{"id":4243,"date":"2024-01-22T15:02:42","date_gmt":"2024-01-22T15:02:42","guid":{"rendered":"https:\/\/maffez.com\/?page_id=4243"},"modified":"2024-11-20T06:58:27","modified_gmt":"2024-11-20T06:58:27","slug":"poley-2140-based-pole-mixing-vcf","status":"publish","type":"page","link":"https:\/\/maffez.com\/?page_id=4243","title":{"rendered":"POLEY:  2140 based pole-mixing VCF"},"content":{"rendered":"<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"2183\" height=\"1861\" src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1799.jpeg\" alt=\"\" class=\"wp-image-4545\" style=\"width:372px;height:auto\" srcset=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1799.jpeg 2183w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1799-300x256.jpeg 300w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1799-1024x873.jpeg 1024w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1799-768x655.jpeg 768w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1799-1536x1309.jpeg 1536w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1799-2048x1746.jpeg 2048w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/figure>\n<\/div>\n\n\n<p>Some plucky sound with one Poley<\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/Poley_LP4.mp3\"><\/audio><\/figure>\n\n\n\n<p>Here are two Poley Filters in parallel but oneruns with inverted signal polarity &#8211; why? Vowel sounds!!! <\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/11\/PoleyClips_x2.mp3\"><\/audio><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What&#8217;s POLEY?<\/strong><\/h2>\n\n\n\n<p>This is a pole mixing filter based on the SSI2140 filter IC (remake of SSM2040). What&#8217;s different here is that you have pole mixing for different filter responses (bandpass, highpass,  etc.), and compensation for level loss on higher resonance settings.  The PCB is fitted for an expansion panel not yet designed) that gives you reso CV and more filter types. <\/p>\n\n\n\n<p>Some audio demo from breadboard version:<\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/01\/2140BPreS_Polemix_Test1.mp3\"><\/audio><\/figure>\n\n\n\n<p>What I wanted, apart from different filter responses, was to utilize the internal resonance VCA of the 2140 for a trick I learned from SSI&#8217;s awesome paper AN701, namely that level loss on resonance can be avoided when using bandpass resonance. So, this is, strictly speaking, not passband level loss compensation by pumping more level in proportion to increased resonance, but actually bypasses the broader phase cancellations going hand in hand with classic LP feedback. <\/p>\n\n\n\n<p> I implemented this trick in different filzers already, yet the challenge with the SSI2140 is that the resonance VCA input, unlike on the CEM3320, is prewired\u2026 now, if you can mix filter poles for different responses, you sure can mix filter feedback bandpass &#8211; yup! Only thing is that this requires you to attenuate the filter input a little bit more as things get more voluminious in contrast to passband level loss style resonance.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"985\" height=\"1024\" src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1788-985x1024.jpeg\" alt=\"\" class=\"wp-image-4448\" style=\"width:401px;height:auto\" srcset=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1788-985x1024.jpeg 985w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1788-289x300.jpeg 289w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1788-768x798.jpeg 768w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1788-1478x1536.jpeg 1478w, https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/IMG_1788.jpeg 1949w\" sizes=\"auto, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/figure>\n<\/div>\n\n\n<h2 class=\"wp-block-heading\"><strong>Proto Testing<\/strong><\/h2>\n\n\n\n<p>Just got three nice proto boards from aisler, and whoop! Here&#8217;s more audio blooops<\/p>\n\n\n\n<p>Stock modes: 4lp, 2bp, 1lp, 2hp<\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/1feb_poley_pcbproto_done.mp3\"><\/audio><\/figure>\n\n\n\n<p>And the same with audio rate modulation<\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/1feb_poley_pcbproto_modulationtest.mp3\"><\/audio><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Modifications<\/strong><\/h2>\n\n\n\n<p>At the moment I&#8217;m simply toying around, but might out some of these in an expander module that also offers reso CV and more filter responses.   <\/p>\n\n\n\n<p><strong>Resonance diode limiting<\/strong>: Although you can tweak the maximum amount of resonance by means of R22, diode limiting the feedback path is also nice. Use D3 and R45 (not present on PCB)  as per schematic. R45 is at 75k at my module. The lower the value of R45, the stronger the limiting effect.<\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/diodelimit_reso.mp3\"><\/audio><\/figure>\n\n\n\n<p><strong>4P out normalled to MOD input<\/strong>: Simply wire the 4pole out to the normal pin lug of the MOD in socket via a 100k resistor. If no cable is plugged into the MOD input, you can use the bipolar mod amount knob for dialling in self-FM-ing madness. Listen to some responses with that mod:  <\/p>\n\n\n\n<figure class=\"wp-block-audio\"><audio controls src=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/4ptofmmod.mp3\"><\/audio><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Schematic<\/strong><\/h2>\n\n\n\n<div data-wp-interactive=\"core\/file\" class=\"wp-block-file\"><object data-wp-bind--hidden=\"!state.hasPdfPreview\" hidden class=\"wp-block-file__embed\" data=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/Poley_2140-1.pdf\" type=\"application\/pdf\" style=\"width:100%;height:600px\" aria-label=\"Embed of Poley_2140-1.\"><\/object><a id=\"wp-block-file--media-9e7401fc-73a6-4ef2-a74b-56d62be6d3f8\" href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/Poley_2140-1.pdf\">Poley_2140-1<\/a><a href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/Poley_2140-1.pdf\" class=\"wp-block-file__button wp-element-button\" download aria-describedby=\"wp-block-file--media-9e7401fc-73a6-4ef2-a74b-56d62be6d3f8\">Download<\/a><\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Gerber Files<\/strong><\/h2>\n\n\n\n<div class=\"wp-block-file\"><a id=\"wp-block-file--media-2d866925-c0af-461c-82dd-9a77c14efb41\" href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/Poley_PCB.zip\">Poley_PCB<\/a><a href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/Poley_PCB.zip\" class=\"wp-block-file__button wp-element-button\" download aria-describedby=\"wp-block-file--media-2d866925-c0af-461c-82dd-9a77c14efb41\">Download<\/a><\/div>\n\n\n\n<div class=\"wp-block-file\"><a id=\"wp-block-file--media-9e148cd4-51d3-420e-8756-1dac0945733b\" href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/POLEY_PNL.zip\">POLEY_PNL<\/a><a href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/02\/POLEY_PNL.zip\" class=\"wp-block-file__button wp-element-button\" download aria-describedby=\"wp-block-file--media-9e148cd4-51d3-420e-8756-1dac0945733b\">Download<\/a><\/div>\n\n\n\n<p><\/p>\n\n\n\n<div data-wp-interactive=\"core\/file\" class=\"wp-block-file\"><object data-wp-bind--hidden=\"!state.hasPdfPreview\" hidden class=\"wp-block-file__embed\" data=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/03\/Poley_2140_BOM.pdf\" type=\"application\/pdf\" style=\"width:100%;height:600px\" aria-label=\"Embed of Poley_2140_BOM.\"><\/object><a id=\"wp-block-file--media-fa2aaba7-1e15-4bfe-ba04-a4a48555eb1e\" href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/03\/Poley_2140_BOM.pdf\">Poley_2140_BOM<\/a><a href=\"https:\/\/maffez.com\/wp-content\/uploads\/2024\/03\/Poley_2140_BOM.pdf\" class=\"wp-block-file__button wp-element-button\" download aria-describedby=\"wp-block-file--media-fa2aaba7-1e15-4bfe-ba04-a4a48555eb1e\">Download<\/a><\/div>\n\n\n\n<p>btw for integrator caps, oanasonic ECHUX 1N 16 are awesome: <a href=\"https:\/\/www.reichelt.at\/at\/de\/smd-folienkondensator-1-nf-16-v-125-c-2--echux-1n-16-p228782.html?GROUPID=5523&amp;&amp;r=1\">https:\/\/www.reichelt.at\/at\/de\/smd-folienkondensator-1-nf-16-v-125-c-2&#8211;echux-1n-16-p228782.html?GROUPID=5523&amp;&amp;r=1<\/a> <\/p>\n","protected":false},"excerpt":{"rendered":"<p>Some plucky sound with one Poley Here are two Poley Filters in parallel but oneruns with inverted signal polarity &#8211; why? Vowel sounds!!! What&#8217;s POLEY? This is a pole mixing filter based on the SSI2140 filter IC (remake of SSM2040). What&#8217;s different here is that you have pole mixing for different filter responses (bandpass, highpass, &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/maffez.com\/?page_id=4243\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;POLEY:  2140 based pole-mixing VCF&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-4243","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/maffez.com\/index.php?rest_route=\/wp\/v2\/pages\/4243","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/maffez.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/maffez.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/maffez.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/maffez.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4243"}],"version-history":[{"count":3,"href":"https:\/\/maffez.com\/index.php?rest_route=\/wp\/v2\/pages\/4243\/revisions"}],"predecessor-version":[{"id":4899,"href":"https:\/\/maffez.com\/index.php?rest_route=\/wp\/v2\/pages\/4243\/revisions\/4899"}],"wp:attachment":[{"href":"https:\/\/maffez.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4243"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}