ATTiny is generating PWM based tones with 32kHz sampling rate. Then I've created R-2R DAC and then trying to amplify it for the speaker.
I need to make low pass RC filter, to cut PWM hiss during playback and some white noise during silence. I have tried to make use of bypass pin but no difference.
So where should I place RC filter and what values in order to filter out PWM hiss and noise during silence?
Update(without scope, I've tried to describe the problem as much as I can):
This is captured on DAC output using sound card, to describe the signal.
actual .wav file of the capture download: https://www.dropbox.com/s/pwakovmu9h695ji/beep1.wav
Since my sound card is not able to capture the white noise I hear from speaker, I've tried to record voice using my phone.
Sec 22 I turn off speaker pin. Sec 31 turn on again.