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| [#21] TACT 的數碼放大器是什麼 ? SDA2175 is Semi-digital power amp. Analog input -＞ PWM -＞ Speaker. Power amp only. M2150 - Digital Integrated Amp. Digital Input (PCM) -＞ PWM -＞ Speaker. Integrated Amp. http://www.hkheavs.com/hkheavs_content.php?s=reports/20040401&c=index&m=66040528014901 Photo: TacT Audio SDA2175 Semi-Digital Power Amplifier  |
Sam 網主 |
2004-12-02 21:54 | |
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| [#22] TACT 的數碼放大器是什麼 ? How can PWM signal output to speaker directly? I don't think speaker can convert PWM signal to analog sound wave... 拳拳小書僮,do u know what is PWM?please clarify it b4 u say... |
wwwhk 正式會員 203.xxx.xxx.179 |
2004-12-02 22:05 |
| [#23] TACT 的數碼放大器是什麼 ? wwwhk: you are right, PWM signal cannot drive the speaker directly, the actual meaning is PWM signal to control the current to drive the speaker. We will correct the wording of our review. |
Sam 網主 |
2004-12-02 22:49 |
| [#24] TACT 的數碼放大器是什麼 ? This book gives a basic understanding of PWM. http://www.embedded.com/story/OEG20010821S0096 |
Sam 網主 |
2004-12-02 22:53 |
| [#25] TACT 的數碼放大器是什麼 ? wwwhk, TacT digital amp takes PCM signal from CD transport and uses proprietary algorithm (EQUIBIT) to convert PCM signal to PWM signal that directly control high voltage, high current DC on and off at very high frequency... essentially, that is PWM power signal... at that stage, it is still digital, the power signal then goes through LC filter before it leaves the amp… that’s it… *** LC filter (passive components) used should be a low pass filter to "smooth" out the signal to prevent damaging the spk... |
wilson. 正式會員 210.xxx.xxx.37 |
2004-12-02 23:37 |
| [#26] TACT 的數碼放大器是什麼 ? I think the problem of the digital amp is the output stage since it needs LC filter to filter out the digital signal. However, the speaker is just like another L+R that would affect the overall filter performance. But the impedance of the speaker would be changed in different frequency and it can not be predicted (too many different speaker and different design in the market). Also the level of the PWM signal can not be adjusted since it should switches between the supply voltage and Gnd to obtain the max efficiency. The only way is to use software to recalculate the PCM weight before convert it to PWM. However, it will decrease the resolution of the signal. Besides, the RF noise generation is the other great issue of this kind of amp. |
DYreal 正式會員 203.xxx.xxx.27 |
2004-12-03 01:20 |
| [#27] TACT 的數碼放大器是什麼 ? Hi DYreal, See my responses below. I think the problem of the digital amp is the output stage since it needs LC filter to filter out the digital signal. ＞＞＞ The LC filter is just a low pass filter to filter out high frequency signal. However, the speaker is just like another L+R that would affect the overall filter performance. ＞＞＞ Most speakers themselves has low pass, high pass and some got band pass filters, too. They are relatively complicated (and thus not easy get good crossovers for speakers) when compared with TacT digital amp LC filter. With that, TacT digital amp possibly is not the bottleneck. In fact, TacT digital amp has digital crossover that one can completely void the need of having crossovers in speakers. But the impedance of the speaker would be changed in different frequency and it can not be predicted (too many different speaker and different design in the market). ＞＞＞ Agree impedance of speakers vary. TacT room correction system (RCS) preamps can easily compensate this buy fine tuning the target curve. Also the level of the PWM signal can not be adjusted since it should switches between the supply voltage and Gnd to obtain the max efficiency. The only way is to use software to recalculate the PCM weight before convert it to PWM. However, it will decrease the resolution of the signal. ＞＞＞ I guess you are referring to volume control and possibly cause loss in digital fidelity? Yes, agree the level of PWM signal cannot be adjusted. But one can directly adjust the DC amplitude instead of altering PWM signal. The result would be no loss in digital fidelity regardless of volume level. Besides, the RF noise generation is the other great issue of this kind of amp. ＞＞＞ So far, TacT digital amp receives very positive feedback about black music background and low coloration. I guess advances in technology might have, to certain extent, overcome RF noise problem in digital amp. *** Thanks for your sharing… Above is just my two cents… ^_^ |
wilson. 正式會員 152.xxx.xxx.187 |
2004-12-03 12:31 |
| [#28] TACT 的數碼放大器是什麼 ? Thanks for your great information about the digital amp. It seems that this is the perfect technique for audio amplifier. Light, slim, powerful..etc. However, there have had only a few product in the market. Can any brother let us have his/her comparison report between tradition amp and digital amp (same grade)? |
DYreal 正式會員 203.xxx.xxx.4 |
2004-12-03 23:59 |
| [#29] TACT 的數碼放大器是什麼 ? wilson. fyi Robert Greene (TAS) once said: "Watch out--the "digital" amps, whatever else is good about them(and there are some things!) tend not to be flat into real-world loads--especially in the top end. Tact Millennium takes off nice flat and even more so with the Sharp, for example." |
kcm 正式會員 218.xxx.xxx.136 |
2004-12-04 10:30 |
| [#30] TACT 的數碼放大器是什麼 ? Hi brothers : what is diffence RCS2.0 /RCS2.0s ? And it's have no analog output,only digital output? THX... |
erichow 正式會員 202.xxx.xxx.72 |
2004-12-07 11:45 |
| [#31] TACT 的數碼放大器是什麼 ? 2.0S是2.0的升級版,最基本2.0 UP-samp,至96. 但2.0S到192,及有12段 EQ. 容易操作很多, |
leroy 正式會員 210.xxx.xxx.219 |
2004-12-07 15:16 |
| [#32] TACT 的數碼放大器是什麼 ? TACT 的2.0S 及2.2X 衹接受 PCM 訊號,如果要玩 AC3, DTS. 一定要用 TCS MKII,但我曾經在我朋友家玩2.2X 看 DVD 十分好玩.頂引啊！ |
leroy 正式會員 210.xxx.xxx.219 |
2004-12-07 15:26 |
| [#33] TACT 的數碼放大器是什麼 ? kcm, yes... if I recall correctly, with LC filter, TacT digital amp will have 2-3 dB dip at high frequency... that's why they suggest to pair it with RCS for compensation if you feel the system is too "dim"... |
wilson. 正式會員 152.xxx.xxx.187 |
2004-12-07 15:46 |
| [#34] TACT 的數碼放大器是什麼 ? DYreal, I am not saying it is perfect... I believe it also has it's own constrains... eg, choice of high quality power switch might be very limited, power quality, conditioning of the high voltage DC, etc... different implementation (digital, analog, diffeent brands, etc...) has its own characteristic... one chose whatever he/she likes is the most important thing... ^_^ |
wilson. 正式會員 152.xxx.xxx.187 |
2004-12-07 15:54 |
| [#35] TACT 的數碼放大器是什麼 ? i believe RCS 2.0S also comes with enhanced measurement algorithm... according to some of RCS 2.0S upgrade users, the new DA board for RCS 2.0S also improved quite a lot... |
wilson. 正式會員 152.xxx.xxx.187 |
2004-12-07 16:01 |
| [#36] TACT 的數碼放大器是什麼 ? Dear all, Do anyone can confirm if DCS2.0s can upsample 24/176 signal? |
e679 正式會員 116.xxx.xxx.7 |
2010-03-20 12:29 |
| [#37] TACT 的數碼放大器是什麼 ? Tact 正 |
tingmoon 會員 219.xxx.xxx.140 |
2025-02-25 12:51 |
