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 EMS-diode ladder filter
Post new topic   Reply to topic Moderators: Scott Stites
Page 3 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: 1233
Location: France

PostPosted: Mon Dec 22, 2008 3:49 am    Post subject: Reply with quote  Mark this post and the followings unread

OK 220K Wink Then the voltage swing is weird it should stay below 0V and at least go down to -2.4V. Is some kind of voltage fed at the resonance CV input ?

Question : which version are you using the CA3096 version (U5) or the tranny version.

_________________
Yves

Last edited by yusynth on Mon Dec 22, 2008 9:01 am; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
stijn



Joined: Jul 21, 2008
Posts: 39
Location: utrecht, netherlands

PostPosted: Mon Dec 22, 2008 8:42 am    Post subject: Reply with quote  Mark this post and the followings unread

I have the descrete version. (bridechamber kit)
there is no voltage at the cv control for the resonance
Back to top
View user's profile Send private message
stijn



Joined: Jul 21, 2008
Posts: 39
Location: utrecht, netherlands

PostPosted: Tue Dec 30, 2008 7:06 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Ives, it turned out that the bridechamber kit has a PN4391 insted of a 2N3819 jfet, wich has a different pin out. So I desolderded it (wich was quite a hasle, are there any tricks fot this besides a solder sucker?) and flipped it but now I have no resonance at all, so I guess it's broken?
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Tue Dec 30, 2008 7:48 am    Post subject: Reply with quote  Mark this post and the followings unread

stijn wrote:
Hi Ives, it turned out that the bridechamber kit has a PN4391 insted of a 2N3819 jfet, wich has a different pin out. So I desolderded it (wich was quite a hasle, are there any tricks fot this besides a solder sucker?) and flipped it but now I have no resonance at all, so I guess it's broken?


I see, you should let know this to Scott Deyo because he provided you with a component that is not pin to pin compatible with the 2N3819...

It may not be broken but have a different pinch voltage than expected. As I explained on my page the characteristics of the pinch voltage of a JFET brand are very dispersed. JFETs are not as reliable in terms of charateristics as can be BJT transistors and picking two JFETs from the same batch may give very different results. Here it's even more different because you have a different brand of JFET...

What you can do is to take a 47K resistor and connect it in parallel with R41, and see if there is an improvement of the resonance control. If you recover the resonance control then try using other values in order to find the one that gives you full range. Otherwise, that is if with the 47K resistor you don't recover the resonance control, then your JFET is dead and replace it (preferably with a 2N3819 Wink )

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



Joined: Jan 17, 2009
Posts: 10
Location: Chicago

PostPosted: Wed Jan 21, 2009 10:49 am    Post subject: Reply with quote  Mark this post and the followings unread

Here's a dumb question from a new DIY'er...i'd like to purchase this and build it. I do have building experience, and can SORT of read a schematic. My question is more mechanical...is the PCB small enough to fit in a Doepfer A100 case and will it run at +/- 12v, and if so, how would i go about making this happen?
_________________
Time is an illusion. Lunchtime doubly so.
Back to top
View user's profile Send private message AIM Address
yusynth



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Wed Jan 21, 2009 12:27 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Chaorta and welcome

Concerning the PCB I can't tell you because I have no Doepfer case to check it. But may be if give the size of the PCB you can make yourself an idea. The PCB is 10 cm per 7.5 cm and has four fixation holes.

Concerning the power supply, yes it will run at +12V/-12V, for this you just need to remove some components : remove R3 (82ohm) and bypass its pads with a wire, remove U2 (78L12/7812) bypass with an insulated wire the left and rigth pads (leave the middle pad unconnected) and that's it (see the diagram below : left before mod, right : after mod, bypass wires shown in red)


diode-vcf-mof.gif
 Description:
 Filesize:  43.57 KB
 Viewed:  195 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

diode-vcf-mof.gif



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



Joined: Jan 17, 2009
Posts: 10
Location: Chicago

PostPosted: Wed Jan 21, 2009 1:47 pm    Post subject: Reply with quote  Mark this post and the followings unread

Well that was easy, thanks Smile
_________________
Time is an illusion. Lunchtime doubly so.
Back to top
View user's profile Send private message AIM Address
softfin



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

PostPosted: Sat Feb 07, 2009 10:51 am    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:
Hi Chaorta and welcome

Concerning the PCB I can't tell you because I have no Doepfer case to check it. But may be if give the size of the PCB you can make yourself an idea. The PCB is 10 cm per 7.5 cm and has four fixation holes.

Concerning the power supply, yes it will run at +12V/-12V, for this you just need to remove some components : remove R3 (82ohm) and bypass its pads with a wire, remove U2 (78L12/7812) bypass with an insulated wire the left and rigth pads (leave the middle pad unconnected) and that's it (see the diagram below : left before mod, right : after mod, bypass wires shown in red)


Finished my pair of diode ladders. I put them in my +-12V case, so I did the suggested modifications, but found the -9V was only about -7.25V, so I exchanged R4 with a 120ohm resistor and also replaced R50 with 5k trimmer as a voltage divider. I didn't measure the resistance of the trimmer when I achieved precise -9V, but it is probably around 2k.

These long awaited filters have this excellent spiky but pleasing character. The only downside seems to be CV bleedthrough which is louder than on my other filters. Is there any simple way to reduce it?

Btw, six diodes are reversed on the overlay with the color coded resistors.

Big thanks to Yves for this module!
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Sat Feb 07, 2009 11:00 am    Post subject: Reply with quote  Mark this post and the followings unread

softfin wrote:
These long awaited filters have this excellent spiky but pleasing character. The only downside seems to be CV bleedthrough which is louder than on my other filters. Is there any simple way to reduce it?

Btw, six diodes are reversed on the overlay with the color coded resistors.

Big thanks to Yves for this module!


Did you match thorougly your diodes ? This is important to reduce the CV bleedthrough.

Concerning, the overlay error, this has been corrected on my site at least two months ago Wink

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



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

PostPosted: Sat Feb 07, 2009 1:48 pm    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:


Did you match thorougly your diodes ? This is important to reduce the CV bleedthrough.

Concerning, the overlay error, this has been corrected on my site at least two months ago Wink


I used the layouts I had archived some time ago, so I didn't notice the layout was already corrected. Shocked

Regarding the diodes, I took a strip of factory packed diodes and measured them simply by putting +9V across each one and measured the voltage drop. All diodes had almost exactly the same amount of voltage drop, the difference in drop between diodes being 0.01-0.02V. That was also pretty much as precise a measurement as possible on my multimeter.

Should I match them more carefully, and if so, is there a more precise method you could recommend?
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Sat Feb 07, 2009 2:54 pm    Post subject: Reply with quote  Mark this post and the followings unread

Yes you should... as a matter of fact they must be matched by pair within 2mV. The bleedthrough mostly comes for the unbalance between each side of the ladder. The principle of this kind of ladder is that the CV is canceled out by subtracting the left and right side of te ladder while the audio passes through because it is differentially transmitted by the input transistors.
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
softfin



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

PostPosted: Sun Feb 08, 2009 9:06 am    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:
Yes you should... as a matter of fact they must be matched by pair within 2mV. The bleedthrough mostly comes for the unbalance between each side of the ladder. The principle of this kind of ladder is that the CV is canceled out by subtracting the left and right side of te ladder while the audio passes through because it is differentially transmitted by the input transistors.


Thanks for the explanation, it makes perfect sense.

Since I couldn't get enough precision using my 'better' multimeter, I tried matching the diodes again with a lower voltage (1.6V) and using my old, cheapish DVM which actually allowed me to measure the voltage drop more precisely in millivolts.
So I matched diodes to 1mv and replaced all diodes in the ladders of both of my units. It seems cv bleedthru decreased considerably, but it is still audible.
I suppose I should get a better quality multimeter, if I want to have more precise and stable readings.
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Sun Feb 08, 2009 9:59 am    Post subject: Reply with quote  Mark this post and the followings unread

softfin wrote:

So I matched diodes to 1mv and replaced all diodes in the ladders of both of my units. It seems cv bleedthru decreased considerably, but it is still audible.
I suppose I should get a better quality multimeter, if I want to have more precise and stable readings.


Well as a matter of fact it would be difficult to get better with the matching of diodes. Now the next points to take care of are :
1°) try using different CA3046 (the matching of the differential transistor pair may vary from a chip to another : by the way avoid Thailand labelled brand they are very bad)
2°) if you are using the discrete version check the match of the BC557 pair and of BC547 pair, if you are using the CA3096 try different ICs.

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



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

PostPosted: Sun Feb 08, 2009 3:46 pm    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:

1°) try using different CA3046 (the matching of the differential transistor pair may vary from a chip to another : by the way avoid Thailand labelled brand they are very bad)
2°) if you are using the discrete version check the match of the BC557 pair and of BC547 pair, if you are using the CA3096 try different ICs.


I tested if different transistor arrays would lower the cv bleedthru. There was no noticeable difference between Harris, Intersil or RCA 3046s and 3086s I tested.
I matched the BC557s and BC547 to very small difference in hfe, so I think they're ok.

I don't know is it my ears or is it for real, but the bleedthru seems to increase when I lower the resonance. I attached a clip to illustrate this.


kleeems.mp3
 Description:

Download
 Filename:  kleeems.mp3
 Filesize:  2.9 MB
 Downloaded:  431 Time(s)

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



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Sun Feb 08, 2009 4:04 pm    Post subject: Reply with quote  Mark this post and the followings unread

from your sample I'd say that you won't get a better result. As a matter of fact you could add a 100pF to 1nf cap in parallel with R22 to create just enough slew to attenuate the bump on fast attacks (this trick was used in the Minimoog filter).
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
softfin



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

PostPosted: Sun Feb 08, 2009 4:37 pm    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:
from your sample I'd say that you won't get a better result. As a matter of fact you could add a 100pF to 1nf cap in parallel with R22 to create just enough slew to attenuate the bump on fast attacks (this trick was used in the Minimoog filter).



Ok. I'll add the cap and perhaps a switch too, so I'll have the possibility to add just a bit of thump/click to the sound when I need it.

Thanks for your help.
Back to top
View user's profile Send private message
numbertalk



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

PostPosted: Mon Feb 09, 2009 8:54 am    Post subject: Reply with quote  Mark this post and the followings unread

What a great sounding filter! This has been in my build queue for a while but think I need to bump up its priority a bit Smile
Back to top
View user's profile Send private message
stijn



Joined: Jul 21, 2008
Posts: 39
Location: utrecht, netherlands

PostPosted: Wed Apr 08, 2009 1:32 am    Post subject: Reply with quote  Mark this post and the followings unread

ok Yves, I finally got the right jfet , I put it in but in all my exitement
hooked up the power in the wrong way Embarassed
so something got fried. can u tell me wich parts I should replace to make it work again?
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Wed Apr 08, 2009 10:22 am    Post subject: Reply with quote  Mark this post and the followings unread

stijn wrote:
ok Yves, I finally got the right jfet , I put it in but in all my exitement
hooked up the power in the wrong way Embarassed
so something got fried. can u tell me wich parts I should replace to make it work again?


Ouch... This is a great classic and it also happened to me a couple of time... Embarassed
The following ICs and trannies may have fried (ordered from most certain death to may have survived) :
the 7812/78L12 regulator has probably been fried
the BC327 is also probably dead
the other ICs (TL074) and trannies have probably survived because the regulator died first, but I would replace the TL074 which doesn't like reverse power !
Did you see a fume ?

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



Joined: Jul 21, 2008
Posts: 39
Location: utrecht, netherlands

PostPosted: Thu Apr 09, 2009 12:04 am    Post subject: Reply with quote  Mark this post and the followings unread

tnx for the fast reply Yves.

ooh and yes there was a fume!
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 Oct 08, 2009 7:30 pm    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:

Here is a tip : for those of you who want to obtain a genuine EMS sound while using DOTCOM or YUSYNTH VCOs it is recommended to change the value of R8 to 27K. The output levels of these VCOs are much higher than those of an AKS and this makes a big difference in sound.


Hi Yves,

I notice on the schematic you also flag R9 as being changed in addition to R8. What value would you suggest changing R9 to? I don't have dotcom or yusynth vcos but my vcos are 10Vp-p, so I'm guessing I'd want to change these 2 resistors as well.

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



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Thu Oct 08, 2009 11:18 pm    Post subject: Reply with quote  Mark this post and the followings unread

numbertalk wrote:
yusynth wrote:

Here is a tip : for those of you who want to obtain a genuine EMS sound while using DOTCOM or YUSYNTH VCOs it is recommended to change the value of R8 to 27K. The output levels of these VCOs are much higher than those of an AKS and this makes a big difference in sound.


Hi Yves,

I notice on the schematic you also flag R9 as being changed in addition to R8. What value would you suggest changing R9 to? I don't have dotcom or yusynth vcos but my vcos are 10Vp-p, so I'm guessing I'd want to change these 2 resistors as well.

Thanks!


Hi if you have 10Vpp VCOs then it's the same as for YUSYNTH or DOTCOM VCOS, use 27K for R8 and leave R9 unchanged.
What is shown on the schematic is that one may modify either R8 or R9, or both to achieve the desired attenuation of the signal.
In your case you only need to change R8 as mentioned in the quote above.

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



Joined: Jan 03, 2006
Posts: 66
Location: new york

PostPosted: Fri Oct 09, 2009 2:20 am    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:

Here is a tip : for those of you who want to obtain a genuine EMS sound while using DOTCOM or YUSYNTH VCOs it is recommended to change the value of R8 to 27K. The output levels of these VCOs are much higher than those of an AKS and this makes a big difference in sound.


I could see doing that if for practical purposes all your VCOs had every waveform ranged +-10v, but considering the original EMS has level pots out of the VCO I'd think an variable attenuator would be more ideal than adding more fixed attenuation.
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1233
Location: France

PostPosted: Fri Oct 09, 2009 2:33 am    Post subject: Reply with quote  Mark this post and the followings unread

ndkent wrote:

I could see doing that if for practical purposes all your VCOs had every waveform ranged +-10v, but considering the original EMS has level pots out of the VCO I'd think an variable attenuator would be more ideal than adding more fixed attenuation.

As a matter of fact the yusynth EFM-filter already has such INPUT LEVEL pots in order to be able to process signal from a wide range of VCOs :


diode-VCF-module.jpg
 Description:
 Filesize:  105.62 KB
 Viewed:  7852 Time(s)

diode-VCF-module.jpg



_________________
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: Thu Oct 29, 2009 6:34 pm    Post subject: Reply with quote  Mark this post and the followings unread

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.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 3 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
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