internal amplification

hi there.

I was going to try to build the schematic featured in this old Popular mechanics article.

http://www.swtpc.com/mholley/PopularElectronics/Nov1967/PE_Nov1967.htm

I was wondering though.. What if I just want to put a little speaker on it? like maybe PC speaker size.

What would be the best way to amplify it enough to make it as loud as say a PC Speaker can be?

thanks.

How about using an actual computer speaker? I'm sure it would be no problem to find someone who has an old set laying around that they'd give you for free.

The "master" speaker already has the amp built in . All you would need to do is break open the case (no big loss) and mount the speaker and amp in your theremin case. You could even mount the "slave" speaker in the theremin as well to provide sound on the player's side and on the audience side.

i happen to have an old set of computer speakers but they are 110V.

I am hoping for something unpowered or that I can power off maybe the same 9V in that powers the theremin. I guess ideally the speaker would go when the audio out was unplugged and turn off when the patch cord plugged in.

I am just getting back into electronics on this project after being trained in it 12 years ago then promptly getting into software right after.

I miss it though and am eager to refresh.

Hmmm....that's odd. The majority of standard two speaker sets that I've seen (are 110V in the US) use an AC/DC adapter which drops the voltage down to 9-12 volts. My high powered satelite/subwoofer set does have its own internal power supply.
If for some reason your speakers have their own internal power supply, you might be able to bypass it and use a low voltage power supply instead.
If I'm not mistaken, all you need to do to cut off the audio when an instrument cord is inserted is to use a switching jack.

Or, if would be loud enough to be a pitch preview, you might want to just install a switch that would disconnect the internal speaker.

my computer speakers probably do have a internal power supply that i can bypass. the power supply is down in the subwoofer anyway.

Maybe i can find another cheap pair somewhere.. I probably shouldn't bother taking apart these ones with the sub woofer.

When I first mentioned a PC speaker i was more thinking of the internal PC speaker that is usually mounted inside a computer case and connected directly to the motherboard.