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Old August 16th 03, 01:04 AM
Floyd Davidson
 
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"Ralph Mowery" wrote:
proper voltage? When you connect speakers to an amplifier, do you
worry about what the source impedance is, so long as it's low enough
to not materially affect damping? If not, why would you worry about


I would not go there on the audio . The speakers do need to match the design
of the amp just as the load on a transmitter needs to match the design
impedance. Most power output devices are designed to produce maximum power
and /or minimum distortion into a specific load.


Virtually all "HiFi" audio amplifiers are designed to have
"damping" factor of something significantly more than 10.
Damping factor is the ratio of the load impedance to the
amplifier's output impedance. You might even find a few (more
expensive units) that have ratios greater than 1000, which is to
say that the output impedance of the amp (designed to drive
speakers in the range of 4 to 16 Ohms), has an output impedance
of 4/1000 of an Ohm).

Just as with RF, the output impedance has little to do with the
power delivered to the load impedance. The amplifier can
generate a maximum voltage by design, and how much power is
actually delivered depends solely on the impedance of the load.
Hence the same amplifier can deliver twice the power to a 4 Ohm
speaker as it can to an 8 Ohm speaker, and that is twice what it
will deliver to a 16 Ohm speaker. And it also works just fine to
drive a 600 Ohm headset, with significantly less power.

--
Floyd L. Davidson http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)