Ms-20 filter with dual ota

softfin · Posted: Sun Sep 23, 2007 3:24 am Post subject: Ms-20 filter with dual ota

Due to the new forum rules I decided to delete the schematic. I'm sorry.

creekree · Posted: Sun Sep 23, 2007 1:00 pm Post subject:

neat, thanks for that!

shawn · Joined: Dec 13, 2005 Posts: 209 Location: savannah

Man, thank you for sharing this!

bubblechamber · Posted: Mon Sep 24, 2007 5:24 pm Post subject:

nice job. I just breadboarded it and work straight away. I need to do some fine tuning. thanks for putting this up. I'll try and get a pcb done this week and post it.
[/i]

softfin · Posted: Thu Sep 27, 2007 5:20 am Post subject:

bubblechamber · Posted: Thu Sep 27, 2007 12:56 pm Post subject:

I have looked at Scott's site on how to connect 2 and I'll be using that as a guide, sort of. I'm doing some experiments in adding CV to the Rez, I'm using an old EFM design + the original layout, I'm cautiously optimistic. and I'm thinking about adding a 4069 based distortion option, like Fonik did on his new Wasp filter, sort of. And I'm going to try and add bandpass to it as well.
Hopefully I'll have something to show next week, or at least some audio clips. I really like the way this filter sounds...

bubblechamber · Posted: Thu Oct 18, 2007 5:56 pm Post subject:

sorry, I got a little distracted with something else...I'm etching the first board tonight and hopefully I'll have some samples and pics tomorrow. the breadboard version sounds great. if this goes well, I should have a PCB finished and posted next week.

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

That's great bubblechamber, i like to try the PCB!!!
Thank you.

endif · Joined: Jul 14, 2006 Posts: 138 Location: Reno, NV

If it goes well, perhaps that can be the prototype for a run of PCBs?
=]

Peake · Posted: Sat Oct 20, 2007 1:34 am Post subject:

Here is a reduction of the Korg 35 IC, if anyone's interested. I don't know if it'd work or how it'd sound, if anyone is interested in going the long route... Cheers on making PCBs!

http://picasaweb.google.com/lh/viewPhoto?uname=RMCsynthesisers&aid=5005548513980958289&iid=5005556605699346578

ericcoleridge · Joined: Jan 16, 2007 Posts: 889 Location: NYC

I've seen alot of schems of the web for the later Korg35 filter, but not so much for the other.
I thought this was strange because I would presume that the discrete filter would be easier to clone.

edit:
I'm not sure anymore which MS20 VCF version was early, and which was late, but this Rene Schmitz layout is for the 'discrete' non-korg35 MS20 VCF and is here:
http://www.analog-synth.de/synths/mod2/ms20filter/rene_ms20_filter_clone%20rev%204.pdf

I've made a couple of these, and played them side by side with an MS20-- they're pretty much exactly the same--really great.

Peake · Posted: Sat Oct 20, 2007 8:57 pm Post subject:

I have no idea which one is better-sounding/more desirable. That's partly why I'm throwing this into the mix, as I hope to learn from just such discussion.

I've had a few MS20s over the years (when things were cheap), but I couldn't tell you which had what, as I've never side-by-sided the versions. I have with the MKS80 versions, however. That post is in the AH archives.

I -have- heard some of the "clones" and filters based, even generally upon the MS, and only the Analogue Solutions Vostok had some dirt and overload. The others sound rather clean and open, which disappointed me. MS20 users all find the sweet spot of having both filters highly resonant and very close together in Fc. They puff and blur very nicely this way. That's what I want. Sorry if this is resulting in a thread hijack. I should just find these things myself and keep quiet Wink

I want to know! More importantly, I want to build these cool circuits, and thank those who are making them up.

bubblechamber · Posted: Sat Oct 20, 2007 9:38 pm Post subject:

well, here's what my first board sounds like. there was a bit of trouble shooting and hopefully more progress tomorrow. this sample is Low Pass only, sweeping up and down. Resonance comes in about half way.

MS20_LP.mp3

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proto1.jpg

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rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

humm...sorry, dumb question here

what is this?:

some cmos gate?(i'm not kidding i don't know Embarassed

)

blue hell · Posted: Mon Jan 26, 2009 6:28 pm Post subject:

frijitz · Posted: Mon Jan 26, 2009 6:31 pm Post subject:

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

aah
i've never seen it drawn like that

thanks,
i'll try to build it tomorrow

StephenGiles · Joined: Apr 17, 2006 Posts: 507 Location: England

It's often drawn like that I think.

rubendelacosta · Joined: Dec 25, 2005 Posts: 153 Location: lisbon

am i missing something or a two ways switch would do the job here?
like this:

thanks,
ruben

habibelhabab · Joined: Mar 04, 2010 Posts: 7 Location: belgium

ik think the result in high pass mode is better if you inject the input signal into ungrounded C3. (like suggested elsewhere)