcel 7N-DA6300, article HERE), preamp-power amp: Wireworld Platinum Eclipse
    • Speaker cable: Tara Labs Omega Onyx, tested HERE
    • Power cables AC (all equipment): Acrolink Mexcel 7N-PC9300
    • Power conditioning: Gigawatt PF-2 Filtering Power Strip (reviewed HERE)
    • Audio stand Base &#8211; under all components
    • Resonance control: Finite Elemente Ceraball under the CD (article HERE)
    • Pro Audio Bono platform under CD