Is this an amplifier that could take a speaker level input?

All a speaker-level output is is a giant version of a line-level output . With an appropriate transformer, you can pad that speaker level output back down to something reasonable for a simple opamp like you've linked to, but the transformer required to do that would likely my much more expensive than the amplifier itself. Simply using a ton of resistance won't be great, as you can easily overload the first amplifier's outputs. As for the output of this amplifier itself, taking a look at the schematic we can see that the resistor in parallel with the output is 10ohms. That will change depending on frequency because we also have a capacitor in the same 'branch', but in general we can say that 10ohms is close enough to "speakerland" that this circuit could be used to drive a speaker with no problems, even if the designers did not tell us so.

Getting past that hurdle, take a look at the opamp's datasheet - scroll down the the 'electrical characteristics' section. The maximum output power is going to be limited by the voltage supply rails (simple physics; you can't output more power from a circuit than you're supplying to it). When the supply is a relatively reasonable 9v, peak output power is limited to about 1/3 of a watt. It'll make sound, but probably not as much as you'd like unless you're using an incredibly efficient speaker. How loud does this need to be?

http://www.datasheetcatalog.org/data...io/de05001.pdf

Quote:

Originally Posted by custommadename;13106200
This is awesome stuff! How much more can be known once I get the bullhorn taken apart? It's not here right now, but probably tomorrow I'll have it in pieces.

Click to expand...

Well, a model number and such would be a great start. Really anything you can use to identify it, perhaps even the model of the compression driver itself.

Sorry custommadename, i originally misread your original question thinking you wanted a headphone jack. I also did not know you where driveing a bullhorn.

I just facepalmed myself. I will be graduating with a degree in Electronic Engineering in May. I knew everything that Chipp was talking about, i just did not think the problem through all the way.

The item you picked out on ebay could easily drive a headphone speaker, but nothing bigger than that.

Even though a compression driver would be better for your application than a standard audio power amplifier, i think a audio amplifier would be cheaper and easier to find. Compression drivers are a bit of a specialty item.

Here are some ideas:

http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&pa=127255&productId=127255&keyCode=WSF&CID=GMC 7 Watts $17

http://www.amazon.com/Sure-TPA3123-Class-D-Audio-Amplifier/dp/B003XRMBJK]Amazon.com: Sure 2x8W @ 4 Ohm TPA3123 Class-D Audio Amplifier Board: Electronics[/URL] 8 Watts $15

http://www.sparkfun.com/products/9612 38 Watts, $30

These require a external power supply, but you could easily modify them to connect to a computer power supply. (or any other power supply for that matter)

Hope i was helpful.