Posted inanalog2.0

Improvement of Analog2.0 LFO

The schematic above represents the latest Analog2.0 LFO circuit. This circuit has a long-existing problem. The oscillation affects the power supply and that causes instability in VCO pitch; You would hear the VCO pitch shifting along with the LFO’s oscillation. I’ve tried eliminating this problem.

Posted inanalog2.0 tech notes

Noise Source Transistor — Conclusion

I have been working for a while to determine which transistor to use for noise source in noise generator.  I was using 2SC3311 which was obsoleted recently. I did several tests, mainly by listening, and chose BC547.  The reasons are: It has good taste as a noise source.  Easy to find sweet spots when using it with a filter and VCA. Noise level was close to 2SC3311, so my previous design works with simple replacement. Availability is good. Unlikely to get obsoleted soon. I started the test with listening "raw" noise without any modification and filtering.  However, it didn't work well.  Many of the candidates sounds similarly.  However, I found…