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Audio Space Reference-1 Flatship Mono Block
Audio Space Reference-1 Flagship Vacuum Tube Mono-Block Power Amplifier

(Audiotechnique Vol. 269, p. 98-105)

It's nearly 20 years since Top International Electronic Ltd. (Audio Space) established in 1986. Mr. Lau, the founder, was formally an engineer of Hong Lik International as well as an audiophile. In early days, the main line of the company was the production of audio visual and karaoke equipment. It has manufactured so many cheap but high quality products which favored by majority of audiophiles since it began to massively produce electron tube amplifiers in 1990. It is no doubt that Audio Space is the most successful local manufacturer of acoustic equipment. The company has manufactured numerous representative products in the past ten years, Among them, there were: Mini 1997 and Mini 1998, the most economical mini integrated vacuum tube amplifier in the world, economical pre-amplifier Line 3.1 and AS-9 MKIII Mono Block with excellent sound, DAC-1US digital-analogue converter, the first amplifier of dual tube and transistor with increased frequency of 24Bit192Hz in the world as well as the Duntonic Series which has recently won favors from many audiophiles. It is really innumerable. In order to further upgrade Audio Space's international status and put into practice Boss Liu's idea of Hi-end, director has recently developed the mono block power amplifier, Reference 1 after so many years' design and research. Beatle and Simon have always expressed their identification with the idea and products of Audio Space through their action. They will consistently buy Audio Space's products just as in the past. It is natural that every people are itching to have a try on the very sight of the dominant amplifier of palace grade manufactured by Audio Space.

The Reference stroke its pose on the stage early in 'Hong Kong Advanced Audio Visual Exhibition" held in last august. Its delicate appearance won much praises from audiophile, even though they had not witnessed its performance. Reference 1 was formally put in market in the end of the year. Its selling price at the time was 138, 000 Hong Kong dollars which was very expensive. Just as the old saying goes 'True gold does not fear fire", around 20 sets of Reference 1 were sold in a short period of time. Even samples prepared for CES exhibition in U.S.A were bought off by American audiophiles who were well known for their fault finding. At that time, the demand far exceeded the supply. It was really a rare thing at the time when the global economy was in depression. However, Audio Space lived up to this goal.

The early products of Audio Space were manufactured based on modification to conventional circuitry of well-known foreign brands, for example, the early Houston 7 front amplifier and Houston 9 back amplifier favored by most of audiophiles as well as the present Line 3.1 pre-amplifier and AS-9MKIII post-amplifier. At the same time, Audio Space also dedicated to develop its own products. Based on their own design, Audio Space's engineer developed the first AS-9062 26W amplifier with "Tube King 300B" driving "Tube Queen 845" and 50W AS-8530, the single-end class A split amplifier with 300B driving 805 tube. This event caused great repercussion in Hi-fi industry. These two models of power amplifier have been regarded as the amplifiers for collection by many experienced audiophiles. From then on, Audio Space gradually built up its own style and status in the world. If a Hi-fi manufacturer wants to find a foothold in the audio market and set up its reputation, it must have its own leading product as basis, for instance, B&W 800 Series and KW series of Musical Fidelity. It was probably that these were not manufactured for the sake of making money. In addition to wining honor for company, it was also developed for the purpose of realizing designers' design and conception. It was a worshipful spirit of persistence. Director Lau and engineers wracked their mind in design this Reference 1, which took them several years' time. They even took time to study design drawings when they were in the car, ferry and on the plane. They even worked to the extent of forgetting food and sleep. As it was Audio Space's leading product, therefore even a bit of fault was not allowed. On the other hand, as required by work, Director Lau frequently went on errands or went to other places for visit and exhibition; therefore, he naturally had more opportunities to get to know some well-know foreign brands. As a result, the scope of reference was expanded which was a great help to the design of Reference 1. At the same time, Director also made some corrections to the wrong sayings widely spread among the tube fans and DIY fanciers. According to this saying, an excellent amplifier which is capable of producing excellent sound effect may not need high quality material and tube. If the design of a high quality amplifier is simple as this saying, then it is a profanity to the wisdom of designers. If you try to equip a cool amplifier with Jensen oil immersed silver capacitor or M-cap oil immersed silver capacitor, it is no doubt that the sound will be terrible rather than astonishing. The used material, circuitry and selected tube of an amplifier are judged in terms of deployment. This mainly depended on the skill of attunement. For this purpose, the power source and output transformer of Reference 1 was manually rolled with special shielded material and advanced technology. Electrolytic capacitor which was usually known as "Pond", the soul of the tube amplifier. As the suitable electrolytic capacitor was not available in the market, Director Lau had to manufacture the 4 "Pond", Magic Power Cap suitable for Reference 1 with material imported from Germany. All of amplifiers without exception subjected to vacuum treatment and packing, and therefore were able to bear the impact of 2000v high voltage. This type of amplifier was suitable for 50 years' consistent use, and therefore was durable and reliable.

Any one of 4 "Pond" selected is without exception based on the precise calculation. Its advantage lies in the speedy charge and continuous discharge. Furthermore, its special structure can effectively increase the differential ability at high frequency mode. Due to complicated manufacturing procedures, the cost for each electrolytic capacitor is over 2000 Hong Kong dollars. In view of this reason, the selling price of Reference 1 is reasonable.
Material deployment selection

As to a tube amplifier, the hum sound is a kind of sound which is difficult to deal with. In order to solve this problem and prevent disturbance between elements and from exterior RF, the inside face of cast steel shell of Reference One was galvanized with special material for shielding. Later, I was informed that Audio Space was the first manufacturer in the world adopting expensive cast steel for amplifier shells. This filled me with more respect for the creative spirit of Audio Space.

Director Lau was meticulous in selecting elements suitable for Reference One. The core of Reference One was assembled with various kinds of expensive elements such as M-Cap Oil, M-Cap Supreme and MIT RTX. The selected resistance was RMG resistance. The attunement for Reference One always took a long time. Just as the old saying goes ?Slow work yields fine product?, the production output of Reference One per month was limited to 8 to 10 sets. Because different sound effect depended on different deployment of elements, Audio Space particularly provided 4 different sound effects for customers' selection. They were respectively thick sound, thick sound with high differential ability, slip sound and driving sound. This kind of unparalleled tailor-made manufacturing method effectively accommodates the requirements of customers, and therefore was satisfactory.

11 characteristic and meticulosity

In general, Reference One has the following 11 characteristics:

1. Split style: Class A Push-Pull Mono Block Power amplifier
2. RCA and Balanced input: Real balanced input.
3. 0, 4, 8, 16 ohm output: Convenient for matching loudspeakers with different impedance.
4. 845 driven by 300B: With EAT 300B matching Dawn 845 and Tube King matching Tube Queen, the timbre is bright and brilliant. Moreover, it can meet customers' requirement for customized 845 and 211 versions.
5. Audio Space Magic Power Cap: It is made of compound film imported from Germany, and is durable for 50 years' use. It has positive effect on timbre, dynamic features and hierarchy.
6. Using M-Cap Silver Oil as AC capacitor: Penetrative timbre, clear hierarchy and high differential ability.
7. Output transformer: In addition to circuitry design, the importance of output transformer should not be neglected. It is very difficult for DIY to reach expected effect, which is to some extent due to the restriction of output transformer. The frequency response of this Audio Space's masterpiece at 50W output setting is up to 10Hz to 40Hz (-0.5dB) with only 1% distortion. Whereas, at 75W setting, its frequency response is up to average value of 20Hz. It has excellent insulation, and can maintain its normal operation even after 12 hours 1600V power test.
8. Design conception
(a) Circuitry flow can pass from input to output end via power source.
(b) Elaborately designed arrangement of elements can effectively prevent the cross influence between magnetic force and heat.
(c) Rectifier and resistor subjected to cooling treatment can effectively accommodate the high temperature environment. Improper treatment may dry the capacitor and cause the explosion of tube.
9. Panel: Convenient for adjustment of unbalanced voltage, and can be used as indicator for frequency voltage.
10. Damping leg: Original damping leg and linear which can guarantee excellent damping effect.
11. Whole triode amplifying
Grade 1: 6SL7 double triode differential and amplifying
Grade 2: 6SN7 double triode push amplifying
Grade 3: 300B Buffer amplifying
Grade 4: 845 power amplifying

The manufacturing workmanship can be described as the peak of perfection, and its sound is also perfect. After long time maintenance at Lincoln's home, I spent the whole afternoon in testing. In other words, I was enjoying the perfect sound produced by Reference One. What we listened were all the well-known software. It was uncommon that Reference One could provide with us a thoroughly new feeling.
High performance of Tube King and Tube Queen

At first, I listened the "Autumn Tale" by Wong Hung Ying. All the sound of singing, piano and flute was very tender and soft. The advantage of 300B 845 were bought into full display. Tough you could not say it was real sound, it was really pleasing to ears. After that, I continued to listen "A Groovy Kind of Love" and "Getting to Know You" in the new album of Jheena, another Hong Kong singer. I also found the sound was very attractive which made you forget to change CD. Besides this, the clear detail displayed by Reference One was another reason.

Jheena's spelling was very clear, as if he was pronouncing English words. Reference Ⅰ thoroughly displayed this characteristic to the audience. Its unvarnished sound was appropriate. Naturally this kind of sound was produced by 300B, however, it was different from the sound produced by ordinary 300B. Although the sounds produced by 300B which I heard before was smooth and tender, they were too sweet and tender. Though they were able to cater to the taste of most audience who loved sweet music, they were not comprehensive to most of audiophiles who had variant taste. It was expected for Reference to bring into full display of Wong Hung Ying and Jheena's singing, which showed its strength for the first time. However, it would be too early to say that its performance was comprehensive based only on the two CD. After that we took a sharp change. We used it to play two breaking and rocking CD respectively by Duo Shouzai and Bamba. Immediately, Reference One showed its high speed. It brought into display the springiness of drumbeat and tightness of drum skin in an exciting way. The excitement created by it was so strong and penetrative which was different from that of produced by advanced transistor amplifiers. Its high differential ability made the sound scale more extensive and deep. In this sense, its performance far exceeded the ordinary 300B. Its ?breaking power? was an incredible surprise to every one following Cary CAD 805.
Super bass sound and high performance

Although Reference One is not as powerful as transistor amplifiers, its super bass sound is almost the same as that of them. Dorian's ?Whole Selection of Pipe Organ? is a challenge to all of amplifiers. Even the sound effect produced by ordinary amplifiers can be said as shaking. If you have ever experienced the super bass sound, you would inevitably be gape-mouthed. Jazz Variants contains some super bass sound which cannot be displayed by every amplifier. Even if they can be displayed, the sound would be not that good. However, Reference is able to achieve that effect.

Nightmare of A Double Bassist in Encore is also a melody we prefer for test. Its dynamic force of bass string sound can easily exhaust the back amplifier or the loudspeaker. The alt at high instrument position looks easy to handle, however, it is not an easy thing for power amplifier to clearly differentiate the Cello from the Bass if its differential ability is limited. Reference One thoroughly brought into display the extent of scraping between main strings and bow hair. One can feel the slight distinct between the tightness of timbre and slenderness of the cello at high instrument position.
Atmospheric Sound Effect and Flowing Noble Nature

According to our judgments, the most outstanding advantage of Reference One lies in its atmospheric effect. This atmospheric sound effect makes the sounds of other instruments more stereo and vivid.

The performance of CD mentioned above benefited absolutely from this kind of excellent atmospheric sound effect. While in playing "Berlin Gata", it thoroughly displayed the magnificent scale and natural hall sound, which thoroughly revealed the true qualities of Berlin Orchestra under the conduction of Abadu. It must be mentioned that though it was an old CD, the singing of this world-class singer as well as Shaham's violin and Pletnev's piano performance could bear repeated listening. The equipment used for this test were extraordinary excellent, which included the Gold Voice DP 100 CD dial, DC 101 decoder, Metronome Kalista dial plus C2A decoder, Mark No.32 front amplifier and Venture Diamond alt loudspeaker. It was natural that you might say that these equipment will surely create excellent sound effect. However, only half you said was true. Every improper operation in the process of deployment could cause the unqualified sound effect. Being at the last pass to the loudspeaker, Reference One of course held the balance. At the same time, as the support to well-known equipment, Reference One thoroughly displayed its dominant performance as well as free and easy style that enabled it to take a place among the Hi End equipment of world class.

In conclusion, among the local Hi-fi products, Reference One is the only equipment which teems with noble nature. It is not a short-term products imitated on the other products. It's a masterpiece produced on the basis of many years' experience and fine designs. I put special emphasis on the word "special", on the fact that in the near future, some cheap products with the same figuration and material will inevitably enter into market. I can tell you without any exaggeration that these products are only similar in figuration but quality. We sincerely hope that audiophile abandon the prejudice that local products are not powerful enough, and spare time to listen to this product which is regarded as pride of us.

Specification of Reference One
Output power: 75W per track (dynatron, class A, push-pull)
Output resistance: 0, 4, 8, 16 ohm
Input mode: Balance and Non-balance
Electron tube (per track): 1×6N9P (6SL7 or ECC35) / 1×6N8P (6SN7 or ECC32) / 2×300B, 2×845
Cube: 660mm×495mm×285mm (D×W×H)
Weight (per track): 55kg (net weight), 71kg (gross weight)
Some suggestions by Lincoln

On a summer day seven or eight years before, in Audio Space's Hi-fi shop at Apliu Street, I auditioned a 300B tube amplifier designed by him. Based on its excellent sound effect, reasonable price and high level of manufacturing workmanship, I jokingly said to him: "whether it is possible for me to make some modifications to the circuitry of this 300B and reduce to the maximum extent the material for shell, manufactures and parts?" After a while of thinking, Audio Space Lau replied with smile: "I have already had a similar plan in my mind, and I will bring into being the advanced 300B in due course". In the following several years, products with excellent performance were put to the market in succession. Just as before, these products won much praise, and its manufacturing level and sound effect were continuously being improved. However, we could not find the trace of advanced 300B. Every time I consulted Audio Space Liu, he always replied with smile: "I am busy in the manufacture of other new amplifiers, and the design for advanced 300B is still under way".

It was until last year, several weeks before the commencement of "Hong Kong Advanced Audio Visual Exhibition" did Audio Space Lau reveal to me with excitement that the design work for advanced 300B which lasted for many years was only a stage away from being put in market. The model of this product was Reference One, which would be formally produced after completion of debugging work. The first lot of samples should have found their way into the "Exhibition". As a matter of fact, to manufacture an advanced amplifier of flagship grade was more difficult than manufacturing any current model of Audio Space's amplifiers. As a result of it, even if Audio Space Lau tried his best, the Reference One has failed to stroke a pose in the exhibition. Moreover, there were still many defects with the manufacture of amplifier body. Its 55kg weight and two 300B used for driving 845 mono block power amplifier has already caused repercussions among the audiophiles. Everybody was auguring: "Inevitably, cost for this two single track back amplifiers is very high, and what about its sound and price? Does Audio Space have the ability to produce this kind of advanced equipment?"

As a matter of fact, it is natural for audiophiles have such comments on this 300B amplifier of flagship grade. However, the last question may be a bit too devaluation on Audio Space's design experience and high manufacturing capacity as well as local products. I have once found on the net that some friends made comments with evil intentions even tough they had never heard of this product before. I really don't know whether to laugh or cry.

Whether the sound effect of Reference One which costs 138,000 Hong Kong dollars is good or not? Whether it is worthy this price? I believe that readers who have already read Beetle and Simon's comment will surely have a preliminary impression. I can assure to you what they wrote are their real feelings which are the same with mine. Therefore I suggest readers to take time to experience the performance of Reference One, whether you want to buy it or not. Only after you experienced, will you get to know the design and manufacturing workmanship of Hong Kong people has reached the advanced level of Hi-End in real means.

On the basis of the matter on whether it is worthy of more than one hundred thousand Hong Kong dollars, I want to tell you what I saw. During the CES exhibition of this year, I once saw an old man immediately signed a check to buy this tube amplifier after 45 minutes' test in Audio Space Lau's room (He was conducting informal sound demonstration at Alexis Park at that time). It seemed that he has voted in favor.
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