This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Friday, August 5, 2016

Korg MS-20 Filter

Switching it up this week and doing a Filter Friday. This one could be used for both synth and guitar/bass. It's a cool filter effect based around the LM13600/13700.

33 comments:

  1. by the way, do you have a schematic for it as a schematic and not a layout :) ?
    I want to make few pcbs of 4 of those on one pcb :)

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    1. Sure thing.

      http://i756.photobucket.com/albums/xx206/storyboards27/Mobile%20Uploads/E9B94169-591E-4021-A7C4-D929F7F7BD6E_zpsdxarmfs2.jpeg

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  2. This looks like a great project! I've built a fair amount of pedals at this point but I've only done one perf build, and it was pretty messy. Can you point me in the direction of a good walkthrough about building on perf? I'm curious about the best way to make the connections on the underside of the board. Should I use wire, or try to bend the leads around, something else I haven't thought of? There are so many great projects on here, think it's about time I did some learnin' about perf. Thanks!

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    1. I don't know of any good walkthroughs. Personally I bend the leads. I start with resistors and diodes, bend all the leads and solder accordingly. Then I populate the caps (smallest to largest), bend any leads and solder. Any connections left I make with cut offs. Good luck!

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  3. Thanks for that, it does help. I still have a few questions though. Do you solder the leads at bends or just where the components go through the board? Would you maybe be willing to post a few pictures of the front and back of one of your builds so I could get a visual idea of how things look?

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    1. I solder them at the holes they come through as well as where leads join together.

      https://postimg.org/image/z32yj2chh/

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    2. Thanks!! Sets some ideas straight in my head.

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  4. isn't there a way to have a cv input?

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  5. i built it but doesnt seems to work properly

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    1. i also built it, used LM13700 and have some heavy noise and feedback, i can only use a 50% of each pot

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  6. In the PCB layout DPDT switch connections are wrong. Check the schematic to correct them and it will work fine.

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    1. Could you be more specific in how to correct the errors? Thanks!

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    2. I could be wrong on this but given the numbering convention SW2 (IC Input) SW5 (IC Output) SW 1/6 (sig input) SW4 (GND) SW3(Vref)

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  7. will this circuit work on 3.3v/ 5v?

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  8. output should be on volume pin 2 no? pin 1 to gnd and 3 to signal?

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  9. I wanted to build a stereo version of this to warm up my digital synths, but I still read the tag "unverified" below this post. Such a pity... Has anyone finished it?

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  10. From reading the schematic; shouldn't lugs 2 and 3 of the volume be the other way around with lug 2 being the output like in most conventional layouts?

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    1. Yes, but it works the same when you reverse those lugs. It's just the lesser used convention (tho DBA uses it all the time).

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  11. I hope someone verifies this one eventually, it sounds cool

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  12. I Think you can now tag it verified, mine seems to work properly, however with a few strange behaviour. When Reson pot is turned fully CW it produces a loud "mic-feedback" sound ; when Freq pot is turned fully CCW it totally cuts the sound.
    I don't know exactly how to use this with my bass :o) but I'm sure I 'll figure out !
    I use a LM13600 and wired the switch exactly like described on the layout.
    I'll try to debug the pots issues adding some resistors in paralell here and there and will come back to tell you more.
    And many thanks for this blog and your great work !

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  13. UPDATE : I didnt' notice with the bass (Std Jazz bass) but with the guitar (humbucker pickups) the sound is distorted.
    Perhaps this filter is not intented to be used with a guitar or a bass ?

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  14. And it is the same with both LM13600 and LM13700...
    Should I add a resistor in series at the input, or increase the value of another one already on the board ? If an expert has the answer...
    I also tried with my mixer headphone output : a lot less distorted at reasonable volume. But the sound is still pretty lo-fi and the pot's strange behaviour increased.
    Well, probably not verified yet. A DIY stompboxes guru should find a way to make it work properly.

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  15. OK, this is my last comment. I promise !
    I added a 47k resistor in series at the input : no more distorted sound !
    I then add a 10k resistor in serie at Reson pot's leg 3 and a 1k in serie at Freq pot's leg 3 : no more loud "mic-feedback" sound when Reson pot si turnde fully CW !
    I guess these pots don't act exactly as they should but it does work that way.
    You can use these values as a starting point to experiment...

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    1. Hey I've had the same problem and couldn't figure it out. The 10k and 1k resistors goes in series with what? Each mentioned pot? Like solder a resistor in lug 1 and 3?

      Sorry for my english and thank you very much for posting!

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