Translation ofTechnical Hobbies

City University of Hong KongCTL3352

Scientific and Technical TranslationIvan Yeung

What is Super Audio CD?What is Super Audio CD?SACD SACD 是甚麼？是甚麼？ It looks just like a normal CD, but that’s where the similarity en

ds. The SACD difference is breathtaking. The difference in sound quality is so great that you have to hear it to believe it! 它看來像一張普通的雷射唱片，但共通點就僅此而已。 SACD 的

差別教人屏息靜氣。音質差別之大，未曾親耳聽過，實在難以置信！

Thanks to revolutionary technology called Direct Stream Digital (DSD) encoding, SACD represents the highest quality sound source available today. 有賴革命性的直接串流數碼 (Direct Stream Digital, DSD) 編碼

技術， SACD 是今時今日頂班音質的音源 * 。 Thanks to an amazing 2,822,400 samples per second, you get au

dio performance that no other format can deliver. 有賴每秒 2,822,400 次採樣， SACD 可達至其他制式難望項背

的音響表現。

Not just a CD, but a better CDNot just a CD, but a better CD非同凡響的 非同凡響的 CDCD Time for fun!

For example, the frequency response delivered by DSD is almost five times greater than that delivered by normal CD. While CD frequency response extends to 20,000Hz, DSD technology can theoretically reach 100,000Hz.

舉例說， DSD 提供的頻率響應幾乎為傳統雷射唱片的五倍。 CD 的頻應可達 20,000 赫 / 週 * ，理論上， DSD 技術卻可達 100,000 赫。

And with a dynamic range of 120dB compared to 96dB on CD, Super Audio CD goes right to the limits of human hearing and beyond.

雷射唱片的動態範圍只有 96 分貝，而 SACD 的動態範圍則達到 120 分貝，超越能聽範圍，直抵人類聽覺極限。

VTV Octal Line Stage VTV Octal Line Stage ProjectProject真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 (( 設計設計 )) After a dozen years of listening to “pe

anut tube” preamps using 12AX7s or 6DJ8s, I asked Eric Barbour to design a simple, good sounding octal-based preamp.

聽了使用 12AX7 或 6DJ8 的「花生管」前置放大器多年，我請艾力巴布爾設計一個既簡單，音質又高的八腳管前置放大器。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 As many of you know, the reason there are

so many “peanut tube” preamps is because these tubes are small and cheap. 眾所周知，市面上有那麼多的「花生管」

前置放大器，是因為這些管子細小便宜。 眾所周知，市面上的「花生管」前置放大

器那麼多，是因為這些管子細小便宜。 Time for fun!

By the way, so is their sonic performance.

但所謂一分錢一分貨，音效方面就自不用說了。

順帶一提，它們的音效也不外如是。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 Miniature dual triode tubes typically have a s

mall soundstage, tinny sound, are subject to microphonics and can be irritating to listen to. 小型雙三極管一般音場狹小，聲音差勁，易有顫噪音，聽了足以讓人煩躁。

小型雙三極管一般音場狹小，聲音差勁，容易撿拾噪音，聽了會難受。

Short of using obsolete 56 or 76 triodes, we decided to use the venerable 6SN7, that can still be found for reasonable prices. 不想採用過時的 56 或 76三極管，我們決定選用現在還可用合理價錢買到，大名鼎鼎的 6SN7 。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 The 6SN7 typically has a larger soundstage an

d is super smooth. 6SN7 具有典型的廣闊音場，聲音極為流暢。

As with all tube types, different brands and batches can have noticeably different sonic signatures. 和其他所有型號的管子一樣，不同廠牌和不同批生產的，音響特質可以非常不同。

Time for Fun! The beauty of this line stage is that you can

experiment with the literally dozens of 6SN7s types to get exactly the sound you want.

這部前級的妙處，在於你可從數十款 / 多款 6SN7 中挑選合口味的類型，從而獲得理想的音效。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 The circuit design of this project is a cl

assic cathode follower driven by a gain stage. Two 6SN7s are used, one per channel. 本前級電路設計為由增益級驅動的經典陰極輸出級， 每聲道用一支 6SN7 ，全機共用兩支。

Overall gain of the line stage is about 12, which should be adequate for most applications. 高電平前級的整體增益約有 12 倍，

應可滿足大多數用途所需。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 It is possible to use this preamp with so

me solid-state power amps, but not all. 本前級可與一些晶體管後級放大器搭配

使用，但並不是所有晶體管放大器都行。 A 5Y3GT tube rectifier is used in this desi

gn, (Figure 1), because tube rectifiers add more “magic” and 3D to the music when compared to typical cheap silicon diodes. 本設計採用 5Y3GT 整流管 (圖一 ) ，

因為和廉價的硅二極管相比，真空管整流管讓音樂更立體，更有「魅力」。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 With this transformer, you could also u

se a 5V4G, but do not use a 5U4, because the filament current is too high. 用這個變壓器，你也可以用 5V4G 整

流，但別用 5U4 ，因為它需要的燈絲電流太高了。

DC heater power is derived using Schottky diodes. 燈絲直流電源由史卓基 (Schottky) 二極管提供。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 Time for fun!

In order to keep hum to a minimum, copious amount of filter capacitance were needed to keep hum below the 1 millivolt level.

為了把哼聲 / 雜音降到最低，使用大量濾波電容，把雜音控制在 1mV 水平之下。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 The power transformer is a Hammond

270BX (550V C.T., 5V@2A and 6.3V@2A) which allows for a 370V plate voltage on the 6SN7s. 電源變壓器型號為漢蒙 270BX (550V 中間抽頭 , 5V@2A, 6.3V@2A) ，可為 6SN7 供級 370V 屏壓。

Higher voltages make the tube more linear and more “exciting” sounding. 電壓愈高，管子線性愈佳，聲音愈生

動刺激。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 The power supply schematic, (Figure 1), al

so shows how to wire this amp for 12SN7s or 12SX7s if you desire. 如果想採用 12SN7 或 12SX7 ，圖一的

供電線路圖亦表示了接線方法。 Time for Fun!

Figure 2 shows one side of the line stage and indicates all component values.

圖二顯示了前級的一個聲道和全部零件的數值。

Note that the line stage has switching for three inputs.

注意前級有旋紐可選擇三個輸入。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 We used an old Dynaco PAS-3 selector

switch for this task, but you can use a higher quality gold or silver contact switch. 我們用了舊大力高 PAS-3 前級放大器

的選擇旋紐，你可以使用品質較高的金點或銀點接觸旋紐。

Coupling capacitors used are the Ultra-Tone Silver Foil in oil rated at 0.4µF@650V. 交連電容用了 0.4µF@650V 的超音油浸銀箔電容。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 Time for Fun!

These caps are clear, deep and huge sounding.

這些電容音像清晰、音場遼闊深廣、規模宏大壯觀。

The volume control is a Noble dual 100K type. 音量控制旋紐是貴族牌的雙 100K 類型。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 Performance was improved significant

ly when we installed a Gold Point dual 100K stepped attenuator. 當我們安裝了金點雙 100K 級進衰減

器時，聲音表現明顯提高了。 Adding the Gold Point cleaned up the s

ound and reduced any mistracking of the channels. 換上金點旋紐，聲音的清晰度提高，兩邊聲道的失衡降低。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 Time for Fun!

This preamp is a super smooth sounding unit and is very easy to listen to for extended periods without listener fatigue.

這部前級聲音極度順暢圓滑，音色怡人，長時間聆聽也不會令人疲倦。

In fact, we listened to over 30 types of 6SN7s with this unit and loved every minute.

事實上，我們用這部前級試聽超過 30 種 6SN7 ，每分每秒，都樂在其中。

Overall, the VTV line stage is a preamp that you can live with for a very long time, perhaps a lifetime.

一句話， VTV 高電平前級是一部供你長時間享用的前級。也許可以聽足一輩子。

VTV Octal Line Stage ProjectVTV Octal Line Stage Project 真空管樂園八腳管高電平前級真空管樂園八腳管高電平前級 Time for Fun!

NOTE: High voltages are used in this project. Use caution and never work on tube equipment when power is applied.

注意！本設計使用高壓電，接通電源之後，千萬不要組裝真空管器材。 *

注意！本設計使用高壓電。組裝真空管器材，必須先切斷電源。

VTV assumes no responsibility if you do something careless or stupid while building or using this line stage.

組裝、使用本前級時，如因大意、魯莽而導致財物損失或人命傷亡， VTV 恕不負責。

Canon PowerShot S90Canon PowerShot S90 Time for Fun!

PowerShot S90 is slim, lightweight and compact with the metallic black camera body. The f/2.0 bright lens is equipped to provide a unique shooting effect.

採用黑色金屬外殼的 PowerShot S90 機身纖巧，配備特大 f/2.0 光圈高質素鏡頭，為用家提供更獨特的拍攝效果。

Canon PowerShot S90Canon PowerShot S90 The new Lens Control Ring increases the flexibility of ad

justing the settings such as ISO, exposure compensation, etc. Marrying modern technologies with a compact design, PowerShot S90 delivers an unprecedented shooting experience for users.

新增的鏡頭快速控制環設計，能夠靈活地調校各項常用拍攝設定，例如 ISO 感光度、曝光補償等等，纖巧機身配搭完美的拍攝功能，為用家帶來全新的拍攝體驗。

Canon PowerShot S90Canon PowerShot S90 Featuring the new 10 megapixel High Sensitivity CCD im

age sensor, Dual Anti-Noise System can be achieved in co-operation with the stunning computing speed of DIGIC 4 Digital Image Processor, Noise can be reduced dramatically even shooting at night or dark environment.

配備最新的 1,000 萬像素高感光度 CCD 影像感應器，結合 DIGIC 4 數碼影像處理器的極速運算能力，達致雙重雜訊抑制系統，能夠大幅度抑制雜訊，於夜間拍攝相片時同樣展現高質素影像效果，捕捉完美影像。

Canon PowerShot S90Canon PowerShot S90 The new Low Light shooting mode supports the maxim

um ISO speed of 12800* which enables users to capture the precious moment at night.

新增支援最高 ISO 12800* 低光拍攝模式，即使在昏暗環境下亦能記錄完美一刻，攝盡每個日與夜。

END

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