作者: fast20181 時間: 2019-10-13 11:39 標題: * 無源前級 三級 - 貴 中 平 * 你買左未
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作者: tskso 時間: 2019-10-13 12:02
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作者: 118205 時間: 2019-10-13 13:36
一堆咸水草
作者: fast20181 時間: 2019-10-13 14:26
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作者: tskso 時間: 2019-10-13 14:29
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作者: fast20181 時間: 2019-10-13 15:08
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作者: pallee 時間: 2019-10-13 15:18
本帖最後由 pallee 於 2019-10-13 15:33 編輯
回覆 1# fast20181
I am on negative side of it.
First of all, this guy knows nothing about electronics (really nothing). He is paid for promotion purpose. He tells myths only.
Powerless pre-amp is just coupling transformer. Basically it is unnecessary. All these features (EMI removal, filter) are better done in power amp (not externally). Inversely, adding a powerless pre-amp may deteriorate the signal transfer (lower THD+N, lower S/N, more noise, more phase shift).
Powered pre-amp has a unique function. It corrects the gain curve across the audio frequency range and makes it a straight line. Also, it helps to normalize the loudness and provides a better volume control. It is useful (needed) in the past (e. g. Vinyl).
In digital world, it is less useful as audio signal after DAC is already gain linear and normalized. And nowadays it is more popular to do volume control on the signal (before amplification), not on the output (after amplification). That makes the gain stable (more linear, more balanced, less noise, less error) and avoids distortion (due to unstable transistor operation). In expensive product, you can find the volume control chip (after DAC chip, before amp). In cheap product, it just programs the DAC chip for volume control.
But sometimes it is still good to add a powered pre-amp between DAC and power amp for more accurate signal or dedicated frequency band adjustment (hardware EQ).
作者: pallee 時間: 2019-10-13 15:24
If the music source (DAC, CAS, DAP) has volume control, just plug it to the power amp. That is.
The simpler, the better.
作者: pallee 時間: 2019-10-13 15:30
透過一對由鈹膜合金製造的交連變壓器進行音訊放大，毋須經過膽管或原子粒，令音色更乾淨自然，將頻率響應提升至10Hz~45,000Hz
complete nonsense
作者: tskso 時間: 2019-10-13 15:40
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作者: tskso 時間: 2019-10-13 15:44
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作者: pallee 時間: 2019-10-13 15:52
回覆 10# tskso
In electronic design, it is a principle. After the signal is created, there is no chance (no place, no way) to "enhance" it.
All we can do is to minimize the loss, noise and deterioration on the signal (during signal transfer, signal processing).
But there is an exception, Class D amplifier. Class D involves re-sampling, pulse amplification and signal re-construction (LPF). There is chance to achieve a better output signal in terms of ratings (higher S/N, less noise, less phase shift) by using signal sharpening filter.
However, I don't like class D for personal reason.
作者: tskso 時間: 2019-10-13 15:57
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作者: tskso 時間: 2019-10-13 16:09
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作者: tskso 時間: 2019-10-13 16:15
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作者: tskso 時間: 2019-10-13 17:55
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作者: fast20181 時間: 2019-10-13 18:16
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作者: tskso 時間: 2019-10-13 18:18
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作者: pallee 時間: 2019-10-13 18:35
本帖最後由 pallee 於 2019-10-13 22:21 編輯
回覆 17# fast20181
You are deeply falling into myths. But no change is required.
When you love something, just enjoy it. No need for a reason.
Everyone can enjoy music. You don't have to know Maths, science and electronics. Like the guy you mentioned, he knows nothing. But he spreads myths. I suggest you not to do that.
作者: tskso 時間: 2019-10-13 18:42
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作者: tskso 時間: 2019-10-13 18:54
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作者: pallee 時間: 2019-10-13 22:06
本帖最後由 pallee 於 2019-10-14 02:09 編輯
回覆 1# fast20181
其實你很喜歡 HiFi, 不如正式去讀電子學
At HK VTC, basic electronics studies can be finished in 2 years. It is mainly on component theory and circuit design. No high level Maths is required (basic Calculus is OK, no calculation is involved). Then you may choose a special subject (e. g. signal processing or microwave) if you are still interested in it. At that time, high level Maths is required (infinite series, FFT).
If you know electronics, you will not believe in those myths.