{"id":3023,"date":"2019-04-18T19:55:23","date_gmt":"2019-04-18T19:55:23","guid":{"rendered":"http:\/\/millionmachinemarch.com\/?p=3023"},"modified":"2022-05-21T18:12:12","modified_gmt":"2022-05-21T18:12:12","slug":"quad-octoginta-ii","status":"publish","type":"post","link":"https:\/\/millionmachinemarch.com\/index.php\/2019\/04\/18\/quad-octoginta-ii\/","title":{"rendered":"Quad Octoginta II"},"content":{"rendered":"\n
\"\"<\/a><\/figure>\n\n\n\n

Since the CEM3340 chip was put back into production, and after seeing what a few other makers have built with them, I decided it was time for me to come up with my own take on this ‘tried and true’ chip! I looked over the various designs on using the CEM3340’s and settled on the Octoginta II<\/a>. <\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

Now that the VCO’s were sorted and I was able to purchase the DIY PCB’s, I needed to choose a wavefolder design. I like what Yusynth did with Haible’s wavefolder and went with his design here:<\/p>\n\n\n\n

http:\/\/yusynth.net\/Modular\/EN\/WAVEFOLDER\/index.html<\/a><\/p>\n\n\n\n

The YuSynth design required me to make my own PCB’s. This can be a laborious process if you have not done it before. But I have the process down to a science here in the lab, so I was able to get these made pretty quickly. Taste the Sodium Persulfate in the air, aahhhhh!<\/p>\n\n\n

<\/p>\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

First I downloaded the PCB mask template from the website and scaled it to size. Then I burn a screen and print the mask onto the bare copper clad board. Then etch the copper off in a tank of Sodium Persulfate, rinse and let dry. Then drilled the holes and fixed whatever needs to be fixed.<\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

Next step was to design the layout of this massive 72HP beast. It took a couple of redesigns before I could get it down to ONLY 72HP wide \ud83d\ude00 Here I output four CEM3340 chips into four YuSynth Wavefolders and out to a four pole joystick. Lots of sonic real estate! This will also be my second go at creating a synth voice, my first was taking 3 WMD Spectrums and creating the TRISPECTRUM. You can find that first creation here:<\/p>\n\n\n\n

\n
Complete custom voice for eurorack<\/a><\/blockquote>