兩聲道
CD機 | MD機 | SACD機 | DAC | CAS | 合拼擴音機 | 前級擴音機 | 後級擴音機 | 接線 | 喇叭線 | 揚聲器 | 耳機 | 耳機擴音機 | LP產品 | 膽機產品 | 開卷式錄音機 | 音響配件 | DIY音響 | 電源 | 家庭影院
電視機 | 投影機 | 錄影機 | DVD影碟機 | Blu-ray影碟機 | 多媒體播放器 | 機頂盒 | 多聲道擴音機 | 多聲道揚聲器 | 多聲道影音組合 | Mini音響組合 | 重低音揚聲器 | 輔助設備 | 同好會
同好會 | Accuphase | B&W | Burmester | Denon | Jadis | KEF | KRELL | Luxman | Marantz | Nuforce | OPPO | Pioneer | TEAC | WEISS | News
News | Blog | 其他
其他 | 所有 |
| 影音天地主旨 ﹝請按主旨作出回應﹞ 上頁 下頁 首頁 尾頁 | 寄件者 | 傳送日期
|
| [#9725] Leak Club for Leakies or Leak user ^+++++++^  |
dd845 正式會員219.xxx.xxx.124 |
2006-01-31 16:34 | |
|
|
|||
| [#9726] Leak Club for Leakies or Leak user KT66 is the designator for a vacuum tube introduced by Marconi-Osram Valve Co. Ltd. (M-OV) of Britain in 1937. The KT66 is the direct descendant of the "Harries Valve" developed by British engineer J. Owen Harries and marketed by the Hivac Co. Ltd. in 1935. Harries is believed to be the first engineer to discover the "critical distance" effect, which maximized the efficiency of a power tetrode by positioning its anode at a distance which is a specific multiple of the screen grid-cathode distance. This design also minimized interference of secondary emission electrons dislodged from the anode. EMI engineers Cabot Bull and Sidney Rodda improved the Harries design with a pair of beam plates, connected to the cathode, which directed the electron streams into two narrow areas and also acted like a suppressor grid to absorb some secondary electrons. The beam design was also undertaken to avoid the patents which the giant Philips firm held on power pentodes in Europe. Because this overall design eliminated the "tetrode kink" in the lower parts of the tetrode's voltage-current characteristic curves (which sometimes caused tetrode amplifiers to become unstable), M-OV marketed this tube family under the sobriquet "KT", meaning "kinkless tetrode". A number of different KT tubes were marketed by M-OV thereafter. Some were versions of existing American beam tubes or European power pentodes, such as the KT66 (6L6), KT77 (EL34) and KT63 (6V6); while others were unique to the KT series. Although the RCA 6L6 of 1936, the result of a license agreement between RCA and M-OV, was the first true "beam power tube" on the market, the later KT66 became almost equally famous. The two tubes were nearly interchangeable, except that the KT66 was much more rugged and capable of tolerating overvoltages and overcurrents that would destroy a 6L6. The KT66 was very popular in European radios and audio amplifiers. It was the standard output tube in the classic Quad II (1952, a version of which is still being manufactured today) and Leak TL/12 (1948), both among the earliest British hi-fi amplifiers. Because of their excellent electrical characteristics and overload tolerance, KT66s are desirable to some guitar players for use in guitar amps in place of 6L6GC (readjustment of the amplifier's bias is necessary). M-OV ceased glass vacuum tube manufacture in 1988, yet their old audio tube types have become valuable collectibles. As of 2004, an old M-OV KT66 (bearing the official "Genalex" marketing brand that M-OV used outside the UK), unused in its original carton, can easily bring US$250. The trade in KT66s is so intense that at least two copies are being manufactured; one at Reflektor Saratov in Russia, and one at Liuzhou in China. These modern tubes are often packaged in counterfeit "Genalex" boxes and sold as being the real thing. |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 17:04 |
| [#9727] Quad II Early history The company was founded by Peter J. Walker in 1936 in London, and was initially called S.P. Fidelity Sound Systems. In 1936 the name was changed to the Acoustical Manufacturing Co. Ltd. The company moved from London to Huntingdon in 1941 after being bombed out of London in World War II. The company initially produced only PA (Public Address) equipment but after the war they began to produce equipment designed for use in the home as a result of the rising demand for high quality domestic sound reproduction. Within a few years the company had transitioned almost entirely to manufacturing models for the home audio market. [edit] Pioneering Audio Products The QA12 amplifier was the first domestic product manufactured by QUAD and was released in 1948. The QA12 was a mono valve (tube) amplifier that had a power output of 12 watts. The QA12/P, released at the same time, was the same as the QA12 except that it had a built in pre-amplifier (control unit). This unit became renowned for its high quality reproduction and was used by the BBC. The origin of the word ‘QUAD’ is found in the ‘Q.U.A.D. I’ amplifier and control unit released in 1950. The generally accepted meaning for the acronym "Q.U.A.D." is "Quality Unit Amplified Domestic." The QUAD I was a 15 watt mono amplifier and was sold complete with control unit (incorporating volume and tone controls) for 33. The QUAD I was produced until 1953. In 1953, QUAD produced the QUAD II amplifier. This 15 watt mono amplifier along with the accompanying QC II control unit cost just 34.10s when new. The QUAD II was made until 1970. In its long production run, and even against modern competitors, it is regarded as the crème-de-la-crème of valve amplifiers by many valve enthusiasts. A new version, the Quad II forty, uses bigger output valves (KT88s instead of KT66s) to produce a higher output power and is still manufactured to this day. Following the development of stereo records in 1958 the QC 22 control unit was developed and released in 1959. This was a stereo control unit that was designed to be used with a pair of QUAD II mono amplifiers. Throughout the QUAD II production run, the company also produced AM and FM tuners designed to be used with the QC II & 22 control units. In 1957, the company made history when they released the world’s first production electrostatic loudspeaker – the ESL-57. The ESL-57 uses ultra-thin stretched mylar as the main component of its drive units. The mylar sheet is coated with a mildly electrically conductive paste and is sandwiched between 2 stators. A very high voltage is applied to the mylar and to the stators. By varying the charge on the stators the mylar will be set in motion, thus producing sound. Two bass panels flank one treble panel to provide full range sound. This ingenious approach to speaker design afforded certain advantages over traditional paper or plastic/composite cones. Primarily, the lightweight nature of the mylar, and the linearity of its movement allows for very low distortion. Compared to traditional box-based speakers with cone drivers, the ESL offers a level of transparency and faithfulness that is without peer, especially in the midrange. The lack of bass below 40Hz and lack of treble extension above 17,000Hz are the only significant weakness. When matched with the QUAD II amplifier, a well-maintained pair of ESL-57s will favourably compete with modern designs costing over $5000US. The critical and popular success of the ESL-57 and QUAD II earned QUAD the reputation of having "the closest approach to the original sound."  |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 17:09 |
| [#9728] Quad II wow..."割套"(Quard II). Still remember its very muscial tone.... (thanks brother albertino lending his pair and the 4 x GEC KT66 to me for audition) |
lym 正式會員 219.xxx.xxx.4 |
2006-01-31 17:13 |
| [#9729] Leak Club for Leakies or Leak user TONBRIDGE AUDIOJUMBLE ------------------------------------- John Bell just posted this on the Yahoo! Spendor forum - I thought it may be of interest to a wider audience. Note that John will have a good collection of classic turntables, valve amplifiers, and speakers on his stand plus of course Andy Whittle (ex-Rogers and Exposure). Dave. http://www.audiojumble.co.uk/ ------------------------------------------ Richard If you can go, you can act as a reporter :-) John  |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 18:16 |
| [#9730] Leak Club for Leakies or Leak user It all came flooding back, I was like a kid in a candy store |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 18:20 |
| [#9731] Leak Club for Leakies or Leak user The Audiojumble -- a flea market for treasure looking. I got a 5-piece Quad II setup exactly two years ago at only 450 pounds. |
johnnywalker 正式會員 61.xxx.xxx.111 |
2006-01-31 19:06 |
| [#9732] Leak Club for Leakies or Leak user The Audiojumble venue is very near the Tonbridge Railway Station. Besides, there are some parking spaces. Of course, only early birds can get the betting parking positions. |
johnnywalker 正式會員 61.xxx.xxx.111 |
2006-01-31 19:08 |
| [#9733] Leak Club for Leakies or Leak user Richard If you can go, you can act as a reporter :-) --------------------------------------------------- John, I love to go but what a coincidence that I shall return on the same date. My plane will leave at Birmingham (not London)! Not as simple as going to the Wanchi HiFi show. Would need to drive over 7 hours and stay a couple more days in the UK (and miss more lessons). Seems to be infeasible. |
rcwy 正式會員 82.xxx.xxx.28 |
2006-01-31 19:29 |
| [#9734] Leak Club for Leakies or Leak user I got a 5-piece Quad II setup exactly two years ago at only 450 pounds. ------------------------------- JL, JK I guess JL are lucky for he went to the Tonbridge 2 years ago. Nowadays professional 2nd hand stuff sellers know they can sell much higher at eBay and automatically ask for more in any flea market. Anyway there should be good fun going the the Tonbridge. It is a shame not able to go. Don't know if Paul Whatton will be there this year. He seems very busy. |
rcwy 正式會員 82.xxx.xxx.28 |
2006-01-31 19:58 |
| [#9735] Leak Club for Leakies or Leak user Definitely. Two years ago, there were two or three hundred ads on magazines such as Hifi orld. Some old and conservative guys still preferred to sell their stuff in the traditional way. Now, we can only find some ads sporadically. |
johnnywalker 正式會員 61.xxx.xxx.111 |
2006-01-31 21:16 |
| [#9736] Leak Club for Leakies or Leak user The internal was not re-sprayed. I specifically ask them not to. There are some grounding connections and I rather keep it that way rather than scratch the paint again. ------------------------------------------ YC's decision is correct. If the inside chassis were sprayed, there will be poor grounding though the internal will look beautiful. _______________________________________________ It was no problem, I had measured that there were no resistances between circuit and chasiss ground, and I also found that S/N better than previous..^___^  |
dd845 正式會員 219.xxx.xxx.124 |
2006-01-31 21:54 |
| [#9737] Leak Club for Leakies or Leak user there will be poor grounding though the internal will look beautiful. ______________________________________________ Sure, internal looks beautiful..^___^ |
dd845 正式會員 219.xxx.xxx.124 |
2006-01-31 21:57 |
| [#9738] Leak Club for Leakies or Leak user I am going to start my Opened Frame mission after CNY..^^  |
dd845 正式會員 219.xxx.xxx.124 |
2006-01-31 22:00 |
| [#9739] Leak Club for Leakies or Leak user .  |
dd845 正式會員 219.xxx.xxx.124 |
2006-01-31 22:04 |
| [#9740] Leak Club for Leakies or Leak user my Opened Frame mission ---------------------------------- Another pair :-) |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 22:20 |
| [#9741] Leak Club for Leakies or Leak user The internal was not re-sprayed. I specifically ask them not to. There are some grounding connections and I rather keep it that way rather than scratch the paint again. ------------------------------------------ YC's decision is correct. If the inside chassis were sprayed, there will be poor grounding though the internal will look beautiful. _______________________________________________ It was no problem, I had measured that there were no resistances between circuit and chasiss ground, and I also found that S/N better than previous..^___^ ========================================== So, finally the big boys made up their mind to spray the inside after respraying the outside of the chassis. The problem of grounding can be overcome by sanding off the paint at where the chassis is to be grounded. Should not be a big deal. But this goes beyond the original wor (i.e. better than)! DD- Where are the pieces of plastic rulers? I can't find them. Why didn't ask the car-body workshop to weld and repair the chassis instead? Should be worthwhile to do. |
rcwy 正式會員 82.xxx.xxx.28 |
2006-01-31 22:29 |
| [#9742] Leak Club for Leakies or Leak user Not as clean as DD's :-)  |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 22:30 |
| [#9743] Leak Club for Leakies or Leak user Where are the pieces of plastic rulers? I can't find them. ------------------------------------------- Richard The rulers showed up several times already :-)  |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 22:31 |
| [#9744] Leak Club for Leakies or Leak user Why didn't ask the car-body workshop to weld and repair the chassis instead? -------------------------------------------- I guess they will do it for you if you pay more :-) |
Gingers 正式會員 221.xxx.xxx.200 |
2006-01-31 22:32 |
