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JMF Audio PCD102 and Pranawire Linebacker GP to complete 淨電內循環

edited January 2023

The use of technology in performing arts has to be relevant to the content itself.  If it is irrelevant, then technology becomes a gimmick.  Audiences understand live performances offer tangibility and corporeality that no digital technologies could ever replicate the “presence”.  Resources are often spent on visualisation technologies because they are easy to justify.  To compare, the quality of sound is often neglected due to inadequate education on this front for too long.  Audiences never know the quality of sound can be improved tremendously if noises from electricity powering audio electronics are removed. The end result is much relaxation to our ears even at loud volume. The flow of music becomes much more coherent touching our souls.  It is such a mind boggling memorable experience.  Anyone would consciously return to the same venue for music enjoyment.  To my knowledge, such technology has never been deployed in public performing venue.  

Audio Exotics (AE) was given a precious opportunity to do a demonstration of JMF Audio PCD102 35th Anniversary Edition AC filter (from France) at the Hong Kong Academy for Performing Arts (APA) on March 9.  Our goal is to illuminate the utmost importance of providing clean power supply to the service of music either in a live concert, recording studio or any room for playing music involving electronic amplifications.  This professional instrument from France improves the clarity of sound in the areas of harmonic decay elongations, dynamic contrast, tonal colours, localisation of images, mid bass attack, focus, clarity of diction, and radiation of energy in a controlled manner etc.  

We were honoured to have the presence of Professor Stephen Chow (Council Chairman 校董會主席 of APA), Professor Gillian A. Choa (Director 校長 of APA), Professor Martin Lau (Dean 院長 of School of Chinese Opera), Wa Yuen (Associate Dean 副院長 and Head of Media Design and Technology), Albert Ho (Lecturer in Music Recording) and Sanco Lee (Technical Sound Manager) attending the demonstrations.   On the AE side, Chris Leung (CEO and Founder) and JLam (Managing Director) were present. 

We quickly set up the JMF Audio PCD102 in one of the music rooms on the 7/F.  We then listened to the first track of the famous recording - Cantate Domino - recorded inside a church in Sweden for a start “without” the electronics connected to the JMF.  I made a short introduction of the French instrument. Then we connected everything to it.  Professor Stephen Chow and Professor Gillian sat in the middle and listened again.  Within a minute, Professor Chow said to me, “It is much more transparent.  I can now comprehend the recording was inside a church.  Before the connection with JMF, I couldn’t tell.  The energy of the organ is much more solid with better focus too.”

Other professors were astonished to ear-witness the tremendous improvement of sound quality immediately.  Professor Gillian commented the sound has much more purity on top of clarity.  Sanco Lee told me he could tell immediately from the very first note with much more harmonic contents.  The atmosphere of the room was clearly elated by the music due to betterment of sound quality through cleansing incoming electricity.  Technology in this context represents the means.  The end result is joy.  

JLam, MD of AE (Left) and Professor Gillian A. Choa (Right).

Professor Stephen Chow was eager to experience the impact of such on Chinese Opera playback especially on his own voice.  He is the protégé of Lam Kar Sing (林家聲), the seminal grand master in Chinese Opera.  Once again, within two minutes, he was convinced by the significant improvement in the clarity of his voice.  The high frequency harshness was gone.  His performance is indeed lyrical.  Chinese music instruments are mostly percussion type without too much harmonic decays compare to western music instruments such as violin and cello.  As a result, it is less pleasing to the ears particularly when AC (electricity) noises are also being amplified at the same time.  Indeed, the calmness aspect of Chinese opera during playback was restored completely when JMF was connected.  All of them could then comprehend the “silence between notes”.

Next, we brought the JMF PCD102 to one of the control rooms for testing with active speakers playing the same music tested beforehand.  The positive impact on sound improvement was consistent.  Professor Gillian commented the vocal became more 3D, more palpable and voluminous with the JMF.  Without it, the image of the vocal was flat.  

We are thankful of the subsequent APA tour arranged showcasing the facilities alongside the technical operations behind the theatres.  In conclusion, it was such a delightful session learning from the intellectuals in performing arts.   

Control Room of the main Theatre 


It is God’s will prioritises our hearing/listening senses over others.  According to ground breaking researches done by linguist Age Viberg in the early 1980s from the Netherlands, hearing ranks second place after vision, followed by senses of touch, taste and smell.  Likewise, hearing is the last sense to disappear in human life according to numerous medical researches, as God wants us to listen attentively until the last minute.  Technology possesses an extraordinary capacity to shape our understanding of performing arts and music.  Intelligent application of it enhances our listening senses to the betterment of humanity.

Professor Stephen Chow, JP, GBS (Golden Bauhinia Star 金紫荊星章) on the right. Chris Leung, CEO and Founder of Audio Exotics on the left. 



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    I am awaiting for the delivery of the 2nd one. 
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    edited September 2022

    Hi all,

    In the HK Audio Show 2022, I observed that several JMF PCD102 were installed in the showroom of Audio Exotics. After discussions with Marvel, who suggested me to prioritise building a core supporting architecture for my system to mitigate noises, I decided to order one. It was delivered to my home a few days ago.

    After housing it in the rack, I let it warm up for a while. I must say this a/c power conditioner/filter is much more than an audio accessory because its effects are tremendously more than my expectation. It should be classify as an instrument.

    I used to/am currently using some other brands of a/c power conditioner, isolation transformer and power regenerator.  Most of them are able to cut down a/c line noises by blocking d/c voltages contamination thereby resulting in a more black background.

    However, the negatives for some are:

    1.      alters tonal balance of connected components;

    2.      limits dynamic range;

    3.      some audio frequencies and several details of the songs are perceived to be cut

    4.      results in a flat sound stage without adequate presence feeling  

    However, the effects of JMF PCD102 from my initial listening seems to be

    1.      a blacker background with much less noise;

    2.      no loss of music details

    3.      more holographic real-life image;

    4.      adds horse power to connected electronics; I can use a smaller volume setting.

    5.      no perceived dynamic compression, the lower and higher frequencies extension are tighter with pristine clarity 

    The effect from PCD102 provides me a much better listening environment to unleash the true potentials of my audio system.  Building up a core supporting structure is very important for all your gear to show its best, highly recommended!

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    edited March 2023
    淨化後的電源供應給音響器材主要改善「背景明淨度」,但不會大幅改進能量擴散度。原來要再下一城,必須阻止各器材的剩餘噪音回輸至系統內(尤其是數碼訊源、大電流功放,以及超低音內的D類功放),因為這種污染嚴重壓抑了中低/低音的能量吞吐。根據我管理四個不同系統的實地測試(所有系統均有Tripoint Audio Troy Signature NG/Elite NG處理地噪),我的結論是用JMF Audio PCD102/302電源處理器負責第一階段的工作 — 過濾在交流電𥚃的超高頻噪音,而Pranawire研發的Linebacker GP (silver power cable)就負責第二階段的工作 — 阻止剩餘噪音回輸到系統𥚃。我形容此系統為「淨電內循環」。

    在應用Linebacker GP silver前,Cessaro項羽(有源超低音)的音量是+1.5db (音量最大限是+12db)。GP工作200小時的過程期間,不停聽測了不同種類的音樂後,我需要將項羽的volume 減至 -4.0db,即從原本位置下降了366%,才能將系統能量分佈回服平衡,因為現時-4.0db的能量發放,已經大大超越之前+1.5db的音量,(為了簡化解釋,我沒有列出input sensitivity的數字。)
    整個低音部份的驅動力大幅增加,其穿透性、穩定性、尤其是中低音的衝擊能力。龬琴家左手發力彈奏時attack的力度,是我從未感受過的紮實,低音鍵的諙波帶力度經琴腳 (琴鍵左邊的bass leg) 散開,整個龬琴的存在感非常之穩重,因為連其物理特性也表露無遣。另一具體例子是任劍輝的敝氣音所引發的中低音能量擴散,震撼心弦,令我真正明白何謂技驚四座。一直以來,加了超低音後,原來我主要是聽多了低頻在60hz以下伸延(frequency extension)所帶出的能量。這並不代表低音能量的推動力已經到位。

    其一是因為房間載不了多餘的能量。聲樂効應問題沒有解決,通常是因為地方面積不足、對room acoustics認知不深,求助無門等;就算想解決,家人又可能不允許廳內放多餘的聲効工具。環境的限制,令能量不能過分發放,選擇聆聽的音樂自然偏向了一把人聲、兩三件樂器、慢板爵士樂等,重播得laid back才能聽得舒服。在能量不足的困局下,難怪用了電處後,有朋友認為動態被壓縮(噪音又係一種能量),所以選擇把器材直接插入牆𥚃的電蘇。我曾幾何時也有此見解,但高頻噪音在交流電𥚃自由𣈱泳,又令耳朵很快疲倦。

    另外一個大問題就是缺乏對 “增益” 管理的認知,準確拿捏機與機之間的增益配合乃是重中之重。以下是一個實例,一部瑞士品牌的DAC以5V輸出至另一瑞士品牌的前級,令到前級的輸入級超載(不懂去調低DAC的output/前級的input level),導致中頻嚴重壓縮之下,令中音能量突了出來,蓋過了高音細節,毀掉了中低速度。在此嚴重壓縮能量的背景下用電處,結果係冤枉了它。
    今文帶出「兩階段淨化電源噪音」的概念:先供應淨化了的電給各器材,然後再攔截剩餘噪音回輸至系統𥚃,為之一個 “淨電內循環”*。

    是否每一件器材也需要用一個Linebacker GP,我認為不必,因為第二個的効果通常比第一個少(Law of Diminishing Return)。應用在什麼位置,也需要考究。那件器材回輸最多噪音就用在那裏,因為被攔截了的噪音,不能染污整個系統。
    Chris Leung
    * 我定義系統的”外循環”為功放/喇叭與房間的關係。
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    edited January 2023
    Happy new year to all! 大家好少在這𥚃交談。老人始終喜歡舊式溝通。內循環概念是新的想法,我最為同意文中提及大多燒友喜歡直插功放入牆電增強動態的情況,可惜我認識台灣燒友把功放直插牆,無人可以重播到郭富城的狂野之城的味道,只是背景大聲直沖,人聲粗,節奏生硬。我明白原來玩得到不到位,用iPhone錄後比試,即見真章。
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    Happy new year! Chris,你應該要出一本書了!你的寫作水平研究態度,經驗,人脈網絡,社會認同已經到達了一個區域,可以做更大的事。我想可以影響整個industry。Go for it!
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    Hello guys, happy new year! I am travelling in Europe.  I agree with Jeff that we discussed a lot less here but not because of we aren’t as passionate as before. It is the change of the society, of which, everything is moving too fast with pictures and billions of new information per seconds. I am glad Chris did not pursue this path. Instead, he had chosen to write in-depth articles from time to time. That is precious. You don’t need to be judged by how many likes obtained like the young people.  It is the weight and the people who understand you also respect you that matter.  
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    edited January 2023
    新年快樂!回看2022多篇Chris寫的文章,全部都係用心之作。我認為這𥚃不是吹水文化,而我好鍾意這種專業,沒跟風,我覺得學到很多新的想法。另外一個原因這𥚃少了交流,應該係大家跟不上他,但又喜歡見到AE不停突破,至今茫茫路音響劇係大突破,質素不容置疑,應該上更大的舞台。從前是消費後的快樂分享,容易好多,現在是技術知識分享,層次不同,樂見此路。Mr Dynamic應該是最明白Chris的一個,因為他清楚交代到心德,我喜歡數篇他寫的文章。其實Roman也寫得好。你們不是寫得很多,但係有心機,而且你哋係受到腦震之後而寫的,所以感覺直接。



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    edited January 2023
    Hey guys, it’s been awhile! Happy new year! I am getting older here on a retired mode in Hawaii.  I was not as active as before when I was in the greediest industry of all - investment banking.  As Chris started writing more in Chinese, I could not benefit from his advancement in knowledge. But what those in English, his writings on Arya Air Blade Signature, WELLFLOAT Babel, and Acoustic Grove System are instant classics.  There are so much detail to be digested, so much after thoughts. It is not exactly an academic article as descriptive emotions are also very well conveyed to reader. 

    My daughter is also an active follower of AE. Her opinion of Chris writing more in Chinese reflects changing balance of the world and there is an unspoken advantage of writing in native language - foreign forums have no ideas of what is he writing thereby less misunderstandings (a nice word, you guys know what she means).  I stop reading those since a few years. We all know internet is full of shit, and everyone is doing some sort of business here and there. But I hate those forums often launching attacks all over due to vested interest differentials, followed by heavyweight coming out to moderate here and there for fuck peace. Damn it, this place talk senses even if I don’t understand all. My daughter who studies Chinese history always translates for me. And she told me that the Chinese writings here are well researched with thoughts clearly articulated. She told me these aren’t poetic writings but a new type of editorial blending science, music, history and techniques to achieve higher musicality goals. 

    Does my daughter explain well? 

    Guys, keep up the good work! I know Hong Kong went through so much shits in the past few years. I am sure light is already in front.  

    Best Wishes
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    edited January 2023
    Sorry Voy, you are going to miss another Chinese piece by me.  
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    Marvel老弟,這篇分享文章寫得不錯。我想知道LXE 和 LGP的分別,你可否分享?
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    edited March 2023



    由於功放帶電流去揚聲器,所以喇叭線/揚聲器是直接受惠於「淨電內循環」的配置。喇叭是聆聽者與重播音樂之間的最終介面,而位於之前的喇叭線,盛載了帶著電流的音樂訊號,把守著系統發聲前的最後關口,所以我決定把用了四年的Esprit G8 Gaia 喇叭線,換了同型號的G9。

    一年前,《神曲工作室》內的Robert Koda 巨匠K160功放,我由一對Gaia G8喇叭線,升級到兩對Gaia G9去服侍Goebel大神曲揚聲器。進步 ”最主要” 原因,(G9比G8優越是次因),是改變了接駁配置由Single Wire為Bi Wire,分工合作之下,所帶來的鬆容感不可以同日而語。換句話說,二對G8 駁bi wire比一對G9好。


    我又必需強調線材的重要性,因為它們不是配件(沒有配件,系統也可以開聲;但沒有線,不能開機),而是肩負連結系統𥚃各級的責任,尤如人體內的血管。由於線較硬件容易更換,測試容易,改變聲音能力極大,因此粗略的AB比較,容易强化說服力。因此線材應用的經驗已被通識化,例如膽機用銀線、晶體機用銅線、大功率功放用大電流電源線、貴機一定配貴線等。我不否定這些經驗,因為狹義比較的結論必然強,但標準的形容詞通常只限於 “厚、薄、肥、乾、滑、勁、清、濃” 去描繪音色。


    1.由前級至後級的訊號線選擇,應該取決於訊源的增益,以及喇叭的靈敏度。假設數碼信源的output voltage超過4V,那麼它有可能令前級的輸入級超載(overload)產生壓縮,除非可以調較,否則用能量大的線材可令情況更差。相反,如果前級是無源類別,4V的output 又未必會衍生超載問題,可以選能量較大的線材。 

    2. 由升壓牛致唱放此環節可以不需要能量太大的線材,因為訊號已經被牛放大了;但由唱臂到牛這一段,假設是低輸出的日系唱頭,這段絕對需要屏蔽做得好兼能量豐足的線材。相反若然是高達1 mv的唱頭,一對普通有屏蔽的phono線已經足夠。

    3. 超低音內的D類功放的阻尼系數極高,不需要再用控制力強的電源線。反例,膽功放阻尼系數低,控制力比不上晶體管功放,雖然線材不能改變物理性,但可以應用控制力強的電源線,作為“輕度” 彌補,但不要有太大期望能扭轉乾坤。


    既然硬件配置是決定線材表現的主因,那麼家中系統成就了的“淨電內循環”(1 x JMF Audio 302、4 x Pranawire linebacker GP on Cessaro 項羽超低/Rivieralab AFM 100 SE),勢將Esprit Gaia G9啦叭線發揮到盡。人盡皆知的 “麥田之歌”在位於瑞典東南面的Osterhaninge教堂內錄音。教堂內的迴音較大,所以重播男聲時,通常有不集中和結象鬆散的感覺,我一直以為是正常,今天才知道其實係錯。

    通常教堂內由500hz到1,000hz的reverberation time大約是2.0-2.5秒(石牆反射令聲音停留在空氣中長久一點,制做景深),此乃是教堂常見的聲効特性,古代建築師設計目的,就是要增加擴散度的同時,也要肯定每人在教堂內頌聖時聽得清楚。我看到前排的合唱團  ”站立” 合唱詩歌,意指我感覺到他們身體的存在(之前只係感覺到由頭至頸部),聲音非常實淨,尤其是男音,聽多了多把男聲在場地後排(從前看不到是因為他們和噪音混合起來)。笛手的呼吸停頓位非常清楚,能夠容易分辨到泛音和堂音,我驟覺坐在教堂裏呼吸共同空氣。我主觀認為這是麥田之歌重播的絕對標準。

    蕭斯達高維契第5交響曲(蕭五)是極具傳奇性的作品,我剛經歷過的重播,令心情激盪,極度震撼!由強勁的定音鼓帶出鏗鏘銅管樂器的主旋律,及後小提琴奏出具節奏性的第二旋律,突然又加入了小號,配以絃樂如警報般的連弓和碎弓,瞬間衍生出的能量,將樂曲氣氛變得緊張。一輪亢𡚒之後,中段樂章突變得一片觸模得到的孤寂。然而豎琴的出現帶來曙光,木管樂器慢慢帶回主題旋律,絃樂及鋼琴的八分音符節奏,快速驅散陰暗氣氛,最後銅管樂和敲擊樂再度加入,將調性由小調變成大調,象徵着勝利,使心內有種肅然起敬的震撼。難怪當年的初演,在第四樂章後,觀眾站立拍掌長達半小時。這個測試已經肯定了Gaia G9喇叭線極緻的水平。

    可是當我把4 x Linebacker GP從功放和超低拆除後,麥田之歌內的合唱團站立感完全消失(頭至頸部仍然保留),男音鬆散,影深銳減。蕭五的緊湊感變為平淡,原因是低音能量下降,包圍感驟降,管樂的金屬感退色、管弦樂團強奏時亂了陣腳,心內再沒有拍手的感覺。那麼我能夠概括Gaia G9喇叭線不夠好嗎?

    如果我沒有設置 “淨電內循環”的架構,而純粹是作G8與G9的AB比較,那麼結論又會否一樣呢?答案是一定不同。線材的評論一向以來從不考慮累積性的因素,所以不對稱地強調其魔術性效果*。


    “不再痴線” 此文的主旨在於提供擇線前要考慮的因素,以及提醒累積性因素的重要性。不管是什麼品牌的線材,也逃不了受制於硬件的技術性設置;可是它非配件的性質,卻是無可置疑。


    *當然有例外的個案,例如Gaia G9 Ethernet cable/Dalby Meda QF Ethernet cable。

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