[sdiy] Square to Sine

[Magnus Danielson]

The backside of that would be that the 2 pole gives only 12 dB/oct 
compared to the 3 pole giving 18 dB/oct, thus giving less suppression of 
the square overtones. Their roll off would be 18 dB/Oct vs 24 dB/Oct 
from the filters. You would have to add a passive RC-link to achieve the 
same performance.

The simplicity of the RC link setup is good starting point from a 
learning perspective.

Cheers,
Magnus

On 04/05/2017 04:41 AM, Andrew Simper wrote:
> One way to avoid some of the volume drop is to use a 2 pole sallen key
> BJT filter with a cascaded passive stage. This is a common circuit
> used around BBD chips, eg:
>
> http://www.hobby-hour.com/electronics/s/schematics/boss-ce2-chorus-schematic.gif
>
> Andy
>
> On 4 April 2017 at 19:50, Elaine Klopke <functionofform at gmail.com> wrote:
>> Thanks for the info Tom!
>>
>> Magnus, the sources are fixed square waves coming from a set of PIC chips. So the fixed filtering doesn't bother me a bit. One filter for one frequency. What worries me is the volume drop.
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy