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
|
| [#142] 好聲的探索 I got the Cary SLP-05 line amp from a friend for repair. After I had it fixed, I listened to it for few hours. Unfortunately, I didn't like it much. The sound body is thick and fat. This is so different from the one that I have which is dynamic, energetic, with superb clarity. The line section employs two stages of 6SN7 with capacitor coupling. It has a 10K resistor for anode-anode feedack plus the cathode feedback with 1K resistor. The overall gain is only 4. The THD specification is only 0.1% but it sound good to me. Of course, it is just a cup of coffee or tea. It is the personal taste. Good or bad? It's someone's own judgement. Johnny 最後修改時間: 2025-02-21 05:20:59 |
johnnykmtang 會員70.xxx.xxx.22 |
2025-02-21 05:18 | |
|
|
|||
| [#143] 好聲的探索 I have been using the TEAC UD-501 DAC for few years. I use the Mac Mini for watching YouTube video and I-tune to play my CD albums. Yesterday evening, I tried the Mac Mini's audio sampling rate at 88K, 176K and 352K. I was surprised that the sound quality at 352K is the best. Was I dreaming? Anyway, lots of people still staying with good old 44.1K sampling DAC's. I think the limitation is within their amps which isn't able to perform well with such HD audio. Johnny |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-23 18:32 |
| [#144] 好聲的探索 I also enjoy Youtube in my system though many Audiophiles would condemn our ideas. |
fotheringay 正式會員 78.xxx.xxx.97 |
2025-02-23 20:58 |
| [#145] 好聲的探索 The recent most enjoyable movie for us(rarely me and my wife agree on some movies) is The Gorge. |
fotheringay 正式會員 78.xxx.xxx.97 |
2025-02-23 21:09 |
| [#146] 好聲的探索 A young Japanese violinist recommended by another R33 member. |
fotheringay 正式會員 78.xxx.xxx.97 |
2025-02-23 21:56 |
| [#147] 好聲的探索 My friend lend me the AD1865 DAC board with I output for trial. I connected the I out to my Hammond 1:4 line transformer and terminated with 4.7K load. I verified the audio output at the transformer is flat to 10Khz with the Soundcard Scope program through the USB interface with the DAC. I monitored the output with oscilloscope. The test was very successful. I realized the sound with just the transformer is very smooth, warm and sweet. It is so different from having op-amp's in the signal path. Oh God..... Simple is the best. |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-27 07:01 |
| [#148] 好聲的探索 Here's the 5Khz output from the AD1865 DAC |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-27 07:04 |
| [#149] 好聲的探索 5Khz sine wave output  |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-27 07:06 |
| [#150] 好聲的探索 10K sine output  |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-02-27 07:08 |
| [#151] 好聲的探索 After experimenting the AD1865 DAC, I am back to my good old Wadia X64. I sounds so good indeed. Too bad that the Optical TORX input doesn't work in the unit. I had to use a TORX - Coax adaptor to play the music from the Mac Mini. Johnny |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-01 06:35 |
| [#152] 好聲的探索 I found the following Canary 300B push pull schematic online. After running the simulation, I found that the circuit isn't perfect and there are few adjustment can be made to make it better. So, if you think having the tubes rolling with other brands, I think it is better to know what is better operating points of the circuit. JOhnny  |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-03 06:23 |
| [#153] 好聲的探索 I tested the sine wave output from the TEAC UD-301. Very smooth SINE wave all the way upto 19KHz.  |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-04 16:50 |
| [#154] 好聲的探索 Tested the TEAC UD-301 with sine wave using up sampling of 192KHz. The output was very smooth and steady up to 19KHz without any issue.  |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-04 16:54 |
| [#155] 好聲的探索 Sometimes the sine wave look smooth and perfect, however the FFT of THD+N can help to observe some issues:  |
mcc_2001 正式會員 203.xxx.xxx.234 |
2025-03-04 18:58 |
| [#156] 好聲的探索 How to win an argument over high res audio |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-07 16:48 |
| [#157] 好聲的探索 Thanks for the advice from MCC_2001. Yes, it is very true that by observing the FFT frequency spectrum of the sine wave output will show much more information than the waveform from the oscilloscope. Through the FFT, we can see very small magnitude of the harmonics contents that result from the distorted waveform. I would like to say that the FFT analysis of the sine wave from an amplifier with multiple stages may be confusing due to the cancellation effect between the stages. For example, for a 2 stages single ended amplifier, the first amplification stage would have distortion of 5% but the final output is having distortion of 2.5%. By looking at the final output, the distortion figure is just fine. However, there are many gabages suffled under the carpet that isn't shown in the final output distortion figure. 最後修改時間: 2025-03-09 09:02:27 |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-09 09:01 |
| [#158] 好聲的探索 Here's an example of the distortion figures of the Old Chen KT88 SE amp for the dirver stage and final output.  |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-09 09:04 |
| [#159] 好聲的探索 Hi Johnny, Thanks for sharing the THD simulation of tube circuitry. It is absolutely right to simulate the circuit performance before actual implemetation. Moreover sigle tone THD is useful for static measurement, but for dynamic measurements (i.e music), nowadays, people know that IMD (Intermodulation Distortion) measurements with multi-tone are more realistic. Some standards as shown below such as CCIF, DIN and SMPTE are wildly applied today. Especially for SMPTE, it is important for designing tube power amplifiers' power supply circuit while it is housed in a metallic chassis.  |
mcc_2001 正式會員 203.xxx.xxx.234 |
2025-03-10 11:35 |
| [#160] 好聲的探索 For tube power amplifier, the rectifier circuit usually cause trouble in IM distortion. The rectifier current especially for semiconductor diodes contain fast rising pulse with mains harmonics cover the whole audio band. This current will induce to the chassis and couple to the audio circuit. Below is a Japanese built tube power amplifie that address these issues properly. They used copper sheet metal for some key areas to push the chassis impedance resonance frequency beyond audio band. Also they adopted tube rectifier with chokes for HV circuit. It is effective to lower the intermodulation of mains harmonics and music harmonics.  最後修改時間: 2025-03-10 12:02:43 |
mcc_2001 正式會員 203.xxx.xxx.234 |
2025-03-10 12:01 |
| [#161] 好聲的探索 MCC_2001 ........ excellent information you shared with us. Thank you. Here's more information that I found online:- Standardized IMD Test IMD measurements use a two sine wave test signal consisting of a large amplitude low frequency tone linearly mixed with a high-frequency tone at much lower amplitude. The most common standard is SMPTE/DIN which uses 60 Hz, 7 kHz and a 4:1 ratio (12 dB). https://www.audiocheck.net/testtones_imd.php |
johnnykmtang 會員 70.xxx.xxx.22 |
2025-03-10 14:49 |
