DrFrankencopter
Well-known member
[quote author="radiance"]Thanks Peter. Yeah, spend all afternoon reading about 800+ search results on the word "servo" LOL. Still don't REALLY grasp how it's actually working :evil: :evil: :evil:
What I did learn is that most people here seem to dislike the sound of DC servo circuits and that the listening test in this post prove that a good quality cap is a safer bet.
I think I'll have to learn a programme like spice to really get these things...[/quote]
A servo circuit is essentially an integrator. Feed the integrator circuit with your (nominally AC) audio input, connect it's output to the inverting input of the 'audio path' op-amp, and now the integrator attempts to cancel out sustained low frequencies. Voila, any DC present on the input will be nulled out. You have to pay some attention to the component values...you need to pad the output of the servo down, but not too low, or it won't null enough DC. Choose a servo IC with a low DC offset.
Cheers
Kris
What I did learn is that most people here seem to dislike the sound of DC servo circuits and that the listening test in this post prove that a good quality cap is a safer bet.
I think I'll have to learn a programme like spice to really get these things...[/quote]
A servo circuit is essentially an integrator. Feed the integrator circuit with your (nominally AC) audio input, connect it's output to the inverting input of the 'audio path' op-amp, and now the integrator attempts to cancel out sustained low frequencies. Voila, any DC present on the input will be nulled out. You have to pay some attention to the component values...you need to pad the output of the servo down, but not too low, or it won't null enough DC. Choose a servo IC with a low DC offset.
Cheers
Kris
