[Alinco] Combining speakers

[KA4WDK]

Bob said;
 >> I remember 45 years ago in the news department of the radio station,
 >> taking the output of Motorola monitor receivers and combining the
 >> audio for use on a single speaker, but I can't remember just how it
 >> was done.

Then Eric said;
 >Most radio power amplifiers are
 >pretty forgiving, but if they're not you may have to go to a 
transformer-coupled
 >summing bridge that presents a speaker load to each input.  Just be aware 
that
 >some audio power amps get unstable when the load is not within a narrow- and
 >resistive- range.

Be very, very careful  45 years ago, radio audio output amplifiers were 
very forgiving, and easy to tell if you were overloading them before they 
broke.

Today they are unforgiving!  Until it stops outputting, you may not know 
that it is overloaded and/or mis-matched.  Sometimes the speaker acts as a 
part of the dc circuit to the driver IC.

In those past days you could replace a tube for just a few dollars, and 
maybe have to replace a resistor.  Today, you have surface mount components 
and Integrated circuits. Do you have the solder gear to replace an IC?  And 
if you do, can you find the IC?  (In many cases a custom IC is created for 
a radio model, and not a lot of spares are made, and there is almost no 
cross replacement.)

Speakers are cheap compared to the ICs and replacement hassle.  You would 
be better off to find a way to build more speakers into the console.  Maybe 
something innovative like using a single grill on the front but have the 
several  speakers mounted so the all "Feed" the single grill.



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Arthur J. Byrnes
Disclaimer; These views are those only of the author, Arthur.

Be sure to visit my Web Site.  http://www.ajb.com
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