Korg 35 Clone MS20 HP & LP VCF (1 of 2 MS20 filters) - DIY Modular in a Week 7.3 HD

One of the most DIY made Voltage Controlled Filters must be the MS20 filter. But did you know there are two different kinds of filters that was put in the MS20, depending on how old it is. In this episode I go through the first MS20 filter, which was built around the mystical Korg35 chip. Changes to the original schematics accoriding to the following should/could be done: - For +/-12V R17 should be changed to 17K (instead of 22k), and R6 to 240K (instead of 300K) - Change C4 to a 10uF instead of a 10nF for better stability If an electrolytic cap is used then the negative lead should be towards the opamp. - More resonance could be accomplished by exchanging R16 with just a lead (skip the R16) and change the 100k Trimpot to a 500k. This trimpot should be set depending on transistor used. - HP input: Connect a 2k2 and an input jack between C3 and R18 to get HP functionality. HP and LP "should" not be used at the same time... Day 7: Filters Part 3: Korg35 HP/LP Voltage Controlled Filter (Early MS20 filter) Difficulty: Intermediate Price: ~9$ MiaW playlist: https://www.youtube.com/playlist?list=PLyE56WXw0_5Q5QGMEXWmskuhojKyRdA3T Visit my Patreon page for more (different) content, or if you just want to support my work more than just a thumbs up :) https://www.patreon.com/SourceryOne Link to the schematics: http://www.synthdiy.com/show/?id=2176 Link to Jürgen Haibles schematics: http://jhaible.com/legacy/jh_720_vcf.gif Link to the frontpanel design: https://www.dropbox.com/s/isudwmjx6m57yuk/7.3%20Korg35_inspired_vcf_7HP.svg?dl=0 Link to oscilloscope: https://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&toolid=11800&pub=5575103922&campid=5338181421&mpre=https%3A%2F%2Fwww.ebay.com%2Fsch%2Fi.html%3F_from%3DR40%26_trksid%3Dm570.l1313%26_nkw%3DDSO138%26_sacat%3D0 Tim Stinchcombes extensive write up on the MS10 and MS20 filters: http://www.timstinchcombe.co.uk/index.php?pge=korg