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
Steiner VCF (TL071/2N3904) troubleshoot (FIXED!)
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 2 [29 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
drakfluga



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Wed May 09, 2012 5:14 pm    Post subject: Steiner VCF (TL071/2N3904) troubleshoot (FIXED!) Reply with quote  Mark this post and the followings unread

Hey,
This is my first post here so forgive my noobishness and all.

I'm having an issue with my YuSynth Steiner VCF build and I'd love some input. The version I'm building uses a TL071 and a pair of 2N3904 trannies.
I get no output in LP or BP, very slight signal in HP and the full signal in AP mode. Gain control works fine. Resonance only very slightly increases gain, by a dB or two. Cutoff does nothing. I've double-checked resistor values and diodes, replaced the transistors a few times etc but no dice. Checked connections to pots and jacks, seems fine. I _think_ I have the pinout of the trannies right. At least it looks right according to the manu datasheet.

Then I noticed that just when I power up, I get a signal through and turning the cutoff actually does seem to work, but the signal gradually disappears. It's like a cap gets charged and then discharges over a few seconds. Turning the power off and on again brings it back for a few seconds, then it's gone again. It's not resonating at all though.

Any ideas? I'm fairly new at this, so I suppose you can flame me for being an idiot if you like. Razz

Last edited by drakfluga on Thu May 10, 2012 3:29 pm; edited 1 time in total
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1221
Location: France

PostPosted: Thu May 10, 2012 4:34 am    Post subject: Reply with quote  Mark this post and the followings unread

Did you clean the solder flux (the brown resin deposit after soldering). In this circuit it is very important to clean it (with alcohol for example) because it may create a parasitic resistance in some part of the circuit which of high impedance.

Otherwise if this does not solve the problem post good resolution photos of your PCB (component and track side).

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



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Thu May 10, 2012 11:54 am    Post subject: Reply with quote  Mark this post and the followings unread

Hey! Is this Mr. YuSynth himself? First I want to say thanks for putting all this material out there! I just found out today that you're the designer of the Arturia Minibrute? It was love at first sight, can't wait to get my hands on one! When I found the schems for the Steiner filter I immediately knew that's the module I wanted to try first since that's what's in the Minibrute. Wink

As for your suggestions, I did clean the board as well as I could to get rid of flux. I've also checked for continuity across all connections except the plastic caps, I can't get the probe to the lead, so I'm thinking I'll just resolder them.

I'm posting images, I want to warn sensitive viewers that my soldering skills are pretty horrible. I am improving though, so hopefully the next board won't look so sloppy. I had to put a few small wire links in where I managed to scrape off bits of track, but I've checked those places and they conduct well enough I think.

Unless there's something wrong with the positioning of the parts, I feel I might just try and etch a new board and try again. It might just be a bad joint I've missed, and I could use the practice anyway. Wink

Posted Image, might have been reduced in size. Click Image to view fullscreen.
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1221
Location: France

PostPosted: Thu May 10, 2012 12:37 pm    Post subject: Reply with quote  Mark this post and the followings unread

Yes this is me yusynth.

OK concerning the PCB I think that although it is quite hard to see the pins of the two trannies from above but I think that they are not connected correctly, in 2N3904, the emitter is the lowest pin when seen from above and with the flat side facing right (same orientation as on your photo) therefore your trannies are reversed connected.

A second issue is the poor quality of the solders. Which type of solder did you use ? The solders appear greyish and dull while they should appear shinny and silvery.

By the way if you are patient, next summer I will publish new modules on my site based on some of the circuits I designed for the minibrute (filter, metalizer...).

_________________
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: Thu May 10, 2012 12:49 pm    Post subject: Reply with quote  Mark this post and the followings unread

It also looks like the trace off pin 8 on the TL72 might be cut after the resistor. That might explain the cutoff?
Back to top
View user's profile Send private message
drakfluga



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Thu May 10, 2012 12:50 pm    Post subject: Reply with quote  Mark this post and the followings unread

Again, forgive my ignorance. I hope I'm not coming off as a complete jerk. The type of solder I use is the type I bought at my local hardware store which they said was "for electronics". It's a 0.8mm "No Clean" wire solder with flux core. I don't know any more than that. What type of solder would you recommend?

Here's a link to the datasheet for the trannies, from the store where I bought them. The pinout according to that sheet is reversed with respect to what you said, but it might of course be wrong. I'll try to reverse them and see if that does anything.

https://www1.elfa.se/data1/wwwroot/assets/datasheets/lz2N3904_e.pdf

Of course I'm patient! Hopefully by that time I will be a bit more experienced too and can handle building the new modules when you publish. Wink

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



Joined: Nov 24, 2005
Posts: 1221
Location: France

PostPosted: Thu May 10, 2012 1:00 pm    Post subject: Reply with quote  Mark this post and the followings unread

THe problem with such projection on a datasheet is that it depends on which projection rule was used (american and european which are of course not the same).

On some other data sheet one can find a true 3D view which does not suffer from any ambiguity like in the following : http://www.datasheetcatalog.org/datasheet/fairchild/2N3904.pdf

Concerning the solder I recommend that you use 60% tin 40% Lead ( this non-RoHS and may be hard to find in Germany nowadays cause it's not "Grün" )


2N3904.jpg
 Description:
2N3904 pinout
 Filesize:  22.07 KB
 Viewed:  4600 Time(s)

2N3904.jpg



Last edited by yusynth on Thu May 10, 2012 1:03 pm; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
drakfluga



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Thu May 10, 2012 1:02 pm    Post subject: Reply with quote  Mark this post and the followings unread

Christ! I see what you mean! I assumed the pins were pointing "toward me". I didn't even consider the ambiguity there.
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1221
Location: France

PostPosted: Thu May 10, 2012 1:09 pm    Post subject: Reply with quote  Mark this post and the followings unread

thefunk wrote:
It also looks like the trace off pin 8 on the TL72 might be cut after the resistor. That might explain the cutoff?


You're right it looks like a cut here.

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



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Thu May 10, 2012 1:22 pm    Post subject: Reply with quote  Mark this post and the followings unread

IT WORKS!

I reversed the trannies and presto!

The "cut" you saw is probably just a shadow in the photo because of the sloppy soldering.

Thank you so much! I've got parts for one more filter, so I'm going to get started building that one soon, and then I'll get an ADSR going too. Smile

It sounds awesome! Tweaking with the trimpot right now trying to get a good range. Would it be possible to switch out the cutoff pot to get a "broader" range? As it is right now it's active range is pretty narrow so to make small adjustments is almost impossible.
Back to top
View user's profile Send private message
drakfluga



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Thu May 10, 2012 3:08 pm    Post subject: Reply with quote  Mark this post and the followings unread

yusynth wrote:

Concerning the solder I recommend that you use 60% tin 40% Lead ( this non-RoHS and may be hard to find in Germany nowadays cause it's not "Grün" )


I think Sweden has the same problem. I'll see if I can track some of that stuff down. Thanks for the tip!
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 1473
Location: Chicago
Audio files: 14

PostPosted: Thu May 10, 2012 5:20 pm    Post subject: Reply with quote  Mark this post and the followings unread

I've seen a lot of recommendation to use the leaded solder...I do understand it flows better, but 1) fumes are big problem for me, much more so with the leaded solder (feel free to explain to my wife why I need an exhaust fan in my office Wink ) and 2) I really don't want leaded anything around my cats & kids.

Part of the fumes issue as well is that my eyesight is bad and trying to use a magnifying glass just screws up my perspective something awful, and I end up burning all kinds of unintended things.

What are the other benefits of leaded solder, if any?
Back to top
View user's profile Send private message
marfoski



Joined: Jan 26, 2011
Posts: 25
Location: Italy

PostPosted: Thu May 10, 2012 11:41 pm    Post subject: Reply with quote  Mark this post and the followings unread

elmegil wrote:
What are the other benefits of leaded solder, if any?


Lower melting point. It's a pain to cope with lead free solder for home work with the usual soldering irons. In Italy the 60/40 it's still common but I buy it in large spools in Asia.
Back to top
View user's profile Send private message
prgdeltablues



Joined: Sep 25, 2006
Posts: 174
Location: UK
Audio files: 11

PostPosted: Fri May 11, 2012 2:13 am    Post subject: Reply with quote  Mark this post and the followings unread

Some useful info here: http://www.societyofrobots.com/robotforum/forums.html?topic=5306.0

on hazards from soldering. The consensus appears to be that the risks posed by fumes arise from the chemical composition of the flux, not from the metal of the solder - ie there's essentially no lead in the fumes. Lead-free solder needs higher temperatures so the flux fumes may in fact be more hazardous. It's the handling of lead-tin solder that has potential health risks, but good hygiene practice - wash your hands after soldering, don't eat or drink when working, should mitigate that.

Peter
Back to top
View user's profile Send private message
drakfluga



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Fri May 11, 2012 1:46 pm    Post subject: Reply with quote  Mark this post and the followings unread

prgdeltablues wrote:
Some useful info here: http://www.societyofrobots.com/robotforum/forums.html?topic=5306.0

on hazards from soldering. The consensus appears to be that the risks posed by fumes arise from the chemical composition of the flux, not from the metal of the solder - ie there's essentially no lead in the fumes. Lead-free solder needs higher temperatures so the flux fumes may in fact be more hazardous. It's the handling of lead-tin solder that has potential health risks, but good hygiene practice - wash your hands after soldering, don't eat or drink when working, should mitigate that.

Peter


This has been my understanding as well. For the metal to get into the fumes you need to hit the boiling point, which is far higher than the melting point, and you definitely shouldn't be soldering at those temperatures.
Back to top
View user's profile Send private message
drakfluga



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Fri May 11, 2012 5:10 pm    Post subject: Reply with quote  Mark this post and the followings unread

Actually, a follow-up question: now that I've got this thing running I'd love to put it on a panel and stick it in a cabinet. For that I need knobs. I've spied some fancy-looking ones at musikding.de, specifically this:
http://www.musikding.de/Knobs/Knobs-Plastics/Metal/Black-Fluted-Silver-Center-27mm::128.html

And this:
http://www.musikding.de/Knobs/Knobs-Plastics/Metal/Black-Fluted-Silver-Center-33mm::935.html

My question: are these the right size to go with the provided panel design? That is, 27 mm for the "normal" size knobs and 33 mm for the cutoff knob? It looks right according to my ruler, but I just want to make sure before I order a ton of the wrong ones. I figured I might as well order enough knobs for a few more modules since I know I'm going to build some more eventually.
Back to top
View user's profile Send private message
yusynth



Joined: Nov 24, 2005
Posts: 1221
Location: France

PostPosted: Sat May 12, 2012 12:09 am    Post subject: Reply with quote  Mark this post and the followings unread

Yes these will do alright (you may go for these), although the design of the panel was done bearing in mind more classical (but more expensive) Moog alike knobs such as :

For the standard knobs
http://www.musikding.de/Knobs/Knobs-Plastics/Metal/Black-Fluted-Silver-Center-26mm-white-dots::1716.html
unfortunately Musikding does not provide the bigger 33 mm in this style

For the pointer knobs
http://www.musikding.de/Knobs/Chickenhead-knobs/Chickenhead-special/Chickenhead-round::3049.html

Otherwise Ben at Bigbluewave provides the full set :
http://www.bigbluewave.co.uk/resynthesis/yusynth_front_panels.htm#Classic%20Style%20Knobs

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



Joined: May 09, 2012
Posts: 17
Location: Gothenburg SE

PostPosted: Mon May 14, 2012 4:35 pm    Post subject: Reply with quote  Mark this post and the followings unread

Bit of an update if you're interested: I got some 60/40 solder and soldered my second PCB tonight; the ADSR. Such an improvement! I'm going to etch a new PCB and resolder the filter now. I'm never using that horrible lead-free stuff again! Smile
Back to top
View user's profile Send private message
tazer



Joined: Oct 18, 2010
Posts: 49
Location: UK

PostPosted: Wed May 16, 2012 8:41 am    Post subject: Reply with quote  Mark this post and the followings unread

well done you will have no regrets changing from unleaded solder. I have concerns about the fumes from soldering so I always wear a mask when soldering with the leaded solder, I use a mask suitable for air brushing that is very effective. You are best to keep it out of your lung's if possible, heavy metals are very bad for your system they build up as deposits in your body and are hard to shift once in there. I don't know if it the case that there is no lead in the fumes, there is lead in car exhaust fumes so i'm presuming they are probably in solder fumes also, better safe than sorry really especially if you do (or plan to do) alot of soldering.
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 1473
Location: Chicago
Audio files: 14

PostPosted: Wed May 16, 2012 8:44 am    Post subject: Reply with quote  Mark this post and the followings unread

I've had this discussion elsewhere and been assured that if you're soldering correctly there is no way to get the lead hot enough to boil/become airborne. A car engine operates much hotter than my iron Smile. The worst of it is the fumes from the rosin flux.
Back to top
View user's profile Send private message
tazer



Joined: Oct 18, 2010
Posts: 49
Location: UK

PostPosted: Wed May 16, 2012 1:43 pm    Post subject: Reply with quote  Mark this post and the followings unread

assured by someone or not i'm sure there is still harmful by product from heating lead/tin/flux and breathing it (also getting it on fingers). I'm just telling someone that is starting out to take care like we all should if we wanna be doing our trade for many years without adverse affect. There was a guy over on the circuit benders forum had basically to stop electronics because he became ill and after tests he had crazy levels of lead and all these lovely chemicals that you find in circuit boards (the circuit benders to like their fingers in their mouths to wet em and stick em on the board to short circuit it.) I've had this discussion also on forums and some folk are very blase about the fact they are actually dealing with harmful chemicals and heavy metals.
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 1473
Location: Chicago
Audio files: 14

PostPosted: Wed May 16, 2012 1:45 pm    Post subject: Reply with quote  Mark this post and the followings unread

oh yeah, I meant that the flux itself is the thing to worry about, and plenty too. Just that the lead itself is not the main concern unless you're sticking it in your mouth....
Back to top
View user's profile Send private message
tazer



Joined: Oct 18, 2010
Posts: 49
Location: UK

PostPosted: Wed May 16, 2012 2:04 pm    Post subject: Reply with quote  Mark this post and the followings unread

read this


lead.pdf
 Description:

Download
 Filename:  lead.pdf
 Filesize:  55.4 KB
 Downloaded:  218 Time(s)

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



Joined: Mar 20, 2012
Posts: 1473
Location: Chicago
Audio files: 14

PostPosted: Wed May 16, 2012 2:11 pm    Post subject: Reply with quote  Mark this post and the followings unread

I don't understand why you seem to think I'm being blase or arguing against you in any sense. You're not going to inhale molten/boiled lead while soldering (scientifically impossible unless you're doing something very wrong), but there are plenty of other avenues for lead and you will inhale lots of other nasties from the flux. Everyone should take good precautions.
Back to top
View user's profile Send private message
tazer



Joined: Oct 18, 2010
Posts: 49
Location: UK

PostPosted: Wed May 16, 2012 2:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

I didn't say you were being blase (I said some people are), or trying to argue i'm just pointing out this stuff is dangerous. You think there is no danger to inhale fumes from molten lead I do that is a difference of opinion not an arguement, i've put up some information for others to read so they may be aware of the dangers and make up their own minds. We all on this forum basically want the same thing to make circuits and have fun make music, you need to be healthy to do this and I think we are both agreed on this, don't wanna bend anyone's ear about it..
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 [29 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