Welcome
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- Written by 站長Chris Chang
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Welcome to my website dedicated to vacuum tube amplifiers and high-efficiency speakers
Welcome to my website. This site was mainly in Mandarin and I plan to translate some of the articles to English. The progress is slow. I use Microsoft translation service for the articles that are not translated by human yet to form a framework. The translation result was horrible. But what can you complain for something that's free?
50 single-ended amplifier overhaul--New wine in an old bottle
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- Parent Category: Audio frequency circuits-en-gb
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Finally the work on his pair of amplifiers is done. Let's have a look on what's different..
This is the new look. The places that use to hold UTC chokes are replaced by load-inductors and interstage transformers.
Something new under the sun--Longitudinal Direct Coupled Amplifier
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- Parent Category: Audio frequency circuits-en-gb
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Vacuum tubes have been invented for nearly 100 years. Honestly all possible circuits configurations are almost exhausted. About fifteen years ago, following the rise of internet, there used to be an electronics Periodical called theTube CAD Journal where many innovative circuits were published. Tube CAD Journal seems to cease publishing since 2003. Around the same time period another paper based Periodical, the Vacuum Tube Valley, stopped publishing after the chair editor Charlie Kittleson passed away. There were a total of 20 issues of Vacuum Tube Valley with good materials on vacuum tube circuits. Since then it was really quiet. That's why my eyes were wide-open when I see the Longitudinal Direct Couple Amplifier. In the rest of the article I use the acronym LDCA to represent the name of this circuit.
Longitudinal Direct Couple Amplifier, publish granted by Chris Strickland
Amoy 寶 landmine – explosion Jiang phishing Rubycon electronic solutions Capacitance
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- Parent Category: misc
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Story, this is the start of model courses:
Single-ended 50 power amplifier modification notes--high negative voltage grid bias circuit
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This pair of 50 SE amplifiers was built by me some 15 years ago. The circuit is very stable and during the years of service there wasn't much problem except one event 3 years ago. The problem was caused by one faulty 80 rectifier where the filament broke and fallen onto one of the plates. It caused a short-circuit from the high-voltage winding of the mains transformer to the ground. I was using a 3A fast blow fuse and the short-circuit current caused by the faulty rectifier wasn't high enough to blow the fuse. Consequently the transformer heated up and eventually blew up the winding. The transformer was carefully built by James Audio but apparently it can't withstand such high current for a long time. Ever since that event I became extremely cautious about safety. If you ever built a tube amplifier, ask yourself a question whether or not the amplifier will survive when a rectifier goes to short circuit. This is a common problem for the rectifiers with hanging filaments. And many people including me believe tubes with hanging filaments sound better.
TEAC VRDS 25 repair note-replacing the driving belts
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- Parent Category: Digital audio source and Digital Signal Processing
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I bought this TEAC VRDS 25 CD player at ebay about 15 years ago when I did my graduate study at University of Pennsylvania in US. I listed this CD players on the internet for sale a couple times with not so positive experiences. Since I don't need money that bad so I just keep it on the shelf. I rarely turn it on after I start messing around with my Studer A725 CD players.One day my friend Xiang visited me and we tried to compare many CD players. In the end we decided to give the VRDS 25 a try but the CD tray didn't open when plugged in. When the open button was pressed nothing happened except a motor noise. Looks like spending some money is inevitable.
As usual, I started by searching the web for discussions and service manuals. From the discussions I learned that it's most likely the belts. Then I started searching replacement belts and after 3 weeks I received a bag as pictured. I was almost saying the F word when I got this bag. The belt can be easily found at a local electronics store at around USD$1 and I paid EUR$10 for these. Let's just hope these imported belts last longer.
Germany sent skin brought in the future, but unfortunately does not mean Germany manufacture
Meets the enthuastic boss--Tokugawa professional speaker encloure manufacturer
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- Parent Category: loudspeakers-en-gb
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Recently starting with those I'm speakers such as JBL 4312A or Tannoy Devon box are two light, want to try to try to see if 較 堅 solid box had a little difference how big is the Club Med. NET hahawer a number of information materials on the road, together with Mr Zhang 俠, who built Council, start I'm 樺 Jia wood Board manufacture speakers feel Hobby. With 樺 wood Jia Board when about 鍵 Word, in Web Shang found two three home manufacture made speaker of facility business has Russian Rome Republika 樺 wood Jia Board can choose liquid, this future has Bible duel set Board burgeoning a between bit in Taichung promote thing manual furniture of 鄭 Mr manufacture for, who know 鄭 Mr told 樺 wood Jia Board deficiency 貨, to, a real months, in this a real months station long cannot intended to Web road release now has a between called de chuan speaker of facility business 蠻 interesting of, spent has some when between put Web Road found of information material see over a again, also playing has both pass TV said links Luo 負 Ze people displayed zone chuan Mr, Discuss the theoretical stand long 訂 box specification. 認 Mr Chen surname because of long grass of Seattle is not provided by 專 operating, short little lot, Zhan Zhang likes this kind of ran briskly for one boss, is displayed and the boss of approximately one day to his facility when Gou-pass.
Qi boom in 負 Ze man the displayed zone in Sichuan and decrepitude of Mr Zhan Zhang
WE REP series transformers measurement results as promised
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- Parent Category: audio frequency transformers
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This article is WE REP series change pressure device and CD match change pressure device 雜 談of 續 set, in Shang article articles here, station long using PSPICE die 擬 WE 120C change pressure device received in CD sing Pan stub Qian class zoom device of between when into "sound quality improved device" of frequency rate 響 ying, promote die 擬 get of results theory is unless CD sing pan of input out impedance enough low (<50 Ohms), whether entering into 120C this some 繞 team sense volume not to 1H of change pressure device Club Med production health many low frequency failure reduce. Here in this article stand long fact international measured 寶 Mu Xuan Xu, the teacher offers WE anform total measured completely 120C, 120D, 94E, 94H, six 顆 94N stub 173E.
WE REP series outside anform views
Study of JBL 4310,4311 and 4312 speakers crossover design
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- Parent Category: loudspeakers-en-gb
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In the previous article we went through the history of the famous JBL 431x series monitor speakers. This series of speakers share a lot of debates over the years. The supporters think they are a precise sounding piece of equipment while the objectors think they are noisy and harsh sounding. In this article I tried to use a modern speaker design point of view to investigate the pros and cons of the design of the 431x series. When these monitors speakers were first introduced in the 60s they are considered the state-of-art. There is a reason that these speakers stayed in many recording studios for so many years. But are they still capable of delivering the elements required for a recording studio 50 years? I don't have an answer for it.
JBL 4312e, source: The Internet
JBL 4312C reconstruction project a.a
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This is the San Francisco article 1999 miniWatt, when standing at the beginning of long hand there are Yes JBL 4312C, how Ting is not full, and finally begins to put the box down. Ten tired years later, then head back to see this article, Wikipedia a lot of CUO Wu, less 輕 when his adult memories in my eyes. Friends name when years have a real Web model courses University model courses, also removed boxes, used fruit stand long threes on Altec, why disappoint friends catch this Web Po, do not know how this Web 4312C the last finish reset? This why I'm this first Web friends deeply apologetic. Edge International Club Med recently, reading some JBL 4312 series article, or a Yes 4312A 剛 good and quite Club Med to get, while quite sort out information material, and Yes this Web there is individual accountability.
Tittle-tattle on JBL 4310, 4311 and 4312 series studio monitor speakers
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- Parent Category: loudspeakers-en-gb
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Despite many people don't like the sound of the JBL431x speakers (too rough, too harsh, doesn't sound like other larger JBL monitors.), the achievement of this series of speakers and it's sibling L100 is unquestionable. This series of speakers are being sold for more than 50 years and even today you can still find them in service in a recording studio. It's hard to find a second speaker model that shares this kind of success.
Left to right: 4311, L100A, L100, 4310. Source: the Internet
The consumer cannot bear the fact – 談 speaker measured amount of traps
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- Parent Category: loudspeakers-en-gb
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Gifts thanks to tone-輩 響 introduced to essential operating big brother Zhan Zhang 導 Horn 擺 in the future, the eldest brother 順 Zhan Zhang taught him set this research alone for those years 擺 del Carmen Horn counterpoint, an expert shot, sure then different 響, property conditions of Zambia 擺 sound of sudden, long Club Med in another article. Lam don't Qian to brother requirements station long put Horn 擺 bit 後 of measured General results fruit sent to he, station long in finishing measured General results fruit when, by in since promote open began using Praxis up, by volume to frequency rate 響 Ying are not is flat, has little 懷 suspected is not station long of volume measured way or is Praxis Department system has question problem, in is Shang Web wants to find about don't people measured General of Bible these, accident release now this article articles, http://www.audioholics.com/education/loudspeaker-basics/audio-measurements , to has station long is big of 幫 help, this paper author is Gene DellaSala, Gene is a reflection of Audioholics NET Office who built Council: temporary staffing ･ English OK friends look at the original, most of this article refer to Gene, measured information modified into long Tannoy Gold 15 ".
Precision true horns measured? That is the fact you can't afford!