Powering Horn Speakers

william chan

Recently I had come across some horn speakers from Panasonic.
I am surprised that they are 330 ohm impedance at 30 watts.

Anybody can recommend a simple amplifier IC that can power these?

Thanks.

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www.fd.com.my
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Mike Green

You are not likely to find a simple amplifier IC that will match well with these. Semiconductor circuits in general tend to work better with low impedance outputs. Your best bet would be to use some kind of output transformer in reverse. Some of those used for PA systems might work. It should be easy to find a 30W transformer with an 8 Ohm winding and one somewhere in the 200 to 500 Ohm range, then you could use pretty much any audio power amp IC to drive it.

jmalaysia

Those are likely PA speakers designed for use with a transformer coupled circuit, usually 70vac here. However, the speaker itself is probably low impedance if you wanted to do some surgery and eliminate the transformer inside.

Beau Schwabe

william chan,

If it's truly a "horn" (<-- something you just want to be loud), and not something that you want to use for a PA, then a dirty square wave or PWM signal to a transistor capable of handling 100V at 300mA should work just fine.· Don't forget a back-emf diode!· Treat the speaker coil (even if it is a piezo) as though you would a motor or relay.

P = V^2 / R

P * R· = V^2

V = SQR(P * R)

V = SQR(30Watts * 330 Ohms) = 99.5V

I = V / R = 99.5V / 330 Ohms = 302mA











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Beau Schwabe

IC Layout Engineer
Parallax, Inc.

Post Edited (Beau Schwabe (Parallax)) : 5/14/2008 4:20:25 AM GMT