RE: [sdiy] Butterworth design

[rdrake]

use a 4.7k + a 1k trimmer?

>----- ------- Original Message ------- -----
>From: czvekan at gmail.com
>To: Synth-diy at dropmix.xs4all.nl
>Sent: Tue, 17 Jun 2008 15:24:40
>
>Hi group,
>
>I am gonna have to design a Butterworth 2nd Order
>Low Pass Filter for  
>the Audio Output after a 24-bit Burr&Brown DAC
>PCM1753.
>Now my little software for filter design from Texas
>Instrument is is  
>suggesting a 5.23K resistor. If my cutoff frequency
>is supposed to be  
>24.1 kHz -60dB. Of course I don't have that value
>handy.
>My question is if I'd use a 5K6 1% resistor it
>filters something like  
>22.5 kHz almost 2k off .
>Is that very critical to the sound & distortion? Or
>are these just   
>standard values /recommendation that have somewhat
>of a toleranc.
>I mean the frequency is not even audible up in that
>range. Or am I  
>loosing valuable high end frequencies with it.But
>still, I understand  
>it causes some digital noise from the ∆∑-DAC
>that needs filtering.	
>Does it have to be exact the frequency 24.1kHz?
>
>Csaba
>
>
>
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