That takes me back.. that looks very similar to something I built out of an article in an electronics magazine article in ~1987.
I do remember it had remarkably good sound quality from such a simple circuit - it basically sounded like "professional" broadcast talk radio. Lots of fun spying on siblings etc.
I was building and selling these things about 18 years ago. My favorite part about it was I could scavenge all required components from a broken cassette deck. Made a nice income for a school boy, upgraded my computer from i486 to Pentium II.
That takes me back.. that looks very similar to something I built out of an article in an electronics magazine article in ~1987.
I do remember it had remarkably good sound quality from such a simple circuit - it basically sounded like "professional" broadcast talk radio. Lots of fun spying on siblings etc.