Many people have asked for feedback as an option and compared the PFM2 to Yamaha synths like the TX81z. While this is a completely different instrument I thought it might be interesting to add waveforms from the TX81z and varying feedback levels for each waveform. This took a very long time to get right. Considering the TX waveforms are 4096 samples and the PFM2 has a max 1024 samples they aren't 1:1 but sound basically the same.
The feedback levels only start getting interesting at higher levels. Looking at the waveforms in an oscilloscope I noticed feedback acts a little like a wavefolder + distortion. The highest feedback level without distortion is level 5. I've included 3 versions of the waveforms. One set without feedback, another set at level 5 feedback, and a final set at level 7 feedback.
Each waveform was recorded in Reaper at 48k 24bit around 46.87hz or F#1 tuned sharp. One cycle at that frequency gives you exactly 1024 samples. I had to fix one of the waveforms at feedback level 7 because it was incredibly unstable and would not stay in tune. Very analog like!
All waveforms are included in the zip file with images that show each waveform.
Enjoy!