I'm using an STM32F746G for exploring embedded audio DSP. My experiments sound great in headphones but when I connect the audio output to external amplifiers, the signal level is low and there's a lot of whine to don't hear in phones.
I'm using the same output jack (CN10). It's described in the manual both as a "line out" and a "headphone out." Reading about headphone levels it seems like they should be decent for line level although I thought I might need to pad a few dB.
Any tricks or tips to using that as a line out? Unique DAC config? Blocking caps?
Thanks.
Best Answer
I think this just comes down to "no attention given to audio signal path" as there's a lot of apparent crosstalk between the input and output and I have to keep levels artificially low. Btw, no class D. Looked at signal with a scope. I don't think there's a panacea for this; just use another board if you're doing serious audio.