VCO on breadboard

I made a clone of M@@G Prodigy VCO on breadboard and got a strange problem.
The sound is a little vibrating. Why? Does breadboard cause the problem?


Some of the immediate dangers of breadboards I can think of:

  • Stray capacitance (in the pF range) between parallel rows. Sometimes, things that work on breadboard do not work on a PCB because this stray capacitance stabilize op-amps.
  • Grounding! All return currents taking the same path. This will cause various sections of the circuit to work at a different ground voltage.

I found the source of the problem: too long wire (20 cm…) between exponential converter and oscillator…

Oh my! The “little vibration” was probably Lorde on some radio station…

That is a pretty funny error. :slight_smile: