I cannot get the second BJT amplification of Experiment 11 of Charles Platt's Make: Electronics to work, and I'm all out of clues. This question is very similar, but not identical as my circuit works fine up to the first amplification. This question is also about experiment 11, but does not seem related.
The first 2N2222 is fed the output of the 2N6027, which discharges the 0.0047uF cap with a frequency in the kHz range; this amplifies this signal. If I hook up a speaker between the first 2N2222's emitter and ground, I hear a buzzing sound, just as the book says.
Now, if I attempt to amplify this buzzing with the second 2N2222 as shown in the circuit, the speaker just cackles a bit. Initially I thought I might have overloaded the speaker, but no matter how much I experiment with the various resistors, I don't here any buzzing.
I guess this is something that can easily be analyzed with an oscilloscope, but unfortunately I don't have access to one yet.