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 
Live streaming at radio.electro-music.com

  host / artist show at your time
  EdisonRex Edison's Electronic Review
Please visit the chat
 Forum index » DIY Hardware and Software » YuSynth
YUSYNTH EMS-diode ladder filter
Post new topic   Reply to topic Moderators: Scott Stites
Page 4 of 6 [129 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: Previous 1, 2, 3, 4, 5, 6 Next
Author Message
yusynth



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Fri Oct 30, 2009 12:06 am    Post subject: Reply with quote  Mark this post and the followings unread

Scot Solida wrote:
I just finished building this one tonight. At first, it didn't work properly, but using the 220 resistor as described above did the trick. It sounds terrific! I am using it in my Dotcom system, but I left R8 alone. for now. The input control knob should be enough for my needs. It won't do any harm will it?

In any event, I still need to mount the PCB to the panel. After that, I will do some A/B comparisons with my VCS3. I'll post the results in another thread.


No harm will be done, the worst thing that may occur is overdrive and distorsion.

For the comparison with the VCS3 be sure to use comparable input levels.

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



Joined: Oct 24, 2009
Posts: 96
Location: Hutchinson Kansas

PostPosted: Fri Oct 30, 2009 4:20 am    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:


No harm will be done, the worst thing that may occur is overdrive and distorsion.

For the comparison with the VCS3 be sure to use comparable input levels.


That's what I suspected, and one of the reasons I left it "as is". It never hurts to have the option of a little overdrive and distortion in the signal path sometimes.
Back to top
View user's profile Send private message
Scot Solida



Joined: Oct 24, 2009
Posts: 96
Location: Hutchinson Kansas

PostPosted: Sat Oct 31, 2009 12:34 pm    Post subject: Reply with quote  Mark this post and the followings unread

I finally got around to A/B'ing the VCS3 with the YuSynth Diode Filter, and they sound very much alike, indeed. Any differences might be put down to input level and maybe my rather sloppy calibration of the YuSynth module. I noted that the VCS3 tended to more easily fluctuate in signal level with different res/cutoff values, and it was quicker to distort my Dotcom oscillators at low cutoff/high res settings. Still, the character is very, very similar to the real VCS3 filter. Nice work, Yves!
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Sat Oct 31, 2009 1:28 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Scot

Thanks for the comparison and it confirms what some other owners of Synthi who have built the yusynth diode filter told me before. Enjoy it Wink

I just had the opportunity to read the service manual of the JEN SX2000 and the VCF of this machine is an exact replica of the EMS filter ! It would be interesting to kbow if there has some collaboration between EMS and Jen back in those days ?

_________________
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: Sun Nov 01, 2009 10:12 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves,

Your BOM lists 5 100nf caps but I see 6 on the layout. Just making sure one of the ones on the layout isn't mislabeled.

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



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Sun Nov 01, 2009 10:54 am    Post subject: Reply with quote  Mark this post and the followings unread

There are six 100nF, I will correct the BOM ASAP.
_________________
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: Sun Nov 01, 2009 10:58 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks!
Back to top
View user's profile Send private message
Scot Solida



Joined: Oct 24, 2009
Posts: 96
Location: Hutchinson Kansas

PostPosted: Sun Nov 01, 2009 1:13 pm    Post subject: Reply with quote  Mark this post and the followings unread

If you get the bridechamber kit, it'll come with five 100nF. Mine did, anyway. Easy enough to replace, though.

I did notice a couple of things about the filter: when using a Synthesizers.com ADSR to drive the Cutoff, I usually need to boost the signal through the Signal Processor module first. I noticed that this is also the case with the STG "Post Lawsuit Filter" (also a YuSynth design). Is this something I am doing wrong, or is there a mod to fix it? If not, it's no big deal, since I have a couple of signal processor modules.
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Sun Nov 01, 2009 3:09 pm    Post subject: Reply with quote  Mark this post and the followings unread

Scot Solida wrote:
I did notice a couple of things about the filter: when using a Synthesizers.com ADSR to drive the Cutoff, I usually need to boost the signal through the Signal Processor module first. I noticed that this is also the case with the STG "Post Lawsuit Filter" (also a YuSynth design). Is this something I am doing wrong, or is there a mod to fix it? If not, it's no big deal, since I have a couple of signal processor modules.


That's an interesting remark and it makes sense too since the inputs are all calibrated in V/Oct therefore 5V is 5 octave ! I did not notice that because I am using the YUSYNTH ADSR which provides an ADSR signal in the 0V-10V range while the DOTCOM ADSR is providing a CV in the range 0V-5V.

The fix is simple in the EMS filter change R15 (if you use this CV input for the ADSR) by a 47K resistor and for the Post Lawsuit, the trick is the same change the input resistor of the CV channel you are using by a resistor with half the value.

_________________
Yves

Last edited by yusynth on Sun Nov 01, 2009 3:30 pm; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
Scot Solida



Joined: Oct 24, 2009
Posts: 96
Location: Hutchinson Kansas

PostPosted: Sun Nov 01, 2009 3:26 pm    Post subject: Reply with quote  Mark this post and the followings unread

Brilliant! Thanks Yves. That does indeed make perfect sense. I'll swap them out tomorrow.
Back to top
View user's profile Send private message
numbertalk



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

PostPosted: Sun Nov 01, 2009 3:58 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves,

I'm about to build this so good timing since I use MOTM and Oakley ADSRs. Also building your Arp filter soon - would a similar substitution need to be made on that board too?

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



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Sun Nov 01, 2009 4:15 pm    Post subject: Reply with quote  Mark this post and the followings unread

Yes both MOTM and Oakley use 0-5V ADSR, therefore the mod is valid.
_________________
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: Sun Nov 01, 2009 5:26 pm    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:
Yes both MOTM and Oakley use 0-5V ADSR, therefore the mod is valid.


just to be clear does your arp vcf require a similar mod in this situation and if so which resistor and what value?

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



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Mon Nov 02, 2009 12:38 am    Post subject: Reply with quote  Mark this post and the followings unread

Exactly the same for both.
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
Thalassa



Joined: Jan 27, 2006
Posts: 95
Location: Spain
Audio files: 5

PostPosted: Mon Nov 02, 2009 1:48 am    Post subject: Reply with quote  Mark this post and the followings unread

It's strange I've built both filters and I can drive the cut-off frequency with a Synthesizers.com ADSR without problems. I have Yusynth ADSR also so I will try to make a face to face comparative.
Back to top
View user's profile Send private message Visit poster's website
yusynth



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Mon Nov 02, 2009 2:39 am    Post subject: Reply with quote  Mark this post and the followings unread

Thalassa wrote:
It's strange I've built both filters and I can drive the cut-off frequency with a Synthesizers.com ADSR without problems. I have Yusynth ADSR also so I will try to make a face to face comparative.


Hi Thalassa
the DOTCOM Q109 can be configured by adding a jumper on the board (J4 OUTPUT SWING : ON, -5V TO +5V OUTPUT, OFF 0V TO +5V OUTPUT) may be yours have a jumper installed.

http://www.synthesizers.com/q109adata.pdf

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



Joined: Jan 27, 2006
Posts: 95
Location: Spain
Audio files: 5

PostPosted: Mon Nov 02, 2009 3:16 am    Post subject: Reply with quote  Mark this post and the followings unread

I didn't make the mod and the factory default is 0V to 5V so mine should be configured that way.

Maybe is just that what I considered normal modulation for other people is not. So ...what I have now with the CV pot at maximum will be what i will get with the CV pot on middle position if I change the resistor value to 47k. am I right?
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: Mon Nov 02, 2009 4:02 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks Yves. So R30 and R31 on the Arp VCF? 47K?

I have also built your Minimoog VCF as well and am assuming I should make the same change here too? R7 to 47K right?
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Mon Nov 02, 2009 4:56 am    Post subject: Reply with quote  Mark this post and the followings unread

numbertalk wrote:
Thanks Yves. So R30 and R31 on the Arp VCF? 47K?

I have also built your Minimoog VCF as well and am assuming I should make the same change here too? R7 to 47K right?


Yes, you have it all good Wink

_________________
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: Mon Nov 02, 2009 5:35 am    Post subject: Reply with quote  Mark this post and the followings unread

Great thanks!
Back to top
View user's profile Send private message
numbertalk



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

PostPosted: Sun Nov 22, 2009 1:59 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves,

Just finished the filter and I too am having an issue with the resonance. I'm already using a 220K resistor but not really getting any resonance, just a slight change in sound, and definitely no self-oscillation. The 100uf cap is oriented correctly. Also I checked the voltages at the G of the FET and it's only varying between 0V to -2.9V - sounds like with the 220K resistor that should be getting down to -5V. Any ideas?

Thanks for the help.

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



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Sun Nov 22, 2009 2:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

numbertalk wrote:
Hi Yves,

Just finished the filter and I too am having an issue with the resonance. I'm already using a 220K resistor but not really getting any resonance, just a slight change in sound, and definitely no self-oscillation. The 100uf cap is oriented correctly. Also I checked the voltages at the G of the FET and it's only varying between 0V to -2.9V - sounds like with the 220K resistor that should be getting down to -5V. Any ideas?

Thanks for the help.

Paul


Hi Paul

First if you are using a Bridechamber kit make yourself sure that the FET is a 2N3819 (I know that in the early version of the kit Bridechamber did provide a wrong substitute FET) it must be a 2N3819. If it is a 2N3819 and the 220K resistor does not provide the resonance and oscillation you may reduce its value : try 180K or 150k this should do the trick.

By the way the voltages you measured are correct but FET transistor characteristics are very dispersed. Should I redesign this PCB I would replace this resistor by a trimmer for sure !

_________________
Yves

Last edited by yusynth on Wed Nov 25, 2009 8:02 am; edited 1 time in total
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: Sun Nov 22, 2009 6:01 pm    Post subject: Reply with quote  Mark this post and the followings unread

Thanks Yves.

So with a 150K resistor there it oscillates! However, the resonance still seems a little odd - it doesn't seem to add much to the sound of the filter - from 0 up until around 8-9 you can't hear anything added, then right before it breaks into oscillation it gets quieter, then it breaks into oscillation. Does this sound right to you? Should I lower the value of this resistor even more? Right now I'm measuring around -3.9V at the gate of the FET (and I sourced the parts myself so it's the right transistor here).

Plus I added a switch with that 10uf electrolytic cap in parallel with R22 for the "bubbling" mod, but I don't notice any difference with it switched in. How do you get this sound with that cap in place? Is this also possibly related to my potential resonance issue?

By the way I built the CA3096 version.

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



Joined: Nov 24, 2005
Posts: 1214
Location: France

PostPosted: Mon Nov 23, 2009 12:05 am    Post subject: Reply with quote  Mark this post and the followings unread

numbertalk wrote:
Thanks Yves.

So with a 150K resistor there it oscillates! However, the resonance still seems a little odd - it doesn't seem to add much to the sound of the filter - from 0 up until around 8-9 you can't hear anything added, then right before it breaks into oscillation it gets quieter, then it breaks into oscillation. Does this sound right to you? Should I lower the value of this resistor even more? Right now I'm measuring around -3.9V at the gate of the FET (and I sourced the parts myself so it's the right transistor here).

Plus I added a switch with that 10uf electrolytic cap in parallel with R22 for the "bubbling" mod, but I don't notice any difference with it switched in. How do you get this sound with that cap in place? Is this also possibly related to my potential resonance issue?

By the way I built the CA3096 version.

Thanks again.


Considering the value of the resistor, the voltage measeured are normal.
What is the level of the signal you input in the circuit ? The sound and behaviour depends a lot on the input levels (that's why there are input level pots). If you use yusynth or dotcom VCO you must attenuate (around mark 4) the input signal in order to obtain the typical EMS sound.

To "hear" the effect of the bubling mod you must modulate the filter with a fast enveloppe. The cap acts as a slew limiter on the CV input. This mod was added because some people asked for it. They wanted the filter to behave exactly like the filter in the AKS MkI but in my humble opinion it is of minor interest and actually was a design mistake that was corrected/suppressed by EMS designer in their version MkII.

_________________
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: Mon Nov 23, 2009 4:31 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm using a 10Vp-p VCO. I changed that 1 input mixer resistor like you mentioned - with this change do I still need to attenuate to around 4? Maybe because of this resistor change and with the input pot being log taper I noticed earlier when I would attenuate the input signal the signal seems to drop in and out as I attenuate from 10.

EDIT - To be clear I changed R8 to 27K. I see Suit & Tie Guy also changed the 2.2K shunt to ground to 220R - should I do this as well? Or should I just change R8 back and use just the input pot to attenuate the signal? I'm thinking possibly something else is going on since I'm guessing having changed R8 as you specified with the input pot turned up all the way I should get good resonance.

Also, if there was an issue with the FET being dead I wouldn't be getting oscillation, right? I just tried playing around with the input level pot and I get some resonance, but unless it's on the brink of oscillation it's really really subtle - from about 0-9 on the resonance pot doesn't add much.

Thanks.

yusynth wrote:
numbertalk wrote:
Thanks Yves.

So with a 150K resistor there it oscillates! However, the resonance still seems a little odd - it doesn't seem to add much to the sound of the filter - from 0 up until around 8-9 you can't hear anything added, then right before it breaks into oscillation it gets quieter, then it breaks into oscillation. Does this sound right to you? Should I lower the value of this resistor even more? Right now I'm measuring around -3.9V at the gate of the FET (and I sourced the parts myself so it's the right transistor here).

Plus I added a switch with that 10uf electrolytic cap in parallel with R22 for the "bubbling" mod, but I don't notice any difference with it switched in. How do you get this sound with that cap in place? Is this also possibly related to my potential resonance issue?

By the way I built the CA3096 version.

Thanks again.


Considering the value of the resistor, the voltage measeured are normal.
What is the level of the signal you input in the circuit ? The sound and behaviour depends a lot on the input levels (that's why there are input level pots). If you use yusynth or dotcom VCO you must attenuate (around mark 4) the input signal in order to obtain the typical EMS sound.

To "hear" the effect of the bubling mod you must modulate the filter with a fast enveloppe. The cap acts as a slew limiter on the CV input. This mod was added because some people asked for it. They wanted the filter to behave exactly like the filter in the AKS MkI but in my humble opinion it is of minor interest and actually was a design mistake that was corrected/suppressed by EMS designer in their version MkII.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 4 of 6 [129 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2, 3, 4, 5, 6 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
mps board

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