Anonymous
10/30/2025, 1:15:15 AM
No.2954103
>>2954100
>the relevant information is the amplitude of the audio, not the frequency
oh, I see. The SPI at the top of the board will be 0 to 3.3 V, and the audio is -5 to +5 V. I would hope that the loudness of the audio signal is going to swamp any interference I happen to pick up. Having said that, at the inputs of the LM13700s the signal is attenuated to about 30 mV by resistor dividers before being amplified again by the OTA.
I can't say I've ever had interference problems on strip board or bread board, but PCBs are new to me and so is the mixing of analog and digital worlds. Pic related is the prototype. I would have thought that if my signals survive in this mess then surely any kind of PCB has to be better, even if designed by a total noob
>the relevant information is the amplitude of the audio, not the frequency
oh, I see. The SPI at the top of the board will be 0 to 3.3 V, and the audio is -5 to +5 V. I would hope that the loudness of the audio signal is going to swamp any interference I happen to pick up. Having said that, at the inputs of the LM13700s the signal is attenuated to about 30 mV by resistor dividers before being amplified again by the OTA.
I can't say I've ever had interference problems on strip board or bread board, but PCBs are new to me and so is the mixing of analog and digital worlds. Pic related is the prototype. I would have thought that if my signals survive in this mess then surely any kind of PCB has to be better, even if designed by a total noob