Electronic – Audio oscillator cross-talk on small synth project

When switching to a 10X probe I am now seeing a high quality signal. The probe was the issue the entire time.

This issue is resolved.

The reason for the sawtooth shape at the collectors of the transistors is caused by the B-E junction of the transistors and C1 / C2.

You can insert resistors in series with the base of each transistor - I'd start with 10k and see what happens. Be sure that the resistors are in series directly at the base of each transistor. That should give you a much more square-looking waveform at the transistor collectors.

The reason the sawtooth waveform happens is that the E-B junction of the transistors looks like a very-low impedance when the capacitors are charging via the 1k collector resistors. Think of it this way: the capacitors are almost in parallel with the collector E-C leads. There is a 0.6V region when the capacitor is beginning to charge that is high-impedance but as soon as the E-B voltage reaches 0.6V, the impedance drops to a very low value.