electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » Lunettas - circuits inspired by Stanley Lunetta
Simple Low pass resonant filter for your lunetta
Post new topic   Reply to topic Moderators: mosc
Page 1 of 1 [4 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
efabric



Joined: Jan 05, 2012
Posts: 19
Location: Caen, France

PostPosted: Mon Mar 26, 2012 7:30 am    Post subject: Simple Low pass resonant filter for your lunetta Reply with quote  Mark this post and the followings unread

Hello,

I found a long time ago this schematic on the squarewaveparade website :
http://thesquarewaveparade.com/images/srlpf.jpg

It's a 1 opamp low pass filter.

I'm not sure, but I think therr's a little mistake in the In and Out jacks ground. Don't the input and output must be decoupled with capacitors ?
The virtual ground in the power supply (4,5v) is directly linked to the ground output and input.

I think it's false no ?
Thank you.

_________________
My Scoopit DIY Synths and Schematics curation

Last edited by efabric on Tue Mar 27, 2012 12:33 am; edited 1 time in total
Back to top
View user's profile Send private message
Psyingo



Joined: Jun 11, 2009
Posts: 248
Location: Canada

PostPosted: Mon Mar 26, 2012 9:17 am    Post subject: Reply with quote  Mark this post and the followings unread

Yep, that's a classic sallen-key filter. Replace the dual gang pot with two vatrols for simple voltage control. That's my favorite filter topology.
Back to top
View user's profile Send private message
richardc64



Joined: Jun 01, 2006
Posts: 679
Location: NYC
Audio files: 26

PostPosted: Mon Mar 26, 2012 10:30 am    Post subject: Re: Simple Low pass resonant filter for your lunetta Reply with quote  Mark this post and the followings unread

efabric wrote:
The virtual ground in the power supply (4,5v) is diretly linked to the ground output and input.

It's fine, as long as the 9V that powers it isn't used to also power something that expects -9V to be ground -- in other words, single-supply.

_________________
Revenge is a dish best served with a fork... to the eye
Back to top
View user's profile Send private message Visit poster's website
efabric



Joined: Jan 05, 2012
Posts: 19
Location: Caen, France

PostPosted: Tue Mar 27, 2012 1:05 am    Post subject: Reply with quote  Mark this post and the followings unread

It's a little bit strange...

I'm planning to build my modular lunetta with various units : 5v CMOS and ?V opamp based analog circuits.

What is the good way for everything to work together ?

I have a nice working radial transformer regulated 10V power supply in my bench, and 5V regulators in my spare parts.

Do you thik I can use this 0V, +10V and +5V to power up my opamps ?
Can I use the same +5V to power the CMOS modules and the virtual ground of the opamps ? Is there a risk of parasitic digital noise in the analog path ?

Can you show me a diagram with the interconnections and the decoupling stages ?

_________________
My Scoopit DIY Synths and Schematics curation
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: mosc
Page 1 of 1 [4 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Lunettas - circuits inspired by Stanley Lunetta
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use