[sdiy] removing dc offset

[gregory zifcak]

yeah,
i'm pretty sure this is what's happening. in order to generate an opposite 
offset i'd have to add a negative supply, right? i was hoping for a simpler 
fix. i guess maybe i'll just high pass filter the thump out and live without 
the bass for now.
thanks for all the suggestions,
greg


>I got the impression that this is not your case... it seems like the thump 
>is
>there
>everytime you make the sound. This can be really hard to get rid of unless 
>you
>know
>exactly when the sound will occur.
>
>This can happen with some cheap circuits where the power is OFF whenever a
>sound is not being produced...then the unit 'one shots' when triggered. So 
>the
>voltage might go from zero to 1/2 the supply with an AC wave riding 
>it...and
>back to zero.
>
>If you can predict when the sound starts, you can generate an opposite DC 
>offset
>
>(dynamic) that will largely cancel the one from your circuit.
>
>It will NOT be a simple toy anymore...
>
>I had a similar problem with my guitar synth design. When there are no 
>strings
>playing, the waveforms do not go to zero, but to the peak value. This make 
>a
>huge thump in the VCF. Because I know when this will happen, I force the 
>waves
>to
>zero (they are still at the peak but I am clamping them to ground).  You 
>could
>do similar...
>
>H^) harry
>
>gregory zifcak wrote:
>
> > how would this work? can you explain it a little more?
> > thanks,
> > greg
> >
> > >
> > >Ah, so you are worried about the thump, i.e. the sudden step in dc 
>voltage,
> > >not the dc itself.
> > >
> > >Perhaps a relay in series with the output would help, which is turned 
>on
> > >delayed?
> > >
> > >Ingo
> > >
>