[Collins] Advanced Optics 312B3 and 4 ohm spkr questions

[Dr. Gerald N. Johnson, electrical engineer]

In general you can put a higher impedance load on an output. You don't
really want to put a 4 ohm speaker on a 16 ohm amplifier output. It
makes the output stage work into something approaching a short and runs
the currents up. The slightly saving grace is that speaker impedances
are anything but constant, they depend on the environment, especially
the controller and the frequency. When I've slipped the impedance a
little low on some PA amplifiers, I've had to go back and change all the
speaker impedances because the current limiter in the solid state power
supply shut the amplifier down just when the preacher got warmed up good
and began invoking hell's fire and brimstone...

73, Jerry, K0CQ, Technical Advisor to the CRA.
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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.