# AS3340 VCO /w hard/soft sync, FM modulation **URL:** \ **Category:** DIY STUFF\ **Created:** [February 13, 2020, 7:01am UTC](https://lookmumnocomputer.discourse.group/t/as3340-vco-w-hard-soft-sync-fm-modulation/249 "2020-02-13T07:01:03Z")\ **Posts on this page:** 1\ **Showing post:** 22
**Author:** ![Dud](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/dud/32/610_2.png) [@Dud](https://lookmumnocomputer.discourse.group/u/Dud)\ **Post date:** [June 15, 2020, 1:34pm UTC](https://lookmumnocomputer.discourse.group/t/as3340-vco-w-hard-soft-sync-fm-modulation/249/22 "2020-06-15T13:34:32Z")
for the bypass cap on the power supply you have some info here > [@Typical module power circuit](https://lookmumnocomputer.discourse.group/t/typical-module-power-circuit/1134/3): > > Different schools: 10 ohm and capacitor near power header (this basically results in an RC low pass filter, but with a voltage drop over the resistor depending on the current). Usually somewhat pointless (the resistors, not necessarily the capacitors). 10 ohm without capacitors (either using them as fuses, expecting them to die if something’s shorted, or possibly just cargo culting, trying to do the above but forgetting how things work, see “power sins” [here](https://northcoastsynthesis.com/news/design-mistakes-in-synth-schematics/) for more). Ferrite beads (if done … > [@Trumac22](#): > > it’s up and running but the pitch wobble on the PWM is pretty severe. > [@Trumac22](#): > > 3340 osc doesn’t wobble on PWM much PWM it’s with an external signal in PWM input, and the PWM pot ajust the level of signal in to zero to max , there should be no problem with that, I think you are talking about the PW pot for PW pot you can add a trimmer pot on the pot for adjust what you want (to pin 1 or 3 or both of the pot) but did i understand well your problem? --- _[View the full topic](https://lookmumnocomputer.discourse.group/t/as3340-vco-w-hard-soft-sync-fm-modulation/249)._