electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links
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
Stripboard Synthacon Hum
Post new topic   Reply to topic Moderators: Scott Stites
Page 1 of 1 [8 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
hoyager



Joined: Feb 16, 2010
Posts: 27
Location: New Zealand

PostPosted: Mon Apr 23, 2012 6:24 pm    Post subject: Stripboard Synthacon Hum Reply with quote  Mark this post and the followings unread

Would anyone know if this was a normal level of hum?



Its the yusynth version, with the multiple inputs.

Input amp is set to be hot for overdriving.

Its def coming from the filter, because when the inputs are turned down...

I've wired the grounds to the dc jack, and its being powered by 9v through an LT1054 as bipolar output, putting at -15.5 and +16.2 ish.

All ground points are within 1mv from each other.

I Changed the 680n to a polar 0.1uf which seems to make it a little quieter.

I read about someone putting a trimpot at the junction of both the 2.2k's and the 1k coming from the positive supply. Would this help eliminate the hum?

Could it be the layout is too tight and the bits are just too close to each other?

Andy


Steiner Synthacon Yusynth.png
 Description:
 Filesize:  177.75 KB
 Viewed:  705 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Steiner Synthacon Yusynth.png


Back to top
View user's profile Send private message
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Mon Apr 23, 2012 6:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

My gut reaction is the PSU. Maybe deriving the +15v/-15v rails from a +9v rail is just too noisy?
Try running it temporarily on 2 * 9V batteries, and see what the hum level does.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
hoyager



Joined: Feb 16, 2010
Posts: 27
Location: New Zealand

PostPosted: Mon Apr 23, 2012 6:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

Ok thanks

I've used the psu with a few MS20 filters though, which when wiring the grounds to the jack seems to eliminate any hum / noise.

There are 100uf's and zeners on the psu rails and 100n's on the board

The circuit feels very live, the diodes don't like being touched and a few of the caps react too. The hum does go away if I touch the res pot, but when its grounded its the same.

R13 and the res pot on yusynths discrete version are 22k, while on the CA3096 version they're both 2.2k. That wouldn't be wrong would it?


Voltage Doubler and Inverter Mod.png
 Description:
 Filesize:  67.08 KB
 Viewed:  585 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

Voltage Doubler and Inverter Mod.png


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



Joined: Feb 16, 2010
Posts: 27
Location: New Zealand

PostPosted: Tue Apr 24, 2012 4:35 am    Post subject: Reply with quote  Mark this post and the followings unread

I though I should add that the transistors aren't matched, am using bc547's.

It definitely works but would matching them ease the hum?

Andy
Back to top
View user's profile Send private message
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Tue Apr 24, 2012 4:42 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm not sure.
If they're part of an exponential converter for 1V/Oct tracking, then I don't think it would make a difference. But if they are somehow inside the VCF, as resonance gates etc, then they might create a hum problem.

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
yusynth



Joined: Nov 24, 2005
Posts: 1314
Location: France

PostPosted: Thu Apr 26, 2012 12:57 am    Post subject: Reply with quote  Mark this post and the followings unread

Hum can come from missing connections to the circuit ground (0V), long un-shielded input and output wires, a poorly filtered PSU (have you tried with batteries as suggested by Uncle Krunkus), capacitance problem between stripboard tracks.
_________________
Yves
Back to top
View user's profile Send private message Visit poster's website
mercury8



Joined: Nov 25, 2018
Posts: 14
Location: grand rapids ohio

PostPosted: Sun Dec 16, 2018 3:22 pm    Post subject: stiener Reply with quote  Mark this post and the followings unread

can this run off of -12 +12 for eurorack???
Back to top
View user's profile Send private message
khakifridge



Joined: Jul 15, 2014
Posts: 27
Location: UK

PostPosted: Mon Dec 17, 2018 2:30 am    Post subject: Reply with quote  Mark this post and the followings unread

Yep. Says so at Yves' webpage.
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 [8 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 » 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


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use