Please help a Noob with a low pass filter

halogravity · Joined: Jul 23, 2016 Posts: 3 Location: USA

Hello, my name is Chris and I'm quite new to electronics and circuit bending. I have been taking a psuedo-modular route, and creating circuits that I can add to my bends to make them more robust. I have a cool PT2399 delay circuit working, and my next step is a filter. I have been having a hell of a time finding a low-pass filter that sounds good, has a relatively low parts count, and is fairly easy to build. A problem I am having is I am new to schematics, so they are quite baffling to me. I have tried tutorials and the like, I just cant seem to get it working. I am currently attempting to breadboard a filter by Pete McBennett, https://www.youtube.com/watch?v=yZSkNASlMjM. The schematic is here: https://drive.google.com/file/d/0Bzxodk3UiKRgSXc0OVBWQnNfM00/view. Pete himself is quite busy and hard to get a hold of, so my question, on bended knee, pleading for help is, can someone show me what this looks like on a breadboard? A fritzing image would suffice. I am not trying to get someone to do the work for me, I am just having a hell of a time making it work myself, and if I can see what its SUPPOSED to look like I can figure out what I'm doing wrong. Even just the filter part, as I don't really need the oscillators anyway. Any help anyone can give me would be massive here, I have been making myself crazy for weeks. My sincerest thanks for any guidance anyone can provide, and my apologies for the long winded post.

blue hell · Posted: Mon Aug 08, 2016 1:01 pm Post subject:

Well .. on a narrow screen it would be long winded, but on a wide screen it could be broad minded Laughing

Anyway ... that looks like a lot of components used for a filter ... especially when not so experienced with building stuff that may not be the best idea.

How about http://electro-music.com/wiki/pmwiki.php?n=Schematics.KorgLateMS20Filter - there are more filters in the Wiki, just search for VCF

O .. and welcome

halogravity · Joined: Jul 23, 2016 Posts: 3 Location: USA

Hello! Thank you for the link, but it seems like these are mainly schematics, Im having a hard time translating schematics to breadboard... the filter I posted didnt seem very complex, and it sounds fantastic... Im mainly looking for a breadboard of it (or similar) so I can compare that to a schematic and facilitate learning to read schematics. If that makes sense... but thankyou for the info!

blue hell · Posted: Mon Aug 08, 2016 2:20 pm Post subject:

Ah ok, yes that makes sense :-)

I never liked stripboard .. heh . .so am not of much use there, but maybe a seeing a PCB design along with the schematics can offer some insight.

For instance : http://electro-music.com/wiki/pmwiki.php?n=Schematics.PolivoxVCFLayout

halogravity · Joined: Jul 23, 2016 Posts: 3 Location: USA

Thats what Im looking into right now. I'll figure this out yet! haha.

Jayteefos · Joined: Oct 07, 2016 Posts: 1 Location: Massachusetts

If you're doing this just for the sake of learning how to read a schematic, by all means, continue. My best advice is to look at the nodes in the schematic, count how many components should connect to each node and double check that against your breadboard.

If you just want a simple filter project with a minimum of fuss, I suggest you find Shane Williams in the circuit benders group on Dacebook, and ask if he has any more of his filter PCBs left. It's a nice simple implementation of the Steiner Parker filter, runs on 9V, and can be made in an afternoon.