On 25 Feb 2007 01:09:01 -0800, wrote:

I was not aware that domestic audio equipment could have "almost zero"
impedance.
Can you explain further please. What kind of output device is this?


Impedance is 'directional'. That is the impedance that an amplifier
(or whatever...) drives does not necessarly equal the back impedance
of the amplifer.

Say a signal goes to teh speaker. For whatever reasons, some of that
signal is reflected back towards the amplifier. The ideal goal is that
the amplifier appear as a very low impedance to that signal, to help
prevent its being reflected a second time back to teh speakers...

Same basic concept as batteries--an ideal battery has an internal
impedance (resistance, since it is DC) of zero or almost zero. Were
the battery's resistance be any significant value at all, then its
current supplyling capabilities would be rather limited.