review33.com:影音天地:前級的控制力?

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[#1] 前級的控制力? 請問可用那个技術指標可知道前級控制力的強弱? Thanks		re33view 正式會員 14.xxx.xxx.220	2012-04-20 21:58

[#2] 前級的控制力?
價錢 !

mastercook

正式會員
218.xxx.xxx.180

2012-04-23 13:36

[#3] 前級的控制力?
Good answer since I cannot find another spec told it.

RDT

正式會員
14.xxx.xxx.4

2012-04-23 21:17

[#4] 前級的控制力?
最近磅的指標應是輸出阻抗，越低越好。增益高亦會給人一個錯覺是推力強。

thomasc2

正式會員
14.xxx.xxx.144

2012-04-23 21:32

[#5] 前級的控制力?
相信前置的輸出工率(output power)會有關鍵性影響o 可惜spec 係冇嘅!

Derek2A3

正式會員
116.xxx.xxx.250

2012-04-23 22:34

[#6] 前級的控制力?
最簡單的不如以前級的輸出電壓做參考 , 能輸出高電壓的前級大多數有相當的控制力 . 但控制力好的前級不代表聲音一定是最好的 , 所以看指標做參考還是不如親身聆聽的準確 .

mastercook

正式會員
219.xxx.xxx.109

2012-04-23 23:08

[#7] 前級的控制力?
"""前置的輸出工率(output power)會有關鍵性影響o 可惜spec 係冇嘅"""

"""能輸出高電壓的前級大多數有相當的控制力""""

恕難認同。

眾所周知，幾乎所有後級都是設計在少於2V輸入就已經有滿度輸出，前級超過2V的輸出電壓祇會clip左部後級。

一枝12AX7 1V輸入就可以放大到80V輸出，五極管更閒閒地有過百倍放大，但是成百K的輸出阻抗，推玩具車都唔會夠力。

最後修改時間: 2012-04-24 00:24:23

thomasc2

正式會員
14.xxx.xxx.144

2012-04-24 00:22

[#8] 前級的控制力?
輸出阻抗與控制力的關系隋便做個"輸出阻抗"的yahoo search 就有很多文章講到，如http://modernmusician.com/forum/showthread.php?t=73165 其中一句 :

""".........當輸出阻抗Zout變大時，分壓的結果會使得輸入電壓趨近於0。......"""

唔好靠估，萬一有興趣就搵一兩篇讀下。

最後修改時間: 2012-04-24 00:47:03

thomasc2

正式會員
14.xxx.xxx.144

2012-04-24 00:44

[#9] 前級的控制力?
from original question :
那个技術指標可知道前級控制力的強弱?

this equation seems to point out a few desirable parameters :
Vin = Vout x Zin/(Zin+Zout)
would like output Z low
input Z high
equation simplified to:
Vin = Vout
this made it simple to see if a pre can drive a power to full output, it seems to answer the original question of :
那个技術指標可知道前級控制力的強弱?
it does not say anything about the quality.

kitahara0011

正式會員
97.xxx.xxx.8

2012-04-24 03:52

[#10] 前級的控制力?
C-Hings

For pre-amplifier, i think it is not often to mention "控制力", and it is properly not the best indicator of quality.

If the question is " What are the attributes to distinguish a good pre-amplifer from a bad one?" . Sorry to say most pre-amplifiers exhibit very similar and "great" technical specifications, this is at least for the case of solid state gears.

The following tips are not criteria to distinguish a good line pre-amplifiers from a bad one. These facts could be mentioned already in other threads. They could serve as the "BASIC 101" stuffs for sharing:

1) Impedence matching - you may Google Search for "10-to-1 rule for impedence matching". For electronics, the rule of thumb that the impedence of the input device should be at least 10 times the impedence of the output device to reduce losses. For HIFI, typically the ratio is much much more than 10.

2) Gain - some pre-amp (likely the hi end gears) allows you to configure the internal gain to an optimal level. In many cases, the gain is fixed. Typically, the line pre-amp gain (for CD source) should be around 6 to 15db(and power amplifier ~26 to 32db).Some models/designs may deviate from the mentioned range. This may not indicate a problem, but probably need to be more careful with matching the other gears.

3) If you merit stable 3-D sound stages and precise positioning of instrument images, balanced design with XLR interconnects should have advantages over un-balanced designs.

Nice day ahead!!

最後修改時間: 2012-04-24 08:06:46

faimiu

正式會員
192.xxx.xxx.193

2012-04-24 07:52

[#11] 前級的控制力?
如果真的要從前級規格上窺探得出那部前級的控制力的話 , 我會選擇從那部前級的電流消耗上作估計 . 簡單而言 , 一部對後級控制力好的前級首要條件是自身能作穩定性高的放大性能 . 這有如一個大口水瓶以三十度向下傾倒流水一樣 , 反之水流倒不出來的又有何控制力可言呢 ? 另外當前級的電流輸出 ( 以原子粒前級作比喻 ) 推動不起後級時反而成為後級的負載的話就更談不上控制力的了 .

這樣正如有人用平價CD 機直入後級一樣 , 聲音很呆滯 , 音場散亂等 , 這都是因為前級成了後級的負載而造成 , 一部對後級有良好控制力的前級不只在技術規格上就可以道盡一切的 .

mastercook

正式會員
219.xxx.xxx.163

2012-04-24 18:23

[#12] 前級的控制力?
近年用家都係用dac直入後级，忽略了前级的音色貢獻。

aheung

會員
219.xxx.xxx.14

2017-10-12 08:42

[#13] 前級的控制力?
溫古而知新！！

phil.ng

會員
14.xxx.xxx.134

2017-10-12 08:46

[#14] 前級的控制力?
中