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
  Jez Adventures in Sound
Please visit the chat
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
Chime Sim build issues
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [14 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
whomper



Joined: Dec 15, 2007
Posts: 200
Location: Israel
Audio files: 2

PostPosted: Tue Nov 04, 2008 2:59 pm    Post subject: Chime Sim build issues Reply with quote  Mark this post and the followings unread

Hi,


Testing the chime, I stumbled into a strange problem. The trigger is not getting through and operating the module. I can tune the noise coming out of the module using the 3 trimpots and silence the constant tone, but after that, nothing happens.

Further, I measure -15V on pin 1 of IC1, which afaik is not right.

Any clues?

_________________
Erez Yaary

Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1174
Location: australia
Audio files: 4

PostPosted: Tue Nov 04, 2008 3:51 pm    Post subject: Re: Chime Sim build issues Reply with quote  Mark this post and the followings unread

whomper wrote:
Hi,
Further, I measure -15V on pin 1 of IC1, which afaik is not right.

Any clues?

All sections of IC1 and IC2 are set up as comparators (note the lack of feedback circuitry) meaning the outputs will either be +15V or -15V.
So IC1 pins 1&7 you should measure approx -15V, with nothing on the input.
IC2 pins 1&7 should be +15V, with nothing on the input.

You should be able to see IC1 pin1 or pin 7 go to +15V when you have a +3V signal on the appropriate input.

Assuming your LM358s are okay, maybe -
In his notes section, Ken mentions you made need to increase the value of a resistor that is part of the input section -
'If you find the damper kicks in too soon, replace the 100k on pin 5 of IC2B with something higher, e.g. 220 or 330k. '
Back to top
View user's profile Send private message Visit poster's website
whomper



Joined: Dec 15, 2007
Posts: 200
Location: Israel
Audio files: 2

PostPosted: Wed Nov 05, 2008 4:10 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi,

Thanks for the tips.
Did some basic testing; I could not get 15V at IC1 1&7, only 1.4V. Might be because of the voltage divider before it?
Input voltage above 3V does not influence the constant -15V at IC1 pin1.

Will try to play a little more with that and implement a change to 330K as Ken suggested.

_________________
Erez Yaary

Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1174
Location: australia
Audio files: 4

PostPosted: Thu Nov 06, 2008 7:57 am    Post subject: Reply with quote  Mark this post and the followings unread

I should have said 3V (or more) trigger signal, the outputs of IC1 will only pulse high briefly as the input signal changes. The 10n caps on the input circuit block any DC, if you just apply 3V DC to the inputs nothing will happen.
1.4V might be all the multimeter can detect before the signal goes low again.

Do you detect the 1.4V just briefly and then it is back to -15V? That may mean it is okay. If it is a constant 1.4V, maybe not so okay.

Just checking, it is an LM358?
Back to top
View user's profile Send private message Visit poster's website
whomper



Joined: Dec 15, 2007
Posts: 200
Location: Israel
Audio files: 2

PostPosted: Fri Nov 07, 2008 4:45 am    Post subject: Reply with quote  Mark this post and the followings unread

Yeah, I am feeding it a pulse/tri LFO that reaches above 4V.

Pin1 of IC2 is constant at 1.4V, and the input signal does not change it.

I am using TL072. With LM358, pin1 of IC2 is at 0V (might be a defective IC..)

I am out of ideas and am starting to give up on this module...

_________________
Erez Yaary

Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1174
Location: australia
Audio files: 4

PostPosted: Fri Nov 07, 2008 7:26 am    Post subject: Reply with quote  Mark this post and the followings unread

whomper wrote:


I am using TL072. With LM358, pin1 of IC2 is at 0V (might be a defective IC..)

I am out of ideas and am starting to give up on this module...


Maybe a TL072 will give you trouble as IC1 or IC2. This was explained to me when I had similar problems. The TL series don't really like being used as comparators, when the output swings from one extreme to the other they can get stuck (latch) and don't reset 'til the power is turned off.

A TL072 cannot get much closer than ~1V to each power rail, which might be why you are reading 1.4V on pin1. It is trying to get to 0V but cannot . The LM358 can go from rail to rail, 0-15V.

Have you checked the power pins?

IC1 should have +15V on pin8 , -15V on pin 4. Should also have ~2V on pins 2&6.

IC2 should have +15V on pin8, 0V on pin4 and ~1.4V on pins 5&3. The outputs of IC2 should swing from 0V to +15V.

Don't give up, the night is always darkest just before dawn Smile
its been about 5 years since I built this cct, don't remember having any trouble with it. Sorry if my help isn't helping much, the ccts I know best are the ones I made mistakes with, a good way to learn is by stuffing up......though it's better to learn from other people's stuff-ups.
Back to top
View user's profile Send private message Visit poster's website
whomper



Joined: Dec 15, 2007
Posts: 200
Location: Israel
Audio files: 2

PostPosted: Fri Nov 07, 2008 12:39 pm    Post subject: Reply with quote  Mark this post and the followings unread

Thanks andrewF for all your time and help so far, including the warm encouraging words!

I'll buy a couple of fresh LM358 to eliminate faulty IC and run a clean test.

Will post results.

_________________
Erez Yaary

Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de
Back to top
View user's profile Send private message
whomper



Joined: Dec 15, 2007
Posts: 200
Location: Israel
Audio files: 2

PostPosted: Mon Nov 10, 2008 3:03 pm    Post subject: Reply with quote  Mark this post and the followings unread

Ok, placed new set of LM358.

Now it seems like the trigger phase works correctly as I can measure the right voltages across IC1 and IC2.

Next problem to solve; Why do I get a constant sound with no envelope and damping?

Strange thing, when I connect the + lead of a multimeter (or my body with a screwdriver) to IC2 PIN6 (or 547 pin 2), suddenly I am getting a short bell sound synced to the trigger (which goes to say the trigger is ok) and as soon as I disconnect the test lead, I can hear 2-3 more short bell sounds and then constant tone again.

I am not sure what to make of it. I have tried to change the 100K resistor to 330K and also to 33K but nothing changed.

_________________
Erez Yaary

Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1174
Location: australia
Audio files: 4

PostPosted: Tue Nov 11, 2008 3:01 pm    Post subject: Reply with quote  Mark this post and the followings unread

Sounds like you are almost there, have trigger, oscillation....just the envelopes to go Smile

Do both chimes on the PCB exhibit the same behaviour?

what transistors are you using, BC547 or a substitute?

Are you using 2 or 3 oscillators per chime?
Back to top
View user's profile Send private message Visit poster's website
whomper



Joined: Dec 15, 2007
Posts: 200
Location: Israel
Audio files: 2

PostPosted: Sun Nov 16, 2008 1:48 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi,

Well, after letting the module rest a bit in a box, I went back to it to test your comments.

I am using BC547B and all 3 OSC.

When testing the V across pin6 of IC2, I see that it slowly decreases over time after trigger and at the same time pin7 is at 0V. The effect is a constant sound after trigger and a slowly decreased volume until damper kicking in. This looks good.

My only issue now is the envelope. The 2u2 discharges too slow and it seems like the 100K pot makes no difference on the rate of decrease.
It seems like the envelope there is still not working correctly.

What are the components involved in the envelope? I see 1N4148, 2u2, 10K and 100K pot. Is the bc547 also part of the game?

_________________
Erez Yaary

Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1174
Location: australia
Audio files: 4

PostPosted: Sun Nov 16, 2008 2:31 am    Post subject: Reply with quote  Mark this post and the followings unread

yes bc547 is a part of the EG, in the sense that it buffers the EG voltage, but it shouldn't have any effect on the decay time.

The 2u2 cap gets charged up, and it wants to unload. The Bc547 base and IC2, pin6 pass very little current (ideally 0), so the only place for the 2u2 cap to unload is thru the 10k resistor and 100k pot and into ground.
So you have a max value of 110k Ohm and a min value of 10K Ohm, depending how the pot is set. The higher the resistance, the slower the decay.

Maybe check with a multimeter, the resistance between the 2u2 cap/10k Ohm resistor node and ground (circuit turned off). Turning your decay pot should see the 10k-110k range. If you are seeing a much higher reading it might be the cause of the too slow decay.
Back to top
View user's profile Send private message Visit poster's website
whomper



Joined: Dec 15, 2007
Posts: 200
Location: Israel
Audio files: 2

PostPosted: Sun Nov 16, 2008 4:49 am    Post subject: Reply with quote  Mark this post and the followings unread

ok, problem solved. Very Happy

The root cause lies with the fact that on the silkscreen, pot1 and pot2 are switched. Shocked

As I was testing the board, I tested one path at a time and connecting only those parts, and as such the pot was always connected to the other path, leaving the path I was testing open. This is why I saw a long decay.

All is well now.

Thanks andrewF for your many ideas and comments, it allowed me to hang in there while I debugged.

_________________
Erez Yaary

Home Page: http://www.yaary.com
Buy my CDs at http://www.mellowjet.de
Back to top
View user's profile Send private message
andrewF



Joined: Dec 29, 2006
Posts: 1174
Location: australia
Audio files: 4

PostPosted: Sun Nov 16, 2008 5:37 am    Post subject: Reply with quote  Mark this post and the followings unread

Very Happy cool!
Back to top
View user's profile Send private message Visit poster's website
e-grad



Joined: Sep 12, 2008
Posts: 142
Location: Berlin

PostPosted: Sun Apr 14, 2013 2:28 am    Post subject: Reply with quote  Mark this post and the followings unread

whomper wrote:
The root cause lies with the fact that on the silkscreen, pot1 and pot2 are switched.


That solved my problem, too!

However, the output is rather quite. I think I'll increase the value of the resistor in the feedback loop at the output.
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 1 [14 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Ken Stone designs - CGS
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