Portable Stereo Amp

[Rawrcasm]

It's been a countless number of times that I've needed a little amp to drive some speakers from a weak source, and now that I'm full of free time and a closet full of salvaged parts, I think I'm ready.

Example uses would be connecting my phone/iPod to a pair of 8Ω speakers, or connecting my TV to both those 8Ω speakers + some ceiling speakers that are of unknown impedance.

My plan is to pretty much have a headphone jack input, and both a left and right output, powered by batteries, perhaps with three pots for Volume, Treble, and Bass.

Some parts I have within my reach that I think may be relevant are:
**broken link removed** - Quad Ground Sense Op-Amp
**broken link removed** - Dual Ultra Low-Noise Wideband Op-Amp
**broken link removed** Pre-Amp Transistor
.. and parts from printers, scanners, drives, vacuums, and an old Home Entertainment Stereo system.

Any help would be appreciated.

 

[MikeMl]

I can go to my local University's Surplus store, and buy a set of used PC speakers for $5. These are set up for stereo; some have a center sub-woofer. They typically come with 9-12VDC Wall Wart, but they will run just fine in a car. I have used them to augment the crappy audio from a portable DVD player.

I have seen these at neighborhood garage sales for $1.

 

[BrownOut]

I doubt you would need or want controls for volume, treble and bass, since the source generally has those controls. (Don't know about IPOD, as I don't want one) I'd suggest you keep it simple, and just provide the power gain and leave those details to the source. You can find many power amp schematics on the internet. Some are very simple like this one, and you should make yours as simple as possible. There are better circuits, and I'll try to find some when I get back home. Also, if you build one of these, pay attention to heat in the output stages. You'll need to use appropriate heat sinks. And, as in any power circuit, don't apply full power supplies when you power it up for the first time. Either turn up your voltage slowly while observing the current draw, or use current limited power supplies.

 

[Rawrcasm]

Well, thanks for the responses.