# 3340 stripboard - pulse width detuning **URL:** \ **Category:** DIY STUFF\ **Created:** [April 4, 2020, 2:01am UTC](https://lookmumnocomputer.discourse.group/t/3340-stripboard-pulse-width-detuning/520 "2020-04-04T02:01:48Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![fredrik](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/fredrik/32/682_2.png) [@fredrik](https://lookmumnocomputer.discourse.group/u/fredrik)\ **Post date:** [April 4, 2020, 2:36am UTC](https://lookmumnocomputer.discourse.group/t/3340-stripboard-pulse-width-detuning/520/2 "2020-04-04T02:36:53Z")
It’s a known issue with the 3340s, see e.g. this subthread: > [@1222 Tuner VCO Module](https://lookmumnocomputer.discourse.group/t/1222-tuner-vco-module/16/27): > > Oh, as a note, I built my #1112 Oscillator’s with ferrite beads as listed on the diagram, and they seem have enough resistance to cause PWM pitch drift when you change the PWM knob directly or apply a CV to the PWM input. This is a pretty common problem with the CEM3340’s as they are super sensitive to changes in current (on pin 3 if I remember right), but when I built my eurorack VCO Maximus boards, which are also 3340 designs, I used the same ferrites without issue so figured I would be ok. Un… --- _[View the full topic](https://lookmumnocomputer.discourse.group/t/3340-stripboard-pulse-width-detuning/520)._