- #4352 [香蚊人], 24-09-11 09:08
- #4351 [niceday009], 24-09-09 12:24Audionote Peter Qvortrup 多年前解釋点解制作昂貴之C Core 牛比EI 音質性能更好,好詳細
Posted by Peter Qvortrup (M) on August 22, 2003 at 06:04:47
In Reply to: Do you know why Audio Note classify C-core a higher class of OPT ? posted by Iceman on August 16, 2003 at 07:58:22:
Dear Iceman,
Any notion that any of you may have having just read the posts on this thread that an I-E cored output transformer (or even a mains transformer) is better than a similarly well executed C-core version using the same iron, should read this,
So Why Are C-Cores Better? Here is why,
Basic (very) domain theory tells us that magnetic steels function by two main processes, domain growth and domain rotation.
Under a low magnetising, field domains, which are oriented in the direction of the applied field, grow at the expense of their non-oriented and anti-parallel neighbours, this low field domain growth is generally reversible if the field is removed.
Under a medium applied field again domain growth is the predominant factor. However there will be some non-reversible growth of the domains, and a reverse field is required to return them to their original state.
Under a large magnetising field those domains, which were not oriented in the direction of the applied field start to rotate towards that direction. Eventually all of the domains are pointing in the direction of the applied field and saturation is reached.
This neatly explains the familiar shape of the B-H curve and hysteresis loop.
Essentially iron crystalises in a body cubic form and the domains are oriented parallel to the edges of the crystal, therefore an iron crystal will be easier to magnetise if the applied field is parallel to an edge, and will be most difficult to magnetise in a diagonal direction across the cube.
In a non-oriented material the crystals and the domains are oriented randomly, therefore it will magnetise much the same in any direction. However no direction is aligned with the preferred direction of all of the crystals, and a lot of the crystals will be oriented in the worst direction.
Therefore permeability is low and losses are high. The hysteresis loop will be wide and rounded. In a singly oriented steel (M4 etc, there are cubic oriented types which we use as well) the crystals are oriented so that two of the faces are perpendicular to the strip rolling direction, two of the edges are parallel to it and the other edges are at 45 degrees to the strip surface. In other words the plane of the strip cuts the diagonal of the faces, which are perpendicular to it. This means that the material is very easy to magnetise by a field parallel to the strip rolling direction as the domains are facing in that direction.
This makes for a material with a high permeability, low losses and a narrow rectangular hysteresis loop when the field is in the strip direction. But it also means that a field in any other direction in the plane of the strip will be trying to magnetise the crystal in it’s worst possible mode. The highest losses always occur at approximately 45 degrees to the rolling direction, in the plane of the strip.
The I-E Core.
Now, laminations are punched out of a steel strip such that the “arms†of the E point in the strip direction, however the back of the E is perpendicular to the rolling direction. The I is punched so that it’s longest side is parallel to the rolling direction. This of course means that with an I-E laminated transformer the flux has to curve round, across the grain at the corners, both at the junction of E and I and at the back of the E, and travel perpendicular to it across the back of the E.
In addition I-E laminations generally have whopping great holes punched just where you don’t want them. This means that a stack of grain oriented laminations ends up with better properties than a non-oriented stack but not by much. Quite serious curvature of the B-H curve starts to appear at around 1.2T to 1.3 T (Tesla) even though true saturation doesn’t occur until about 1.6T to 1.8T.
The C-Core.
Enter the C-Core, as the C-Core is wound out of the strip the flux always traverses the preferred direction. This means that a C-Core remains linear almost to saturation and then hits a brick wall around 1.8T maybe a bit more. The losses are much lower as well, and that translates into lower distortion as the hysteresis loop is narrow and straight sided. Let’s say that 1.3T peak is as far as one would like to go on lams, and 1.7T peak for a C-Core that is a ratio of 1:1.3. So for a given number of turns on a core of equal dimension the C-Core could sustain a 30% higher voltage across that winding.
That is an increase in power of 70% for a given level of core distortion.
Or translated into the realm of mains power transformers it explains why strip wound cores, especially toroidal transformers are so small for their power rating. Of course increasing the cross sectional area of a stack of lams can equalise the power rating but that brings about an increase in winding length and hence an increase in leakage inductance and capacitance.
Our special high quality output transformers use 50% nickel iron alloys, both oriented and non-oriented through customised proprietary heat treatment processes depending upon the application. These materials offer greatly reduced distortion at low signal levels, due to the very narrow hysteresis loop of these materials. The downside is their expense and lower saturation flux density, which in single-ended low power amplifier applications is not an issue.
From a purely practical standpoint, thin materials in the 0.1mm range are impossible to handle as large laminations, especially in the very mechanically soft nickel irons, and the C-Core format not only allows their use, but offers improved magnetic properties. Very thin laminations or strips are more important to very high permeability materials because eddy currents in thicker material, greatly reduces the effective permeability.
But remember that flux density is inversely proportional to frequency so at 1kHz the flux density in an output transformer will only be 2% of that at 20Hz, and 0.1% of it at 20kHz. Assuming 1.3T peak at 20Hz (for lams of M6) that gives 26mT peak at 1kHz and 1.3mT peak at 20kHz.
A high frequency power transformer such as used in a switch mode supply transformer would run the core at maybe 0.5T or more peak at 20kHz and then losses would become very significant. This is where ferrites with their very high intrinsic resistance become important.
Cobalt irons offer high saturation flux densities but they have a very wide hysteresis loop, not far from a semi-hard material and they don’t lend themselves to audio output transformer work where low level resolution is paramount, they should therefore be avoided.
This fact does not relegate cobalt based materials from other audio applications, for example permendur (49% cobalt) has uses in pole pieces for magnets in phono cartridges, loudspeakers and for electromagnets as the high saturation flux density allows for a greater density in the gap.
Here the material is generally driven into saturation by a DC polarising field.
Conclusion.
Given correct calculation, interleaving, dimensions, wire quality, etc. a C-core output transformer will ALWAYS outperform an equivalent I-E core, by a factor of at least 1.5 to 1.
Hope this answers your question, sorry it took a little while to formulate a reply.
Sincerely,
Andy Grove &
Peter Qvortrup - #4350 [niceday009], 24-09-07 14:25#4349
睇返我部20年前作品,諗返起當年对直熱三極管單端機之熱誠,其實我一直冇減
最後修改時間: 2024-09-07 14:26:45 -
- #4349 [WilliamsonAudio], 24-09-07 07:45#4335
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果個係見到Kondo Kegon而有感而發造的,是我廿幾年前嘅DIY, 用我地今天已知的經驗,果個机壳D輸入訊號線成米長,唔係Audiophile 之設計
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今早終於找到幅相。是好靚。值得分享。 - #4348 [WilliamsonAudio], 24-09-05 23:59#4335
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呢樣重要事後期各大廠亦仿效,Ayre Charles Hensen 又係signal purity 之先驅,佢部KXR 入→放大→出,全程不超過4吋路程,係Shortest Path冠軍""""""""
4 吋應該已經是極限。
我自己前級嘅記錄係14cm(約5.5吋)。 WBT RCA 直焊ELMA Volume. 0mm 信號線。
https://m.review33.com/forum_msg.php?db=1&tstart=0&s=&topic=93191117231638&start=300&sort=&number=359 - #4347 [WilliamsonAudio], 24-09-05 23:38#4345
綠色PCB 是燈絲穩壓. - #4346 [WilliamsonAudio], 24-09-05 23:36是好奇怪,M3是用屏蔽線。
可能原因就是商業決定。更高級的M8“”升級“”用不屏蔽的純銀線。是買點上的升級,視覺上又有升級(大大條銀線)。
因為就係見到他不用屏蔽線。但又紮在一起。所以就用儀器check 下。結果是沒有違反物現象。是有cross talk. - #4345 [niceday009], 24-09-05 23:20Wilson, 我都覺得奇怪,UK audionote 係佢部Jinro D線較短但前级超長,UK audionote 應該都好有經驗,点解佢唔放佢D出名屏蔽信號線入部机内,而就咁twisted 正負兩條wire就算?佢而家crosstalk應該好大
你相中那兩塊綠色板仔係乜?
最後修改時間: 2024-09-05 23:35:46 - #4344 [WilliamsonAudio], 24-09-05 22:56#4335
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記得你曾過料話輸入訊號線一吋都嫌多,長signal wire影响sound quality ,確係事實,依家我部Ultimate 845輸入RCA到Volume制只有兩吋路程,合符其中靚声要求,胆机輸入線要盡量短係Kondo San係Ongaku首次implemented, 係佢之前揾唔到任何机比佢短,後來Peter Qutrop 學到其好處做返一樣短,Peter係Audio Innovation 時輸入線一樣係好長,佢加入Audionote 才做返短
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Audio Note 前級的線還是比較長。信號由後面RCA走到去前面面板Volume。由輸入到輸出。整體的線還是好長。當然每間公司的設計理念不一樣。圖片是M8.太約有80 cm , 而且喜歡左右訊號線紮在一起. 左右信號會互相干擾,我自己出測量過好多次。channel separation 指標性方面不是太突出。這個指標是同音場的闊度有關係。
最後修改時間: 2024-09-05 23:05:35 - #4343 [niceday009], 24-09-05 18:44另外而家好多以前係度班高手最近係一個WhatsApp 羣discuss 技術,我都有参加,整整下呢度單端同好會变到冇哂班高手蹤影
呼籲各高手如果係熱愛直熱三極胆之高手回來繼續潻加經驗及内容,畢竟R33係一個公眾地点可以永遠把宝貴内容保留(希望R33 admin睇到),令R33單端同好會变成一個知識宝庫 - #4342 [niceday009], 24-09-05 18:05刚時到蚊兄你個post, 又收到一位師兄詢問
可能你等了好耐,見到你玩新玩具之喜悦調轉係我自己都會咁
刚收到一位師兄詢問,澄清一下
不過我心目中部Final Ultimate 845仍未完成 ,現在confirmed 設計只有IT, OPT牛是通過,外觀結構及最終綫路仍然在實驗中,未完全通過自己標準係未考慮做量產,因為決定量產投入之effort & investment 就唔同DIY 三兩部
呢度有些朋友認識我二三十年,有幾位朋友希望我做快D,我表示:
我其實係現在坐在电輪椅及只有一隻左手嘅傷殘人仕,腦血管爆後我離開做了三十年嘅大集團公司,係無所事事情況下把時間寄托於我人生興趣之音响,但我係去享受人生果隻,所以我唔會迫自己做快,好似以前做世界性地鐵project咁趕,蚊兄等咁耐希望你認為值得
你部845係我做試製樣版机時搭單一起做的,老友对D声表現滿意我都非常高興 - #4341 [香蚊人], 24-09-05 15:22可能之前講得唔清楚
各位這部845 ultimate 當時係我托niceday009幫手整部無負回輸845膽機,而咁啱佢又係設計緊部高檔845,所以先有機會可以有這部845 ultimate。只不過我之後會送去niceday兄執個表頭同埋檢測部机setting,咁啱佢大厦又換电梯,所以先送去我屋企先。 - #4340 [香蚊人], 24-09-05 13:06各位師兄,請唔好PM問我價錢,因為這部機係niceday兄嘔心瀝血既大作,我只係好彩得到niceday兄不計較下,將部”初”機讓俾小弟試聽。詳情大家可以PM niceday009兄。
大家想試聽就當然無問題,等部845ultimate再煲一段時間大家可以上小弟家中試聽,之後等niceday兄個場部電梯整好後,部機會放係niceday009兄個場,到時大家可以約
niceday兄聽下845推JBL 1400的效果如何。
最後修改時間: 2024-09-05 13:09:16 - #4339 [香蚊人], 24-09-05 11:53麗磁隻牛,原來咁普通。niceday兄你做牛一絲不苟,小弟佩服。今次部Ultimate 845真係令小弟大開”耳”界!
聽緊可能要十幾二十萬先聽到既聲音。
最後修改時間: 2024-09-05 11:56:18 - #4338 [niceday009], 24-09-05 11:26蚊兄你用Ultimate 845机力度明顯更大係因為用全段(即所有放大級)為無負回輸綫路
而Ultimate 845設計可以出到A1 27W, A2 41W, 比丽磁最高輸出只有23W, (其中17W 係A1, 23W 係A2), Ultimate 845其甲類輸出功率差不多係丽磁219嘅兩倍
另外最大分別係你对Double C Core Hi B (Nickel Impregnated )輸出牛有成8kG 一隻有. 75亨,比起只有4.5kG重 35亨之丽磁牛有明顯更大之Dynamic Power Transfer 能力,單端机牛之功率余度係声音動態表現好重要,Audionote 經常强調,我試過都係咁,聽音樂全程有動感係好重要
丽磁219部机重成55kG但佢用之輸出牛才4.5kg一隻
最後修改時間: 2024-09-05 11:41:26 - #4337 [香蚊人], 24-09-05 09:57另外真係要讚一讚niceday兄經佢手攪所有牛,質素同用料真係頂級。niceday兄對牛既用料同知識真係好豐富。經佢測試過既牛我都好有信心,因為真係有數據支持,唔係估估下。
最後修改時間: 2024-09-05 09:57:54 - #4336 [香蚊人], 24-09-05 09:42部新845初聽聲底同niceday兄部”改219”好似。
不過力度係我對JBL 4349度就好似更強。
另外無負回輸單端機應該既速度同人聲既空氣感都交足晒貨。
暫時用cheap膽都有固咁既效果,如果換返靚膽提升可能會仲大。 - #4335 [niceday009], 24-09-05 00:29Wilson,
果個係見到Kondo Kegon而有感而發造的,是我廿幾年前嘅DIY, 用我地今天已知的經驗,果個机壳D輸入訊號線成米長,唔係Audiophile 之設計
記得你曾過料話輸入訊號線一吋都嫌多,長signal wire影响sound quality ,確係事實,依家我部Ultimate 845輸入RCA到Volume制只有兩吋路程,合符其中靚声要求,胆机輸入線要盡量短係Kondo San係Ongaku首次implemented, 係佢之前揾唔到任何机比佢短,後來Peter Qutrop 學到其好處做返一樣短,Peter係Audio Innovation 時輸入線一樣係好長,佢加入Audionote 才做返短
呢樣重要事後期各大廠亦仿效,Ayre Charles Hensen 又係signal purity 之先驅,佢部KXR 入→放大→出,全程不超過4吋路程,係Shortest Path冠軍
最後修改時間: 2024-09-05 00:45:42 - #4334 [WilliamsonAudio], 24-09-05 00:00Eric,
你還有一個並聯300B 的機殼。設計得好好。
相片我找不到了。 - #4333 [niceday009], 24-09-04 23:20>>不過我好鍾意Premier Audio嗰啲機殼嘅外觀,真係好靚仔
去設計部DIY 机机壳美觀亦是自己興趣之一,我相信任何做DIY設計部胆机那些人,都想自己部傑作靚仔
自己都係發燒友才會花大量時間去實驗,現在做緊大量實驗做款新DIY机,新綫路,新变压器材料,新款壳用透明玻璃加鋁側板做牛罩,遇到各種Challenge, 但仍堅持此外型更靚,希望快D搞掂 - 下一頁 (5 of 222)
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(我自己要求,因為我聽CD同黑膠input得一個對我無問題)
我同niceday 兄星期二晚再聽部機都俾部機40W推力所嚇到,部機現在動態驚人,聽2022 hifi show sacd,放第14首”打鼓山傳奇”係我個場將我對4349推到地動山搖,勁驚樓上樓下會報警投訴。
最後修改時間: 2024-09-11 09:09:42