[sdiy] Help! LM566 alternate?

[Mike]

Just going from memory...
I think the VCO built into the NE567 tone-decoder PLL chip (also an 8-pin
DIP) is similar to the NE566 VCO internally. A triangular waveform would be
present on the timing capacitor but would need to be buffered with an op amp
for driving  external circuits.

But if you wanted to try that, perhaps better using a CD4046 for a simple
VCO instead and enjoy much wider range using small film capacitors, no need
for electrolytics.
Just a thought.
Mike