Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels #ubitx #ubitx-help


Latest update: I have solved the clicking issue when operating the VFO. The cause is that the Si5351 chip is very sensitive to noise on its VDD inputs. The design of the decoupling seems to be insufficient because the 3,3V is taken from the Arduino Nano regulator via a fairly long supply trace on the PCB and there is only a 0,1uF capacitor on the VDD inputs.

Solution: I soldered in a 1000uF electrolytic cap over the VDD input on the Si5351. Problem solved.... See attached schematic and pic.
My uBitx version is V4.

Join to automatically receive all group messages.