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
  mosc Chez mosc - tonight, Twyndyllyngs live
Please visit the chat
 Forum index » DIY Hardware and Software » YuSynth
Need help with YU-Synth Arp 4072 VCF
Post new topic   Reply to topic Moderators: Scott Stites
Page 3 of 4 [86 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 Next
Author Message
Thalassa



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

PostPosted: Tue Oct 13, 2009 11:16 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks Yves, very fast and useful answer as always Smile
_________________
http://www.corsynth.com
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 6:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves,

I can't find a 2K2 multi-turn - it's either 2K or 5K. Should I get the 5K? I'm just concerned that 2K won't be enough.

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



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

PostPosted: Mon Nov 02, 2009 12:40 am    Post subject: Reply with quote  Mark this post and the followings unread

2K is OK
_________________
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 1:01 am    Post subject: Reply with quote  Mark this post and the followings unread

I had the same doubt so I used three pin socket just in case that I had to change the resistor. I've tried both values and I can tell you that I could get 1V/Oct tracking with both. I think that now I have the 2K resistor installed on my filter and works very well, I have good tracking within almost 5 octv.
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 4:05 am    Post subject: Reply with quote  Mark this post and the followings unread

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



Joined: Jul 25, 2008
Posts: 40
Location: Melbourne, Australia

PostPosted: Sun Mar 14, 2010 5:46 am    Post subject: Reply with quote  Mark this post and the followings unread

just finished building this filter, using a pcb from bridechamber - sounds GREAT! can't wait to compare it to the arp omni i have at the studio...

the pcb was very easy and quick to put together, only took me a few hours to from blank pcb to finished module with the pots and jacks etc - once i realised the output silkscreen was reversed! Very Happy

thanks Yves!
Back to top
View user's profile Send private message
chroos



Joined: Feb 23, 2009
Posts: 5
Location: germany

PostPosted: Thu Sep 30, 2010 8:24 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi.. in Thalassas video i can hear the signals high frequencies (very quiet) in the background when the resonance pot is in mid range (3.30min). I recognized this on my module, too.

This unfilted signal does not seem to be present on the original filter. As far i can hear it in the video.

Is this the way this filter should work?

EDIT:

I think i fixed this:

I took the signal after R6 and put it to the node between R8 and Q1. I changed R6 to 22K to dont loose the current.

This way the unfiltered signal cant flow through the resonance part.
I can now use the resonance pot in all ranges, without having the unfiltered signal in it.

Would someone verify this?
Back to top
View user's profile Send private message
LektroiD



Joined: Aug 23, 2008
Posts: 975
Location: Scottish Borders
Audio files: 2
G2 patch files: 2

PostPosted: Sat Dec 04, 2010 2:43 am    Post subject: Reply with quote  Mark this post and the followings unread

How easy would it be to add a resonance FM socket?
_________________
My tunes available here
(check out the new Electro-Funk LP)
Back to top
View user's profile Send private message Visit poster's website
yusynth



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

PostPosted: Sat Dec 04, 2010 3:04 am    Post subject: Reply with quote  Mark this post and the followings unread

LektroiD wrote:
How easy would it be to add a resonance FM socket?

I gather that you mean a CV resonance socket ?
It would request a complete redesign to include some kind of OTA VCA in the resonance loop or a JFET circuit like in the EMS filter. In anay case you would need an extra board for that.

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



Joined: Aug 23, 2008
Posts: 975
Location: Scottish Borders
Audio files: 2
G2 patch files: 2

PostPosted: Tue Dec 07, 2010 12:44 pm    Post subject: Reply with quote  Mark this post and the followings unread

How would I go about switching between 2 & 4 poles?

I'm assuming it would be a case of shorting a couple of pins of the LM3900 where 2 of the the poles input with a switch? Maybe pins 10 & 4, or 5 & 9, leaving just 2 of the poles active? This is just a guess..

_________________
My tunes available here
(check out the new Electro-Funk LP)
Back to top
View user's profile Send private message Visit poster's website
Sebo



Joined: Apr 27, 2007
Posts: 525
Location: Argentina

PostPosted: Sat Jan 15, 2011 7:01 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves:
I just finished my ARP4072 VCF, it sounds amazing, it's becoming my fab VCF.
It's self oscillate way over the 20Hz-20KHz range.
One thing is annoying me is that when the resonance is anything but 0 I get
some signal bleedthought. When resonance is at 0 the bleeding disappears.
Naturally the bleeding isn't audible when the filter is open, but when it is closed
I can hear a very small portion of the input signal.
Any ideas of what could be wrong?
Thank you.

PD: I forgot to mention that I used the BC557 layout, but used 2N5087 transistors (as used originally by ARP) just because I found some.

_________________
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: 1214
Location: France

PostPosted: Sun Jan 16, 2011 1:48 am    Post subject: Reply with quote  Mark this post and the followings unread

Sebo wrote:
Hi Yves:
I just finished my ARP4072 VCF, it sounds amazing, it's becoming my fab VCF.
It's self oscillate way over the 20Hz-20KHz range.
One thing is annoying me is that when the resonance is anything but 0 I get
some signal bleedthought. When resonance is at 0 the bleeding disappears.
Naturally the bleeding isn't audible when the filter is open, but when it is closed
I can hear a very small portion of the input signal.
Any ideas of what could be wrong?
Thank you.

PD: I forgot to mention that I used the BC557 layout, but used 2N5087 transistors (as used originally by ARP) just because I found some.


Hi Sebo

What do you use as an input signal : amplitude Vpp, shape and frequency (pitch) ? I need to know these in order to run a test on my filter at home.
What is the amount of the bleedthrough ?

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



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

PostPosted: Sun Jan 16, 2011 1:49 am    Post subject: Reply with quote  Mark this post and the followings unread

By the way are all ground connections of the module correctly soldered ?
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
Sebo



Joined: Apr 27, 2007
Posts: 525
Location: Argentina

PostPosted: Sun Jan 16, 2011 3:26 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Yves:
All the grounds are OK.
I tried different signals, VCOs (10Vpp), Noise, with various settings of the input attenuator,
all with the same result.
Also is very strange that with the resonance pot at 0, there is no bleeding,
if I increase the resonace the bleeding fades in, reaching maximum level when
reso pot is at 1. If I keep increasing the resonance, the bleeding don't increase, just stay at the same level, until I reach 9 on the reso pot, then the
bleeding fades out, and at 10 there is no bleeding anymore.
The bleeding is really minimal, using my PC Oscilloscope I calculated that
feeding a 10Vpp signal the bleeding is about 60mV, but is perfectly audible.
Also tried different signal of various frequencies and white noise, and I hear the same.
Could be that some of the input signal get to the output trough R43?
Thanks.

_________________
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: 1214
Location: France

PostPosted: Sun Jan 16, 2011 3:35 pm    Post subject: Reply with quote  Mark this post and the followings unread

Sebo wrote:
Could be that some of the input signal get to the output trough R43?
Thanks.

Yes that's likely.
If you wish to have the genuine ARP sound just remove R43. Otherwise a
possible cure would be to send the resonance feedback loop on the input buffer AOP but on the non-inverting pin (but this requires to cut the track from this pin to the ground plane and add a resistor between he pin and ground. I will try this and let you know.

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



Joined: May 04, 2009
Posts: 20
Location: Orlando, Fl

PostPosted: Mon Jan 17, 2011 5:52 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi, my recently built Arp VCF has a DC offset at the output of about 3V. Otherwise, at a quick glance, it looks like it works correctly. On the TL074 input pins 5 and 6 have no DC but output pin 7 has the 3V. Removing the chip removes the DC but replacing it with another TL074 brings it back. The chip is getting a good supply of +/- 15V. I'm guessing the chip must be the issue. It's an STMicroElectronics TL074CN. Any ideas? Am I wrong? I'm stumped. Thanks.
Oh, and thanks for the circuit details. Smile
Back to top
View user's profile Send private message
yusynth



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

PostPosted: Tue Jan 18, 2011 12:38 am    Post subject: Reply with quote  Mark this post and the followings unread

thefunk wrote:
Hi, my recently built Arp VCF has a DC offset at the output of about 3V. Otherwise, at a quick glance, it looks like it works correctly. On the TL074 input pins 5 and 6 have no DC but output pin 7 has the 3V. Removing the chip removes the DC but replacing it with another TL074 brings it back. The chip is getting a good supply of +/- 15V. I'm guessing the chip must be the issue. It's an STMicroElectronics TL074CN. Any ideas? Am I wrong? I'm stumped. Thanks.
Oh, and thanks for the circuit details. Smile


If there is DC offset at the output, there could be three reasons : the first one as you stated is a faulty TL074; the second one is a solder bridge somewhere;
the third is a faulty C10

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



Joined: May 04, 2009
Posts: 20
Location: Orlando, Fl

PostPosted: Tue Jan 18, 2011 11:07 pm    Post subject: Reply with quote  Mark this post and the followings unread

Well, I swapped out the 3 caps around the tl074 and I'm down to .5V. Getting better. But, with no voltage after the 2 22uF caps, my only guess is the .1uf bypass cap on the chip? There is something I'm not yet understanding, though, I'll keep at it. Thanks for the suggestion.
Back to top
View user's profile Send private message
yusynth



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

PostPosted: Wed Jan 19, 2011 7:33 am    Post subject: Reply with quote  Mark this post and the followings unread

I doubt the 0.1µ cap of the TL074 be the main reason. Since the offset dropped from 3V to 0.5V when changing the 22µF tends to confirm that one of them was dead.
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
thefunk



Joined: May 04, 2009
Posts: 20
Location: Orlando, Fl

PostPosted: Wed Jan 19, 2011 10:17 pm    Post subject: Reply with quote  Mark this post and the followings unread

You were right. The cap on the input to the last stage was causing problems. I had to rummage through a number of caps to find one that didn't. Funnily enough, both bipolar caps I removed measure 22uF on my reader. It's now working properly. Though, the output is inverted.

Oh, C10 and R40 are reversed on the schematic from the pcb as the cap is on pin 6.
Back to top
View user's profile Send private message
yusynth



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

PostPosted: Thu Jan 20, 2011 12:49 am    Post subject: Reply with quote  Mark this post and the followings unread

thefunk wrote:
You were right. The cap on the input to the last stage was causing problems. I had to rummage through a number of caps to find one that didn't. Funnily enough, both bipolar caps I removed measure 22uF on my reader. It's now working properly. Though, the output is inverted.

Oh, C10 and R40 are reversed on the schematic from the pcb as the cap is on pin 6.


Yes a capacitor is not only characterized by its capacitance but by other parameters (ESR, DF : Equivalent series resistance, dissipation factor). Because of that the measure of the capacitance is not sufficient to qualify a faulty capacitor. I came accross the same case as yours of a capacitor showing a good capacitance but not behaving in circuits (in particular tantalum capacitor).

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



Joined: Feb 19, 2013
Posts: 14
Location: paris

PostPosted: Fri May 10, 2013 3:59 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi,
i'm soldering my kit and concerning those 2SA798 i have a question.
i don't know how to read the label on the transistor in my kit
4 says : A798 58G
1 say : A798 31G
1 say : A798 5YG

dunno if that matters or if they'r all the same ?

_________________
arp vcf 4072 in progress

Last edited by sylvainmoreau on Sat May 11, 2013 3:06 am; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
yusynth



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

PostPosted: Sat May 11, 2013 12:03 am    Post subject: Reply with quote  Mark this post and the followings unread

THey are all 2SA798 and can be swapped with no problem, the only advice I can give you is to use the 4 A798 58G for Q2,Q3,Q4 and Q5 and use the two others for Q1 and Q6.
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
sylvainmoreau



Joined: Feb 19, 2013
Posts: 14
Location: paris

PostPosted: Sat May 11, 2013 2:40 am    Post subject: Reply with quote  Mark this post and the followings unread

great ! thx
_________________
arp vcf 4072 in progress
Back to top
View user's profile Send private message Visit poster's website
sylvainmoreau



Joined: Feb 19, 2013
Posts: 14
Location: paris

PostPosted: Sat May 11, 2013 4:20 pm    Post subject: Reply with quote  Mark this post and the followings unread

ok i finished my kit and before doing the calibration (i must buy a power supply) i pluged it in my modular.
looks like all is fine "except" the filter that doesn't work Very Happy
it sounds fully open.
dam i'm a bit worried i guess calibration is not the only issue here.

_________________
arp vcf 4072 in progress
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic Moderators: Scott Stites
Page 3 of 4 [86 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2, 3, 4 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
emSynth

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