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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Hi Dave,<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I built one on perfboard (<a href="https://shedsynth.wordpress.com/vcf/">https://shedsynth.wordpress.com/vcf/</a>) and I like the sound of it, but I have no idea how accurately it compares to Moog.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>That page has some dry audio samples that you might compare with yours, and some links to articles that helped me.<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>I’m bringing it to the </span>Synth DIY weekend in Cambridge <a href="https://www.synth-diy.uk/">https://www.synth-diy.uk/</a> if you’re in UK.<span style='mso-fareast-language:EN-US'><o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Al<o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US>From:</span></b><span lang=EN-US> Synth-diy <synth-diy-bounces@synth-diy.org> <b>On Behalf Of </b>David G Dixon via Synth-diy<br><b>Sent:</b> Saturday, June 10, 2023 5:09 AM<br><b>To:</b> synth-diy@synth-diy.org<br><b>Subject:</b> [sdiy] Yves Usson's Minimoog Filter<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Hello SDIY Team,<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>I've built a ladder filter on my own PCB layout from Yves Usson's Minimoog ladder filter schematic, and I must confess that the results are less than stellar. The filter works, but not terribly well, and it sounds nothing like a Minimoog. I used 2N3904 and 2N3906 instead of BC547 and BC557, but I matched all of the transistor pairs in the ladder, and matched the four transistors at the top and bottom of the ladder as well as the other four transistors, using Ian Fritz's transistor matching circuit (which I also laid out and built on a PCB). I did not try to match the one PNP to the current driving NPN below the bottom of the ladder.<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>Does anyone here have any experience with this schematic? Will it change anything if I replace the 3904s with 547s, etc? Everything else was exactly as specified in the schematic. This was my second attempt to build from an Yves Usson ladder filter schematic. My "Raging Bull" Taurus filter didn't work at all.<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>I just want to know if there is some fundamental flaw in this schematic before I spend too much more time with it. Any insights would be most appreciated.<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>Dave Dixon<o:p></o:p></p></div></div></body></html>