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 » YuSynth
yusynth Fixed Filter Bank
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 2 [34 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: 1, 2 Next
Author Message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Wed Aug 15, 2007 7:07 am    Post subject: yusynth Fixed Filter Bank Reply with quote  Mark this post and the followings unread

Hi all

I have added a new module to my yusynth project,
it's a fixed filter bank. You will find the building information at :
http://yusynth.net/Modular/index.html
or the direct link:
http://yusynth.net/Modular/EN/BANK/index.html

It's not a beginner's project though, it uses a large number of parts.
Due to this large number there may be some mislabelled parts in the list of components. Should you find a mistake please let me know it.

Enjoy it

N.B. Don't ask... I don't provide PCBs or kits

--
Yves Usson
http://yusynth.net

_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
frijitz



Joined: May 04, 2007
Posts: 1710
Location: NM USA
Audio files: 54

PostPosted: Wed Aug 15, 2007 7:57 am    Post subject: Re: yusynth Fixed Filter Bank Reply with quote  Mark this post and the followings unread

yusson wrote:
I have added a new module to my yusynth project,
it's a fixed filter bank.

Great job Exclamation

I built a monster bank of 36 filters way back when, so I appreciate what you have gone through to do this. I used a simple single transistor circuit. I think you were very smart to use a higher order design. On mine all the response tails add up to a fairly strong signal, so I have to go to a dangerously high Q in order to get a useful peak-to-valley ratio.

Bernie did a filter bank for ElectroNotes, and he also settled on the Deliyannis topology.

Maybe you could put up some example sound clips -- everyone needs to know how important a module like this is. Very Happy

Ian
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Wed Aug 15, 2007 8:08 am    Post subject: Reply with quote  Mark this post and the followings unread

Well, yes I plan to put some sound samples soon. In particular to illustrate the pseudo stereo effect. Otherwise, I have a Synthesizers.com Q107 FFB and it sounds very similar to mine.
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
Sebo



Joined: Apr 27, 2007
Posts: 534
Location: Argentina

PostPosted: Wed Aug 15, 2007 10:31 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves:
Thank you very much for share your work.
I already built the Minimoog VCF at your site, and sounds great (I own
a Moogerfooger Filter and both sounds really close).
I will start to build a modular synth (soon, I hope) and I think I will build
most of your modules, I have some questions, but I'm saving them for
the time of start building (may be I could answer some myself by that
time).
Thanks again.

_________________
Sebo
---------------------------------------
My Music:
www.cosaquitosenglobo.com.ar
www.myspace.com/cosaquitosenglobo
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Wed Aug 15, 2007 10:59 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Sebo

Don't hesitate to ask if you are experiencing problems while building yusynth modules.

By the way, if you're happy with your minimoog VCF may be you can send me some pictures of the finished module, I'll be glad to add them to the module gallery on my web site.

Cheers

_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
Sebo



Joined: Apr 27, 2007
Posts: 534
Location: Argentina

PostPosted: Wed Aug 15, 2007 11:27 am    Post subject: Reply with quote  Mark this post and the followings unread

Yves:
I actually build 2, one for a friend that uses it as standalone filter for
processing drumloops and synthlines (I added an envelope follower
to it, similar to the Moogerfooger), and another for me, to use in my
forthcoming modular project. This one is only the PCB plus some
wires to the pots at the moment.
This is a picture of the one I build for my friend.

_________________
Sebo
---------------------------------------
My Music:
www.cosaquitosenglobo.com.ar
www.myspace.com/cosaquitosenglobo
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Wed Aug 15, 2007 11:46 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks, I have just added it to the Minimoog VCF clone gallery Very Happy
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
Sebo



Joined: Apr 27, 2007
Posts: 534
Location: Argentina

PostPosted: Wed Aug 15, 2007 12:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

Great !!!
Two things I like to share about the Minimoog VCF:

1- I used BC550 instead of BC547, because are less noisy. I matched
them using the transistor matcher that are in the Minimoog Service
Manual, I only change a resistor to run it off +15-15V instead of +10-10V
(as someone in this forum sugested). I'm not sure if the transistors are
well matched, because when I measure I get really close values, and
when I measure again (to double check) I never get the same reading.
I didn't touch the transistors with my hand. Most of the readings was
between 418 and 428 mV (in the Minimoog Service Manual the values
showed are about 910 mV). I tried to measure some 2N3904 (the ones
that the Minimoog uses), and I get the same readings.
The Filter works OK anyway, the only issue is that self-oscillation
decreases as I low the frequency. In my Moogerfooger I noticed the
same behavior but in a much less degree, and only in the lower
self-oscillating resonances (at full resonance the oscillation keeps the
same level across all the frequency range).
I matched the caps with a cheap multimeter, but I haven't any issue
here (I think).

2 - I made the inverse log pot for the resonance splitting 2 dual (stereo)
log pots and changing the back resistive track (small PCB) of one by the
front resistive track of the other. Cheap but works great (I only use
the back part of the resulting stereo pot).

I'm very happy with the filter.

_________________
Sebo
---------------------------------------
My Music:
www.cosaquitosenglobo.com.ar
www.myspace.com/cosaquitosenglobo
Back to top
View user's profile Send private message
softfin



Joined: Oct 11, 2006
Posts: 264
Location: Far in the north
Audio files: 1

PostPosted: Fri Aug 17, 2007 9:48 am    Post subject: Reply with quote  Mark this post and the followings unread

While we're on the subject, I'll tell you about my Yusynth Moog Vcf...
I etched the pcb using the layout on Yves' site, but added an expansion board for switchable (using a 4PDT switch) filter core caps, 22n (moog rogue, opus3 etc.) or 68n (minimoog). Another mod was to add a switch for 12db operation.

I also experimented with polypropylene caps and decided to built this filter with only polypropylene caps matched to 0.1%. I used metal can LM394s for the filter core transistor pairs.
I tried to make this filter as h-fi as I could and think I succeeded pretty well.
It sounds very defined, but also a bit colder and more sterile than my older Moog VCF though. For some reason, on 12db setting the resonance is lower than on 24db.

The older one has all filter core transistors from the same batch without matching and orange drop (polyester) 47n filter core caps matched to 1%, works great too with "browner sound' than the modded version.

I attached a pic of the finished 'hifi moog vcf', maybe it looks a bit harsh, but at least it works right Smile


yu_moogvcf_.jpg
 Description:
 Filesize:  119.74 KB
 Viewed:  12955 Time(s)

yu_moogvcf_.jpg


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



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Fri Aug 17, 2007 10:04 am    Post subject: Reply with quote  Mark this post and the followings unread

softfin wrote:
I also experimented with polypropylene caps and decided to built this filter with only polypropylene caps matched to 0.1%. I used metal can LM394s for the filter core transistor pairs.
I tried to make this filter as h-fi as I could and think I succeeded pretty well.
It sounds very defined, but also a bit colder and more sterile than my older Moog VCF though.

Somehow too perfect such that it looses the warmth of Moog...
Quote:

For some reason, on 12db setting the resonance is lower than on 24db.

It's the same problem with Synthesizers.com Q150, the resonance in 12dB mode is simply useless.

_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
Peake



Joined: Jun 29, 2007
Posts: 1106
Location: Loss Angeles
Audio files: 3

PostPosted: Fri Aug 17, 2007 10:33 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi, I have a noob question regarding FFB design...

I note that all (AFAIK) modern FFBs use active filters and not inductors. Why? Can't you just add makeup gain after the passive circuit, ala' API and Pultec EQs? I realized that you require a gain stage for each output setup you wish to use ("All", "Even"/"Odd", Individual) but even then, isn't it a much simpler circuit, and also has a timbre that active design does not achieve?
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Fri Aug 17, 2007 10:45 am    Post subject: Reply with quote  Mark this post and the followings unread

Peake wrote:
Hi, I have a noob question regarding FFB design...

I note that all (AFAIK) modern FFBs use active filters and not inductors. Why?
Cost ! Because for inductors with the right reactance and the right Q, you cannot use standard parts. You need to have them made for you especially and it's very expensive indeed compared to active filters.

Peake wrote:
also has a timbre that active design does not achieve?
The difference in timbre is due to the magnetic saturation properties of the inductor core. This introduces some kind of smooth distorsion that is channel dependant. I think one could add some non-linear distorsion circuits (with OTAs perhaps) after each active filter cell if one wants to retrieve such behaviour . But here it's mostly a matter of taste and choice : do one wants a circuit that mimics the sound of the 914 or does one wants a filter bank that behaves as it should theoretically ?
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
Peake



Joined: Jun 29, 2007
Posts: 1106
Location: Loss Angeles
Audio files: 3

PostPosted: Fri Aug 17, 2007 10:55 am    Post subject: Reply with quote  Mark this post and the followings unread

yusson wrote:
Cost ! Because for inductors with the right reactance and the right Q, you cannot use standard parts. You need to have them made for you especially and it's very expensive indeed compared to active filters.


Thanks. I know that some folks hand-wind transformers for themselves...

yusson wrote:
The difference in timbre is due to the magnetic saturation properties of the inductor core. This introduces some kind of smooth distorsion that is channel dependant. I think one could add some non-linear distorsion circuits (with OTAs perhaps) after each active filter cell if one wants to retrieve such behaviour . But here it's mostly a matter of taste and choice : do one wants a circuit that mimics the sound of the 914 or does one wants a filter bank that behaves as it should theoretically ?


Good points.. I'm a fan of big metal designs (Manley Variable-mu compressor, etc.) so I like the distortion that transformers (and now I know, inductors) produce. Thank you for the tips and the public designs.
Back to top
View user's profile Send private message
Funky40



Joined: Sep 24, 2005
Posts: 875
Location: Swiss
Audio files: 1
G2 patch files: 5

PostPosted: Mon Aug 20, 2007 8:09 am    Post subject: Reply with quote  Mark this post and the followings unread

Question about the Caps:

From 100 nF down to 6,8nF i got the MKS2-5,
but the smaller ones i had to take FKP-2 from WIMA to get 5%.


Is this a Problem that i have different Types of Caps mixed ? ( beside that they are much more expensive )


thanks in advance
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Mon Aug 20, 2007 9:30 am    Post subject: Reply with quote  Mark this post and the followings unread

Check with a capacimeter that the value are within 5% and it should be OK. What is important is that for one cell C1a+C1b is close to C2a+C2b (and the same for C3a+C3b and C4a+C4b). In my prototype I did not check the goodness of the match (I've been using caps from the same batch though) and I obtained a good result as seen on the spectra shown on my site.

Don't worry it should be alright...

_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
pm



Joined: Aug 17, 2008
Posts: 9
Location: belgrade

PostPosted: Thu Aug 21, 2008 3:57 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi

anyone have 914 filterbank schematic? Searched the net and the forum but no luck.

Thank you very much.
Back to top
View user's profile Send private message
guitarfool



Joined: Feb 26, 2007
Posts: 156
Location: Maryland
Audio files: 8

PostPosted: Thu Aug 21, 2008 4:16 pm    Post subject: Reply with quote  Mark this post and the followings unread

pm wrote:
Hi

anyone have 914 filterbank schematic? Searched the net and the forum but no luck.

Thank you very much.


Go to http://www.hylander.com/moogschematics.html and download the "Complete Moog Modular Service Manual". It's somewhere in the middle (along with everything else) Very Happy
Back to top
View user's profile Send private message Visit poster's website
pm



Joined: Aug 17, 2008
Posts: 9
Location: belgrade

PostPosted: Fri Aug 22, 2008 12:24 am    Post subject: Reply with quote  Mark this post and the followings unread

Got it.
Guitarfool thank you very much.
Back to top
View user's profile Send private message
numbertalk



Joined: May 05, 2008
Posts: 980
Location: Austin, TX
Audio files: 5

PostPosted: Thu Mar 19, 2009 6:30 am    Post subject: Reply with quote  Mark this post and the followings unread

I have a question - I have the Bridechamber panel for the FFB and the input level pot is also labeled as dry-wet - could someone who has built this version (or Yves perhaps you know) how do you wire this exactly? Is it like this:

http://www.modularsynthesis.com/yusynth/DJB-FFB_schematic_mods.jpg
http://www.modularsynthesis.com/yusynth/DJB-FFB_mod_summary.jpg

Where the input pot's CCW lug has an extra wire that connects it to the
3 bypass throws on the active/bypass switch? I'm not sure how
this works out as a wet/dry mix control, then, since this throw won't
be connected to the outputs when the switch is in the active position. Also when the bypass switch is in "active" mode, then the dry input seems to be disconnected from the outputs. So it seems dry & wet are mutually exclusive settings/modes that can't be mixed given this wiring, so I'm thinking something different is required but I can't work out what.

Any help very much appreciated.

Last edited by numbertalk on Thu Mar 19, 2009 8:12 am; edited 1 time in total
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Thu Mar 19, 2009 7:04 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi

I am not responsible for this mod and from what I see on the mod schematics I have no problem to see how the bypass switches operate but I don't understand how the wet/dry pot would operate. What I see here is only a simple input level pot, not a balance pot between unprocessed and processed signal. Ask Scott Deyo what he had in mind when he designed the panel...

For such a wet/dry function here is what I would do : first I'd disconnect the ALL output jack from SW1A, then I'd connect the ALL output jack to the wiper lug of the pot, the CCW to the direct input and the CW to the center lug of SW1A. This mod in mid position would turn the FFB into a kind of equalizer (I think it's a boring mod)

I would also try a 470K lin pot for this rather than a 100K.

_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
numbertalk



Joined: May 05, 2008
Posts: 980
Location: Austin, TX
Audio files: 5

PostPosted: Thu Mar 19, 2009 7:27 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves, thanks for the quick response! I did ask Scott, but he's been too busy to get back to me about it. I'm not that hung up on it - now that you mention it I don't think I will bother - I'll just wire it as an input level control, like it is in that bypass mod diagram.
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1219
Location: France

PostPosted: Thu Mar 19, 2009 8:08 am    Post subject: Reply with quote  Mark this post and the followings unread

By the way on the mod schemo, the CCW lug of the pot is connected to ground although the symbol used (a hollow down arrow) normally refers to the negative rail in my schematic...
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
numbertalk



Joined: May 05, 2008
Posts: 980
Location: Austin, TX
Audio files: 5

PostPosted: Fri Mar 20, 2009 10:07 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks Yves!

yusynth wrote:
By the way on the mod schemo, the CCW lug of the pot is connected to ground although the symbol used (a hollow down arrow) normally refers to the negative rail in my schematic...
Back to top
View user's profile Send private message
davebr



Joined: Jun 09, 2007
Posts: 181
Location: portland, or

PostPosted: Sun Nov 08, 2009 9:15 pm    Post subject: Fixed Filter Bank
Subject description: Website
Reply with quote  Mark this post and the followings unread

I guess I never posted to this topic. I completed mine quite some time ago and have some documentation on my website.
http://modularsynthesis.com/yusynth/ffb.htm
Dave
Back to top
View user's profile Send private message
neandrewthal



Joined: May 11, 2007
Posts: 672
Location: Canada

PostPosted: Sat Dec 05, 2009 10:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

I just finished mine too. I love it! Many thanks. Very Happy


IMG_9376.JPG
 Description:
 Filesize:  773.88 KB
 Viewed:  175 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

IMG_9376.JPG



_________________
" I went through quite a few trannies til I found one I liked" - Wild Zebra
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 2 [34 Posts]
View unread posts
View new posts in the last week
Goto page: 1, 2 Next
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » YuSynth
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