Euphoria High Pitched Primary Oscillator
Hello, I am about to finish the Euphoria Synth. Most of the pcbs are working fine, except the envelope PCB for which I have a missing CD4001. I am also missing the tertiary oscillator pcb. Xan those be bought separately?
However, my problem concerns the Primary oscillator, which is very high pitched even at the lowest primary oscillator frequency level. I tried changing the C34 to a lower value, which indeed allows me to set a lower frequency, but then the slider has only a limited action. And as I read from the CEM3340 datasheet usually that capacitor is fixed to 1.5nF, so I guess this is only a bad solution. There is probably a wrong value somewhere, but rather than desoldering everything, maybe there could be a hint at which components to check first, or a hint on some voltage's I could measure on some pins. Most IC's seem to work fine when I probe them.
Thanks a lot, I look forward to testing this nice synth!
Hey Franchesco,
please contact the shop where you purchased the PCBs. There should not be a board missing.
Regarding the high-pitched tone, the cause is likely somewhere around the 3340 frequency section. Relevant parts include C34, R24, R23, C13, RT8, and RT9. The pitch CV input, pitch knobs, and FM inputs can also affect the frequency. I would start by checking those areas closely.
If you need the schematics, just let me know.
Thanks, Stefan