Don't try and compare line level situations with speaker load situations, as there is more to take into account in the case of speakers.
In the line level situation, which you asked about initially, the connection is made using voltage bridging (AKA impedence bridging). Maximum power transfer is not required, and this configuration is more resistant to noise. In the case of a power amp to speaker connection, you need to be able to a number of things. You need to be able to generate a serious amount of power to move the speakers, and you need to be able to control these mechanical devices, particularly around the area of their mechanical resonance. For these reasons, speakers have a relatively low impedance, to enable good power delivery, but the power amp will, as opaquiece states, typically have an output impedance of around 0.1 ohms. While the lower output impedance does not optimise the power transfer, it does increase the damping factor. The higher the damping factor, the better controlled the speaker will be. Thus there is a trade off between power delivery and control. Also, you misunderstand the labelling of the output terminals on the MacIntosh. When they say 2, 4, or 8 ohm output load impedence, they are talking about the nominal impedance of the speakers, and not the the output impedance of the amplifier itself. -- bigfool1956 David Ayers Music is what counts, hifi just helps us enjoy it more ------------------------------------------------------------------------ bigfool1956's Profile: http://forums.slimdevices.com/member.php?userid=13782 View this thread: http://forums.slimdevices.com/showthread.php?t=46347 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
