I have builded a basic example of a radio with RDA5807M using the attached example (with minor changes using L2C OLED, using true buttons), working well - and i have builded a Spectrum analyser working well with PC, mobil phone.
On radio, im using a dektop PC speaker with mini jack connector. Also spectrum analyser have a jack conenctor.
After comes a big idea - connect both together using mini jack splitter - but after comes my problem:
i hear on speaker weird low frequency noise, what visualised on spectrum analyser too, i have removed after a sec, because sounds not good.
Why working both standalone well and together not? How can i connect both together without problem? What i have forget? or hardware limitation?
On the schematics not visible, but where the speaker visible on radio i have added a jack connector, so is possible plug with mini jack splitter a ,,second audio device".
On spectrum analyser schematic, the jack connector is a left side connected on mini jack L R and GND.
Im not sure, this radio build can use more than one audio device. However i can use this splitter almost by all device.
How are you connecting them together? On the output of the radio board before the class D amp board?
We need to see the full circuit in the problem configuration. I wonder if there's a ground loop.
Definitely don't split the class D output, that's never going to work. Split between the radio and the amp. Class D signals are digital, not analog, and are not ground-referenced (they are differential).
