[sdiy] Ladder filters using different different filter topologies.

Ben Riggs benalog1977 at gmail.com
Sun Feb 10 11:02:47 CET 2019


Thanks for that, I had not come across these before. One of my first attempts looks similar to the the A1377, I’m glad here were some sound samples as well.

FYI, it was one of your notes on your website that directed me to try use a ladder for a Sallen-Key VCF ;)

Thanks again,
Ben.

> On 9 Feb 2019, at 8:16 pm, houshu at muj.biglobe.ne.jp wrote:
> 
> Hello Ben and List,
> 
> Alisa 1377 and 1387 have Sallen-Key ladder filters.
> 
> http://www.ruskeys.net/eng/base/alisa1377.php
> http://www.ruskeys.net/eng/base/alisa1387.php
> 
> I wrote blog articles on them. Although they are in Japanese, they may help you.
> 
> https://houshu.at.webry.info/200704/article_1.html
> https://houshu.at.webry.info/201101/article_3.html
> 
> Osamu HOSHUYAMA
> Saitama, JAPAN.
> 
> 
>> 2019/02/08  18:20  Ben Riggs <benalog1977 at gmail.com> wrote: 
>> 
>> Great reference but that’s not it.
>> 
>> Basically, I’m trying to nut out a Sallen-key filter using diodes as current controlled resistors in a ladder/differential topology to remove the CV-bleed… but I can’t help but think I’ve seen it before.
>> 
>> Ben. 
>> 
>>> On 8 Feb 2019, at 4:01 pm, Lloyd Abbott < lloydabbott94 at gmail.com> wrote:
>>> 
>>> My guess is that you're thinking of Tim Stinchcombe's paper, "Analysis of the Moog Transistor Ladder and Derivative Filters," where he compares transistor and diode ladder filters.
>>> 
>>> Link:
>>> http://www.timstinchcombe.co.uk/synth/Moog_ladder_tf.pdf 
>>> 
>>> On Fri, Feb 8, 2019 at 8:27 AM Ben Riggs < benalog1977 at gmail.com> wrote: 
>>>> Hi SDIY Peeps, 
>>>> 
>>>> The last week I’ve been musing about filter designs, and (by default) to solve the CV bleed through I keep thinking ladder design. Then I keep remembering a document that I can’t reference that had different filter topologies based about the ladder design. 
>>>> 
>>>> Can anyone help finding the document? 
>>>> 
>>>> Cheers, 
>>>> Ben. 
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> 
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