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| [#4823] 單端胆機同好會 Hello Niceday, Good to know your modification of the LM219 has such remarkable improvement. Wondering what were the mods you did? Johnny |
johnnykmtang 會員70.xxx.xxx.22 |
2025-02-03 11:02 | |
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| [#4824] 單端胆機同好會 Hi Johnny, Take a look on below link https://m.review33.com/forum_msg.php?db=1&tstart=0&s=LM219&topic=93191117231638&number=400 |
WilliamsonAudio 正式會員 182.xxx.xxx.105 |
2025-02-03 11:24 |
| [#4825] 單端胆機同好會 Hi Johnny, nothing new, the 2nd stage ECC99 loaded with cascade CCS as usual(with 1.5K shield between CCS and plate，it does reduce the irritating treble harsh), 1st stage with cathode degeneration, 300B at fixed bias eliminating the bypass cap It was not my 219 modification especially good, but most people would say that original line magnetic 219 being especially dull, slow and muddy......Why? They use loop NFB (either 2+stages loop or self plate to grid loop) I would like to emphasis that using all triode to build single ended tube amp still with loop negative feedback is a failure design that most of the China manufacturers still do loop NFB nowadays If Triode must use loop NFB to work normal then all the experienced audiophiles would not build SET 最後修改時間: 2025-02-03 13:22:14 |
niceday009 正式會員 182.xxx.xxx.201 |
2025-02-03 13:06 |
| [#4826] 單端胆機同好會 Hi Niceday009, Your mods surely would have improvements than the original design. During the past two days, I looked up the schematic of the Music Angel 845 SE power amp for a friend in Germany. He sent me the pictures of his but I could not find any schematics that matches his amp. It is known that the Music Angel built their 845 SE with various circuitries other than their original design. Johnny |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-03 17:19 |
| [#4827] 單端胆機同好會 請各位忍耐我又長氣再講 單端三極直熱胆機係所有擴音機類型中最低效率，用最多電力(因為只可以A類)，自身元件亦特別貴(一隻50W 30Hz 單端牛相當於推挽牛230W重量)，如果唔係揾部真正靚声而去用部声音麻麻單端機就真係嘥錢，嘥電，嘥時間 基本零回輸三極直熱單端機一定有之特徵係 1.細緻高解像力 2.快速 3.中音潤滑立體 4.空氣感强烈， 而SET弱點係要有大型輸出牛(大电感，高磁束飽和)才可以有靚低音 如果你部單端機沒有以上4點，可考慮換機甚至用返有回輸推挽石機就算，唔好再嘥電力，留返D地球电力資源比靚声單端機繼續出靚声 最後修改時間: 2025-02-03 18:20:47 |
niceday009 正式會員 182.xxx.xxx.99 |
2025-02-03 18:04 |
| [#4828] 單端胆機同好會 今日收到兩位朋友發呢張facebook相，其中一位係丽磁219机主但佢都表達219唔靚声，Facebook 帖主只係將網上代理及音响寫手那些讚美丽磁219文章放入facebook 呢件事覺得好可怕，219呢部机我最少遇過十幾個機主对佢声音不滿，都係話佢朦夾慢声音唔清晰，而我自己曾經都買咗部219，確認佢声音唔多掂 但係国内及国外代理及音响寫手不停用文章讚美部219, 其用心只不過為賺錢，果D代理商聽過咁多款機應該分別出好声同衰声，為賺錢不惜㩒住良心, 唔靚声吹噓到靚声  最後修改時間: 2025-02-06 22:34:25 |
niceday009 正式會員 218.xxx.xxx.220 |
2025-02-06 22:27 |
| [#4829] 單端胆機同好會 另外有位網友問全段無負回輸声音高速，會唔會影响D慢歌表現 我理解係，隻歌表現是快是慢係應該在原本錄音已定，部amp是應該忠實原本錄音本質，一部可以行450kM嘅日產GTR 亦可以慢駛入女人街，但係一部國產QQ最高速是140kM, 可以同GTR一樣慢駛入女人街，但係放入跑車賽道就只有食塵 即係話amp追求高速度才对，慢速低性能amp週街都係，原裝丽磁就係慢速amp代表 |
niceday009 正式會員 218.xxx.xxx.220 |
2025-02-06 23:01 |
| [#4830] 單端胆機同好會 数码变频发电机，有冇人用緊  最後修改時間: 2025-02-08 16:28:10 |
niceday009 正式會員 218.xxx.xxx.220 |
2025-02-08 16:22 |
| [#4831] 單端胆機同好會 用電油的小型gen set, PQ更差，停電時用來頂一頂，金城班掘地工友先會用！ |
LaLaLam 會員 218.xxx.xxx.249 |
2025-02-08 16:34 |
| [#4832] 單端胆機同好會 日夜PQ差別大，其實最好找供電的utility幫忙,如果理句充分是免費的，有一Report例子如下:0000-0600時間 PQ 最正，音質最好，其他時間想好都幾難！  最後修改時間: 2025-02-08 17:07:52 |
LaLaLam 會員 218.xxx.xxx.249 |
2025-02-08 17:02 |
| [#4833] 單端胆機同好會 Hello LaLaLam, I learned something new from you regarding "voltage and current unbalance factor". Here is what I found from google search:- https://voltage-disturbance.com/power-engineering/current-unbalance-causes-effects-and-protection/ What I understand is the balance between the 3 phase power lines in voltage and current. I did monitor the 120Vac mains voltage waveform with my oscilloscope. The waveform supposed to be pure sine wave. The oscilloscope showed the mains waveform was distorted. Few of my friends are using isolating transformer, power plant, and pure sine wave inverter for their amplifer and turntable. They said there are improvements after using them. 最後修改時間: 2025-02-08 17:30:29 |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-08 17:29 |
| [#4834] 單端胆機同好會 The mains isolation transformer in this case is acting as a bandpass filter, however in some measurement reports, it does not show a significant improvement on mains harmonics under 50th orders.  |
LaLaLam 會員 218.xxx.xxx.249 |
2025-02-08 18:41 |
| [#4835] 單端胆機同好會 The current/voltage harmonics are very difficult to mitigate. Some industrial sectors apply so called APF "active pf correction" to generate and inject inverted harmonics to correct the mains PQ.  |
LaLaLam 會員 218.xxx.xxx.249 |
2025-02-08 18:58 |
| [#4836] 單端胆機同好會 Sometimes my apartment also come across the bad harmonic power line. Sound thinned out and bass reduced. ＞＞bandpass filter Can it be improved by using inductor plus cap? And the picture of the portable generator shown in the following post is called inverted generator, does it match your APF? 最後修改時間: 2025-02-08 19:25:03 |
niceday009 正式會員 218.xxx.xxx.220 |
2025-02-08 19:11 |
| [#4837] 單端胆機同好會 Active Power Filter mainly adopt fast switching capacitor banks to tackle harmonic current.  |
LaLaLam 會員 218.xxx.xxx.249 |
2025-02-08 19:35 |
| [#4838] 單端胆機同好會 國內呢款inverter gen set係要入電油，發電機出dc,然後用開關PWM變頻出正弦波，頻率穩定度和harmonics contents未達emc標準,also the output is not synchronized with mains frequency that will generate beat frequency on audio gears ，definitely it is not APF。  |
LaLaLam 會員 218.xxx.xxx.249 |
2025-02-08 20:14 |
| [#4839] 單端胆機同好會 Hi LaLaLam, Thank you for your information on the power distortion. The portable power station claimed they produce pure sine wave. Wondering how good it is. I once worked on an old "power plant" made by PS Audio. It has a sine wave generator circuit. The sine wave signal then feed to a transistor OCL amp to generate 120Vac output. |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-08 21:46 |
| [#4840] 單端胆機同好會 Portable power station  |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-08 21:47 |
| [#4841] 單端胆機同好會 Hi Johnny, To deal with mains harmonic distortion, the first thing is to perform some measurments as shown below: Mains voltage in blue using differential probe and a power amplifier's mains current with ac current probe. The pulse shape current waveform is very common for all ac/dc rectifier circuit and it makes the mains sine wave become flat top distorted.  |
LaLaLam 會員 218.xxx.xxx.243 |
2025-02-09 07:34 |
| [#4842] 單端胆機同好會 Both PS Audio and Accuphase's power regenerators adopted analog power amplifier to deliver mains power. Accuphase's seems using APF concept to correct the flat top sine wave problem.  |
LaLaLam 會員 218.xxx.xxx.243 |
2025-02-09 07:41 |
