Translation of Technical Hobbies City University of Hong

Translation of Technical Hobbies City University of Hong Kong CTL 3352 Scientific and Technical Translation Ivan Yeung

What is Super Audio CD? SACD 是甚麼？ p p p It looks just like a normal CD, but that’s where the similarity ends. The SACD difference is breathtaking. The difference in sound quality is so great that you have to hear it to believe it! n 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. n 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 audio performance that no other format can deliver. n 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 CD 非同凡響的 CD p Time for fun! n 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, 000 Hz, DSD technology can theoretically reach 100, 000 Hz. n And with a dynamic range of 120 d. B compared to 96 d. B on CD, Super Audio CD goes right to the limits of human hearing and beyond.

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 (設計) p After a dozen years of listening to “peanut tube” preamps using 12 AX 7 s or 6 DJ 8 s, I asked Eric Barbour to design a simple, good sounding octal-based preamp. p 聽了使用 12 AX 7 或 6 DJ 8 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 Project 真空管樂園八腳管高電平前級 p p As many of you know, the reason there are so many “peanut tube” preamps is because these tubes are small and cheap. n 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。 n 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! n By the way, so is their sonic performance.

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p p Miniature dual triode tubes typically have a small soundstage, tinny sound, are subject to microphonics and can be irritating to listen to. n 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。 n 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 6 SN 7, that can still be found for reasonable prices. n 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 6 SN 7。

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p p p The 6 SN 7 typically has a larger soundstage and is super smooth. n 6 SN 7 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. n 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! n The beauty of this line stage is that you can experiment with the literally dozens of 6 SN 7 s types to get exactly the sound you want.

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p p The circuit design of this project is a classic cathode follower driven by a gain stage. Two 6 SN 7 s are used, one per channel. n 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 6 SN 7， 全機共用兩支。 Overall gain of the line stage is about 12, which should be adequate for most applications. n 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 Project 真空管樂園八腳管高電平前級 p p It is possible to use this preamp with some solid-state power amps, but not all. n 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 5 Y 3 GT tube rectifier is used in this design, (Figure 1), because tube rectifiers add more “magic” and 3 D to the music when compared to typical cheap silicon diodes. n 本設計採用 5 Y 3 GT 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 Project 真空管樂園八腳管高電平前級 p p With this transformer, you could also use a 5 V 4 G, but do not use a 5 U 4, because the filament current is too high. n 用這個變壓器，你也可以用 5 V 4 G 整 流，但別用 5 U 4，因為它需要的燈絲 電流太高了。 DC heater power is derived using Schottky diodes. n 燈絲直流電源由史卓基 (Schottky) 二極管提供。

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p Time for fun! n In order to keep hum to a minimum, copious amount of filter capacitance were needed to keep hum below the 1 millivolt level.

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p p The power transformer is a Hammond 270 BX (550 V C. T. , 5 V@2 A and 6. 3 V@2 A) which allows for a 370 V plate voltage on the 6 SN 7 s. n 電源變壓器型號為漢蒙 270 BX (550 V 中間抽頭, 5 V@2 A, 6. 3 V@2 A)，可 為 6 SN 7 供級 370 V 屏壓。 Higher voltages make the tube more linear and more “exciting” sounding. n 電壓愈高，管子線性愈佳，聲音愈生 動刺激。

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p p The power supply schematic, (Figure 1), also shows how to wire this amp for 12 SN 7 s or 12 SX 7 s if you desire. n 如果想採用 12 SN 7 或 12 SX 7 ，圖一的 供電線路圖亦表示了接線方法。 Time for Fun! n Figure 2 shows one side of the line stage and indicates all component values. n Note that the line stage has switching for three inputs.

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p p We used an old Dynaco PAS-3 selector switch for this task, but you can use a higher quality gold or silver contact switch. n 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@650 V. n 交連電容用了 0. 4µF@650 V 的超音 油浸銀箔電容。

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p Time for Fun! n These caps are clear, deep and huge sounding. p The volume control is a Noble dual 100 K type. n 音量控制旋紐是貴族牌的雙 100 K 類 型。

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p p Performance was improved significantly when we installed a Gold Point dual 100 K stepped attenuator. n 當我們安裝了金點雙 100 K 級進衰減 器時，聲音表現明顯提高了。 Adding the Gold Point cleaned up the sound and reduced any mistracking of the channels. n 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 Project 真空管樂園八腳管高電平前級 p Time for Fun! n This preamp is a super smooth sounding unit and is very easy to listen to for extended periods without listener fatigue. n In fact, we listened to over 30 types of 6 SN 7 s with this unit and loved every minute. n Overall, the VTV line stage is a preamp that you can live with for a very long time, perhaps a lifetime.

VTV Octal Line Stage Project 真空管樂園八腳管高電平前級 p Time for Fun! n NOTE: High voltages are used in this project. Use caution and never work on tube equipment when power is applied. n VTV assumes no responsibility if you do something careless or stupid while building or using this line stage.

Canon Power. Shot S 90 p Time for Fun! n Power. Shot S 90 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. The new Lens Control Ring increases the flexibility of adjusting the settings such as ISO, exposure compensation, etc. Marrying modern technologies with a compact design, Power. Shot S 90 delivers an unprecedented shooting experience for users. Featuring the new 10 megapixel High Sensitivity CCD image 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. The new Low Light shooting mode supports the maximum ISO speed of 12800* which enables users to capture the precious moment at night.