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发表于 2013-2-3 19:21:15
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原帖由 woodear 于 2013-2-3 18:58 发表 
好像记得FM就是这么吹的？
信口胡说吧。
FM主要设计者说的是：（http://www.fmacoustics.com/pdf/audiophilpoweramp.pdf）
“Impedance, Damping and Load
The lower the output impedance of the amplifier, the less negative influence the Back-EMF can
have on the amplifier's circuit)'. Remember that the output impedance consists of amplifier and
cable/connector! It is impedance of the entire interface that defines the damping of the
diaphragm. In this criteria tube amplifiers fail to deliver accuracy (amplifiers having an output
transformer can never provide optimal damping resulting in a corresponding mushy and ill-
defined bass reproduction).
For a power amplifier the combination of the above-mentioned phenomena results in a very
complex and continuously varying load that is changing dynamically with the frequency and the
level of the music signal! Traditional design theory indicates that an amplifier output current
capability in the region of 5 to 15A is sufficient, but in actual use peak current requirements of
several hundred A are required when driving demanding speakers! It is not unusual to find that
amplifiers that are specified for continuous 2 Ohms operation are failing to drive speakers with a
nominal impedance of 4 Ohms without noticeable compression, signal damping, limiting or
instability effects. At some frequencies some speakers (e.g. electrostatics) however can present a
dynamic impedance roughly comparable to a 0.5 Ohms resistance! From this it becomes quite
clear that most speaker cables are truly a weak link in audiophile systems.”
[ 本帖最后由 Phase 于 2013-2-3 19:23 编辑 ] |
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楼主
发表于 2013-2-3 19:41:31
