Here is a stereo FM transmitter design, based around the BA1404 integrated circuit.
If you want to get rid of those pesky audio wires leading from your computer to your amplifier here is a simple circuit that will enable you to do just that. Simply atach the audio-out cables to the circuit and tune your FM tuner until sound starts playing on your speakers.
This stereo transmitter circuit is based around the BA1404 fully integrated FM transmitter. Only a few discrete components are required to get it going. You can find the schematic, as well as a comprehensive guide on how to build your own, at the Electronics-DIY blog.
Via Electronics-DIY.
Here’s a better one: http://www.km5z.us/FM-Stereo-Broadcaster.php
It’s also a far more complicated solution and depending on your needs wholly unnecessary. It is a cool project too though.
Yeah, it would be more complicated. I’m wondering how the above performs in audio quality. Of course, just a quick view; I’m thinking the tuning isn’t stable.
BA1404 chips are old chips with crappy performance. They were pretty cool in 1988, but there are better alternatives these days. Even with a crystal, they’re very prone to drift. Electronics-DIY claims they have a great new circuit design, but I seriously doubt they’ve been able to overcome the limitations of the chip itself. I used to sell these BA1404s over at radiochips.com (thanks for ripping off my copy, Electronics-DIY!), but once I ran out, I didn’t bother stocking any more.
The ST chip definitely looks better and they have one that take in digital audio and does RDBS.