[sdiy] Making a HPF using a LPF...??

[Jean-Pierre Desrochers]

Yes I meant VCF as a Low Pass Filter

JP


----- Original Message ----- 
From: <houshu at muj.biglobe.ne.jp>
To: <jpdesroc at oricom.ca>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, April 10, 2012 7:31 PM
Subject: Re: [sdiy] Making a HPF using a LPF...??


> Hi JP,
> 
> What do you mean by LPF?  If your LPF is a VCF, there is an example:
> 
>  http://www5b.biglobe.ne.jp/~houshu/synth/moritaVCF76.gif
> 
> Trim pot is needed to get good response.
> 
> Adding HP input is another method:
> 
>  http://www5b.biglobe.ne.jp/~houshu/synth/Vcfv0212.GIF
> 
>  http://houshu.at.webry.info/201010/article_2.html
> 
> In most cases, they are not "pure" HPFs, 
> but not-pure HPF in MS20 is sufficiently useful.
> 
> Sam HOSHUYAMA
> Saitama, JAPAN
> 
> ----------
> From: "Jean-Pierre Desrochers" <jpdesroc at oricom.ca>
> Date: 2012/4/10 23:24:06
> HI list,
> Maybe it's a dumb question but
> I need to make some light on the following..
> Can I make a High pass filter using a Low pass filter
> and a summing amp using both positive and negative inputs?
> Suppose the following:
> A wave form passes thru a LPF, then we mix
> the LPF output filtered wave (negative input)
> with the LPF input unfiltered wave to the mixing amp
> positive input.
> Will the summing amp output be a HPF from
> the incoming wave ?
> 
> JP
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy