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
  EdisonRex Edison's Electronic Review
Please visit the chat
 Forum index » DIY Hardware and Software
M A Ruberto Synthacon VCF with Turbo switch
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [3 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
elmegil



Joined: Mar 20, 2012
Posts: 1447
Location: Chicago
Audio files: 14

PostPosted: Sat Feb 23, 2013 6:58 am    Post subject: M A Ruberto Synthacon VCF with Turbo switch Reply with quote  Mark this post and the followings unread

I bought an M A Ruberto Synthacon VCF PCB for which we have a parts list, but no schematic or wiring diagram. I've done some googling and found that M A Ruberto is also Somnium 7, and this PCB was discussed on the Synth DIY list back in 2007, but any links to anything like schematics are dead and not recoverable with web.archive.org. Nothing here or on Muff's of much help either.

Lest anyone take it wrong, this is not a complaint, it was a good price Smile

But I'm trying to cast about and see if anyone has any additional information about this PCB. Unfortunately my attempts to email the Synth DIY list itself (I am a member for some time) don't appear to be going through, for reasons unknown. I've emailed the list owner, but no reply to figure it out so far. I've also attempted to contact Mr Ruberto through Somnium 7's soundcloud page, but again, no reply so far.

I've started mapping out the circuit in Eagle so I can compare to other Synthacon VCF schematics, but it's slow going, of course.

Any information is welcome Smile
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 1447
Location: Chicago
Audio files: 14

PostPosted: Sat Feb 23, 2013 12:45 pm    Post subject: Reply with quote  Mark this post and the followings unread

Got an answer over on Muff's sharing here for completeness if someone else ends up in this boat Smile

http://www.muffwiggler.com/forum/post-1087618.html#1087618
Back to top
View user's profile Send private message
elmegil



Joined: Mar 20, 2012
Posts: 1447
Location: Chicago
Audio files: 14

PostPosted: Sun Mar 24, 2013 9:44 pm    Post subject: Reply with quote  Mark this post and the followings unread

I finally have this built, and I'm having a couple of issues.

1) I only get sound when I have the turbo switch on. I'm totally not clear on what the FET is supposed to be doing, but that is in fact the only substitution I've made in this circuit--I used a 2N5458 rather than 2N4302 because I had one on hand, and things I read online suggested that was a legitimate sub.

2) The cutoff frequency is really only useful in the last 1/3 of its rotation CCW. For low pass, after that, the rest of the way CW, I'm pretty much passing everything. For high pass I get some pass through up to 50% but after that it's entirely cut off the whole rest of the way around. I hooked the lowpass up to a frequency analyzer, and with the cutoff set fully CCW and the Resonance at about 2/3's (so it wasn't screaming at me), my cutoff appeared to be somewhere between 3 & 4 Kilohertz.

I'm looking at the cutoff setting, and I also looked to compare to the YuSynth Synthacon that is also done with a 2SC1583, and the voltage swing is essentially the opposite--The Ruberto version, per the schematic, ranges from 15V to ~4V, whereas Yves' version ranges from 7.5V to Ground.

I'm considering swapping that 20K resistor to the 15V side rather than the Ground side, to see if that behaves better.


synthacon_vcf_rev5_scm_398.jpg
 Description:
slightly cleaned up from the schematic posted on Muff's
 Filesize:  193.32 KB
 Viewed:  71 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

synthacon_vcf_rev5_scm_398.jpg


Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [3 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
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