electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
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
V/Hz state variable filter
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [12 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
nicolas3141



Joined: May 25, 2007
Posts: 144
Location: Christchurch, New Zealand

PostPosted: Tue May 19, 2009 4:06 am    Post subject: V/Hz state variable filter Reply with quote  Mark this post and the followings unread

Here is a filter to match the VCO http://electro-music.com/forum/topic-32689.html and ribbon controller http://electro-music.com/forum/topic-32651.html

This circuit is pretty much the standard state variable design from the LM13600 datasheet, but with a Q pot and diode clippers added that allows it to oscillate reliably so that it can be used a sine VCO as well as a filter. It has bandpass and lowpass outs.

A fairly basic circuit that sounds okay and is simple enough to understand and be built in a couple of hours on stripboard. It runs off +/-9V (ie two batteries). It expects a CV in the 0-6V range. The output is about a volt or so which won't blow anything up if you run it directly into effects pedals, etc.

It is V/Hz which means that if you set it up to give you C at 1V, you should get C an octave higher at about 2V and an octave higher again at about 4V.

I built mine last year, but have only finished tidying up the drawing, so if you notice anything amiss, please let me know.

Cheers,
Nicolas


filter.JPG
 Description:
 Filesize:  204.98 KB
 Viewed:  2386 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

filter.JPG


Back to top
View user's profile Send private message
drapdap



Joined: Oct 11, 2004
Posts: 194
Location: bp
Audio files: 1

PostPosted: Tue May 19, 2009 4:46 am    Post subject: Reply with quote  Mark this post and the followings unread

Thank You for sharing this Nicolas, these circuits are really nice work.
I haven't got round to building any of them yet, but this filter was the last straw, im gathering parts now...

i'm not shure i understand the +6v switch on the input tho. Is it just to boost the signal so the resonance behaves well?

Does it tolerate +/- 12 volts, or do i need to raise some resistors?
(Of course i'll try it, but a firsthand answer really won't hurt my ego.)

is there more of these? Smile

thank you a gain

róbert
Back to top
View user's profile Send private message
nicolas3141



Joined: May 25, 2007
Posts: 144
Location: Christchurch, New Zealand

PostPosted: Tue May 19, 2009 3:07 pm    Post subject: Reply with quote  Mark this post and the followings unread

That switch to +6V is my crude way of showing a switched socket that sees +6V when nothing is attached. It doesn't really need to be +6V, any stable +ve voltage would be fine.

To run it on higher voltage up to +/-15V should be fine, but increase the value of R4, R15 and R17 proportionally (say 6k, 14k and 14k or similar).

Cheers,
Nicolas
Back to top
View user's profile Send private message
loss1234



Joined: Jul 24, 2007
Posts: 1535
Location: nyc
Audio files: 41

PostPosted: Sun May 31, 2009 7:14 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks so much for these great circuits!!!
_________________
-------------------------------------------- check out various dan music at: http://www.myspace.com/lossnyc
http://www.myspace.com/snazelle
http://www.soundclick.com/lossnyc.htm http://www.indie911.com/dan-snazelle
Back to top
View user's profile Send private message
Dego



Joined: Apr 22, 2008
Posts: 139
Location: Sweden

PostPosted: Thu Jun 11, 2009 12:26 pm    Post subject: Reply with quote  Mark this post and the followings unread

Built the filter today. But ran in to some problems.

The q pot does not work properly Sad
It just work a little bit of the pots axel. I use a 100k pot just like in the schematics but should it be 10k?

What could else be wrong?
Back to top
View user's profile Send private message
nicolas3141



Joined: May 25, 2007
Posts: 144
Location: Christchurch, New Zealand

PostPosted: Thu Jun 11, 2009 2:14 pm    Post subject: Reply with quote  Mark this post and the followings unread

I am not quite sure what you mean. When I turn the Q pot to 100% my filter rings (oscillates if there is no input). If I back it off a bit to around 70-90% the filter has that resonant wah type sound. Then as I turn it down further it loses the resonance and becomes more like a tone control type filter. Between 0-70% the changes in the sound of the filter are not very dramatic.

Perhaps a log pot would be better here so that we could get better control over the high resonance end and waste less rotation on the low resonance end.

This general type of filter is quite common, but what distinguishes one from the next is the feedback arrangement to provide Q control. So I encourage you to experiment with different pots and types of feedback. Let us know what you find that works.

Cheers,
Nicolas
Back to top
View user's profile Send private message
Dego



Joined: Apr 22, 2008
Posts: 139
Location: Sweden

PostPosted: Sun Jun 14, 2009 1:57 pm    Post subject: Reply with quote  Mark this post and the followings unread

It works now. I have the same result when I turn the Q pot now. I think that was what puzzled me was that there was not much action until you get to 70% turned Q pot. After 90 it goes crazy... Smile

I will try later on with a log pot....

So that is number 4 of your designs Very Happy
ADSR
LFO
VC-LFO
FILTER

Now I look forward to the Sample & Hold and VCA. Is there a ringmodulation as well? Wink

Thanks for your educational and fun designs!
Back to top
View user's profile Send private message
ogg



Joined: Sep 30, 2009
Posts: 10
Location: UK

PostPosted: Thu Oct 01, 2009 5:23 pm    Post subject: Filter simulation online Reply with quote  Mark this post and the followings unread

Hello, I've put an interactive simulation of this filter online at Music circuit simulations. It seems to be working but not entirely, I'm not sure which input is which and I don't think I have the op-amp voltages right. Thought you might like to see it, please send me corrections if you can see any mistakes.

I've credited you, nicolas3141, and linked to this discussion.

Cheers,

Ollie
Back to top
View user's profile Send private message
v-un-v
Janitor
Janitor


Joined: May 16, 2005
Posts: 8934
Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1

PostPosted: Fri Oct 02, 2009 8:25 am    Post subject: Reply with quote  Mark this post and the followings unread

Hey Ollie! welcome to electro-music.com! Very Happy

I'm afraid this isn't working here (Safari on a MacIntel running OSX). Says it can't read a text file- although I'm getting a screen. A black screen I should add Smile

_________________
ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN.
Back to top
View user's profile Send private message Send e-mail
Blue Hell
Site Admin


Joined: Apr 03, 2004
Posts: 20730
Location: The Netherlands, Enschede
Audio files: 158
G2 patch files: 318

PostPosted: Fri Oct 02, 2009 8:47 am    Post subject: Reply with quote  Mark this post and the followings unread

v-un-v wrote:
I'm afraid this isn't working here (Safari on a MacIntel running OSX).


Hmm .. but it does here ... you have an old Java version?

_________________
Jan
Back to top
View user's profile Send private message Visit poster's website
ogg



Joined: Sep 30, 2009
Posts: 10
Location: UK

PostPosted: Fri Oct 02, 2009 9:50 am    Post subject: Reply with quote  Mark this post and the followings unread

v-un-v wrote:
Hey Ollie! welcome to electro-music.com! Very Happy

I'm afraid this isn't working here (Safari on a MacIntel running OSX). Says it can't read a text file- although I'm getting a screen. A black screen I should add Smile


Thank you Smile

Occasionally I find the applet doesn't start properly and shows a black screen, usually when I click or right-click on it before it's finished setting up. So you might like to try refreshing, or as Blue Hell suggests you could check you have the latest version of Java, the OS X software update should show you if you don't.
Back to top
View user's profile Send private message
nicolas3141



Joined: May 25, 2007
Posts: 144
Location: Christchurch, New Zealand

PostPosted: Mon Apr 12, 2010 3:02 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Dego

one more uploaded. Sorry for the delay, but it has been summer down here and I have not been indoors so much Smile

http://electro-music.com/forum/topic-41277.html

Cheers,
Nicolas
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [12 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
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
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


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