Here is a great site for audio electronics fundamentals and projects. It's Hi-Fi orientated but has great articles on fundamentals and his projects are well explained and are a great learning experience even if you don't build any of his circuits. Take your time looking around as there are lots of different sections and topics covered and can take quite awhile to see it all.http://sound.westhost.com/index.htmlLefty
Not all have been built and verified, but with those that have not this is not an issue, since they cannot help but work.
in my diagram.. all pins 'are' labled.... can you not see them? everything is labeled.. (except a missing 'to GND' lable)