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
Buchla 266 SoU -- Eurorack!
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 2 of 2 [28 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
Author Message
masterofstuff124



Joined: Sep 21, 2015
Posts: 23
Location: Miami, Florida

PostPosted: Fri Dec 30, 2016 4:03 pm    Post subject: Reply with quote  Mark this post and the followings unread

looking through all of the yearly build threads, all of AlanP adaptations and designs look amazing. I want all of them!

208 random
Quadrature function Generator
Source of uncertainty Dunno!


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



Joined: Mar 20, 2012
Posts: 2052
Location: Chicago
Audio files: 16

PostPosted: Wed Apr 18, 2018 7:03 pm    Post subject: Reply with quote  Mark this post and the followings unread

Gotten around to building this, and I wanted to pop in and make a note.

Because of the 5V supply, the eDruid noise chip requires a change to either R176 or R174. Otherwise the level is wrong, and the FRV doesn't do as much as it should. Got this from Dave Brown's build of Roman F's clone of the SOU.

Dave's solution was to replace the 39K R174 (it was different designator on that schematic, but same positionally in the circuit) with a 6.8K resistor.

In my opinion this messes up the passive LPF consisting of R174 and C56. My preferred solution is to replace R176 (a 10K) with a 56K. The whole thing being that there's a voltage divider there, and since the voltage is significantly lower out of the replacement noise chip, you have to adjust it to get the same levels into the next stage of the circuit.

See Dave's notes and modifications for the Roman F version on this page:

https://modularsynthesis.com/roman/buchla266/266sou_pcb2.htm

If you look through his notes on the SOU, he's made some other changes from Roman's version, I haven't gone through and made those changes myself; I'll have to see whether I think they're necessary after I'm done with the build, but I know this particular one definitely is needed.
Back to top
View user's profile Send private message
AlanP



Joined: Mar 11, 2014
Posts: 519
Location: New Zealand
Audio files: 31

PostPosted: Fri May 11, 2018 4:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

It's been awhile since I did the PCBs, but IIRC, I included a lot of Dave's mods (including protection diodes.)
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 2 of 2 [28 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2
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