Hyperma对高档线材的嘲笑，是从广告词开始的……

hyperma

一句话：如果是音箱线，考虑的东西只有线径。如果是信号线，则材料和长度就不是重要的，起码对信号传输的影响可以忽略不计。

hyperma

像分布电容、电感这些词汇，都是出现在高频（可不是倒霉的音频信号20千赫哦）放大电路上的，是广播、通信中用的，我无线电学的一般，但是起码知道这些东西不会在简单的音频放大电路上出现，音频放大器，要考虑的是其他的东西，比如……外观、屏蔽、输出电流（可不是一堆晶体管并联就是大电流哦！）、信噪比。

aaronyy

The L, the C and the R
To alter the sound passing through it least, the various parts making up the impedance must have such values, that little or no alteration happens for Audio-frequencies. Interestingly, (for me) Audio-Frequencies means 4Hz - 100kHz in order to guarantee no more than 0.1db deviation at 20Hz or 20kHz.
If we look at the general impedance&#39s in line-level interconnects, we find (usually) that the source-impedance is in the region of a few ohms to a few kilo-ohm. The load impedance ranges from about 10kOhm to about 1MOhm. The input capacitance is mostly very moderate too (100pF or less).
This provides us with some indication as to the relevance of the various electrical parameters that matter.
It seems that as long as the cable dc-resistance is being kept moderate (a few ohms) there will be little influence. The ratio between the cables resistance and the input resistance is very large. Indeed, the contact resistance of the RCA plugs used (terrible connector by the way) is often much larger.
A loop resistance of 1Ohm when feeding a 10kOhm Amplifier input will cause an attenuation of 0.001db.
The Cable inductance also matters little as long as it is kept moderate. The higher the load impedance is, the less relevant the Cable inductance becomes, the lower the load impedance is, the more relevant the cable inductance will become. Interconnect cables of about 1m (3&#39) lengths rarely have an inductance of more than 1uH.
At 20kHz a 1uH inductor will have an impedance of about 0.13 Ohm, causing an additional -0.0001db attenuation.
Even with a 1nF input Capacitance in parallel with the 10kOhm Input Resistance (IEC Load) the attenuation by the Inductance is not significantly larger.
The Cable Capacitance is however crucial for interconnects. I hinted at that when I explained my "first order effects". The Capacitance to cause a -0.1db Roll-off at 20kHz with a 100 Ohm Source Impedance is about 15nF. If our source Impedance is however 1kOhm, a 1.5nF Capacitance will cause this roll-off.
I have seen Output impedance&#39s of around 1kOhm in many pieces of mass produced Hi-Fi equipment. As the UK HiFi-Choice Magazine regularly prints Cable-Reviews that include technical sections with measurements, I can estimate the sort of maximal capacitance a cable may have. A capacitance of a few nF is easily accumulated on longer runs of various shielded cables, not to speak of the "unrolled capacitor" type Cables.
I would conclude that in line-level interconnection the DC-Resistance and Inductance of the cable are of purely academic interest. Constructions with significant resistance or inductance will likely not manipulate the sound of the signal passing through it in any significant way.
A capacitance as low as possible is however desirable. It seems also desirable to have the dielectric (read insulator) in the Cable to be of as good a Quality as possible.
Given my (and many other peoples) experiences with Capacitors, Teflon seems the best solid dielectric, while Air is even better. Polyethylene is also quite acceptable as dielectric while lesser plastics and specifically PVC are out.
Many commercial interconnect cables use PVC insulation.

--------quoted from TNT-Audio [I]The Naked Truth about Interconnect Cables[/I]

aaronyy

最初由 输入法 发表
[B]在高中课本里是无关的,可当你进一步深入学习,你会发现理想的电容不存在,实际电容的等效模型是比较复杂的... [/B]

对呀，既然你的模型这么复杂所以说导线的频率响应更加不肯能是平直的了。

aaronyy

最初由 hyperma 发表
[B]像分布电容、电感这些词汇，都是出现在高频（可不是倒霉的音频信号20千赫哦）放大电路上的，是广播、通信中用的，我无线电学的一般，但是起码知道这些东西不会在简单的音频放大电路上出现，音频放大器，要考虑的是其... [/B]

用在普通设备上，0.001db的失真当然可以不考虑啦。
但是再hi-fi器材上0.001db的失真是能够听出来的呀。
你喜欢普普通通就去听AM收音机好了，反正你也听不出区别吧。

hyperma

0.001分贝的失真你能听出来，我知道，你是蝙蝠的后代。你的耳朵比眼睛更敏锐。

输入法

换线的发烧友让我又羡慕又同情(主要是羡慕),已经在线上花几千上万元了,其他器材也一定是让我辈大流口水,同时,曾经沧海难为水,听过了顶级器材,对于重放中的瑕疵也一定比之我辈更加敏感,更糟糕的是,你已经发烧到几近弹尽粮绝,换线是最便宜的选择,唯今之计,攒钱已经不是办法,只有拼命挣钱,集齐天下名器,不同的音乐类型用不同的器材播放,再不行,只好弄一台时空穿梭机,去听现场,最后永远留在某个伟大的历史瞬间了.
这让我想起了一个很古老的笑话,具体细节记不清了,大概是说某君为一超级发烧友,家中名器无数,各种线材也早已换尽,连电源线也是碗口粗细,从发电厂直接引来,可仍觉不妥,终日郁郁寡欢,一日终于忍耐不住,打电话给发电厂:你们用山西的煤替掉淮南的煤我听听效果.
笑过之后,不觉有一丝凄凉,发烧到这样,我容易吗?!

gene

一群不玩线的人侃线，能侃出个什么结果？？？

上一张数码线（￥10000）的照片。

aaronyy

晕，有AES/EBU接口为什么不用。
实在是暴殓天物啊。

hyperma

没玩过线敢跟你侃？去年我贴的照片你看过么？那一墙的线你记得么？还有那配在Meridian音箱后边的一堆Timber？

嘀咕

最初由 aaronyy 发表
[B]晕，有AES/EBU接口为什么不用。
实在是暴殓天物啊。 [/B]

用了AES/EBU接口还怎么展示这条线！？