10 May
2009
10 May
'09
11:46 p.m.
On Sat, May 09, 2009 at 09:33:40AM -0700, Justin Smith wrote:
Someone please correct me if I am wrong, but I am
under the impression
that running a PA with no speakers is in no way harmful. It is similar
to having an electric outlet without anything plugged into it, your
real danger is too heavy a current drain (ie. sticking a fork in the
electric socket, or a low impedance speaker in a speaker jack that
cannot handle that low and impedance).
As a previous respondent pointed out, this is basically correct except
when the final drive of the amplifier includes a transformer.
But check with the designer, e.g. the specifications provided by the
manufacturer. They take precedence over public opinion. ;-}
A well designed semiconductor amplifier will take into account the
possibility of either shorts or open circuit.
The design can detect either insufficient current or excessive current,
and take corrective action. With a typical eight ohm speaker load this
isn't that difficult.
Take pity on radiofrequency amplifiers used in radio transmitters, where
the load depends on the frequency being used, and a typical antenna
looks like a dead short unless it is being driven at close to the right
frequency.
--
James Cameron mailto:quozl@us.netrek.org http://quozl.netrek.org/