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
DONE PCBs ordered. Yet another Moog 914 clone...
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
LFLab



Joined: Dec 17, 2009
Posts: 192
Location: Rosmalen, Netherlands

PostPosted: Thu Aug 14, 2014 1:23 am    Post subject: Reply with quote  Mark this post and the followings unread

Seek help Very Happy

Serge resonant eq?
Back to top
View user's profile Send private message
dingebre



Joined: Aug 10, 2008
Posts: 263
Location: Salt Lake City, UT USA

PostPosted: Wed Nov 12, 2014 2:12 am    Post subject: Reply with quote  Mark this post and the followings unread

Good news, the GIC and Inductor versions are both finally working. I ordered PCBs today. If anyone is interested in buying a set, email or PM.

GIC - $70.00 per set (A little expensive, but they are 4 layer PCBs to minimize noise and hum)

Inductor - $50.00 per set (Will work with either the large or small core 5 Henry inductors Carsten has made)

A couple of quick comments on construction. I'll put more detail together if people buy the PCBs.

A set consists of 4 PCBs, a top, middle, and bottom PCB adn an I/O PCB which mounts to the bottom filter cell PCB. They have PCB mounted pots, Panasonic EVU-E2JFK4D54, DigiKey P3U0503-ND. You will most likely need to trim the shaft a little depending on the knob you use. the HP and LP pots are not PCB mounted and can be any smallish panel mount pot. I've calculated the values for the capacitors which are on the silkscreen. There are two choices, one for an "exact" cutoff frequency, one that pushes the cutoff either up or down about 6% to mimic what it appears Moog did (as well as Jurgen Haible on his version).

The construction is not bad. The calibration is the problem, here. Ideally, you want the overall "Q" to be about 3.7 (per Yves Usson's testing of an original 914). The trimmers will adjust that, but it's not so straight forward to tell. I've just set my trimmers to point to about 10:00 or 11:00 and the result is very pleasing. you don't want too high a "Q" or you lose some of the harmonics between the cells. Too low and you miss the nice resonance when the input attenuator is fully CW.

Be warned, both versions are kind of pricey to build. For the inductor version, you need a set of Carsten's inductors. for the GIC, you need 29 of the best, lowest noise, op amps you are willing to buy. I ended up using the OPA2227, about 4.50 each for 10-99 pieces. Probably way overkill. Jurgen used an MC4558 at about $0.40 depending on the exact one you pick.

So, enough for now. Please feel free to contact me if you are interested. I've got about 2 weeks til the PCBs are in. In the mean time, I'll work on a BOM and some construction notes.

_________________
David M. Ingebretsen, M.S., M.E.
Collision Forensics & Enginering, Inc.

dingebre@3dphysics.net
http://www.xmission.com/~dingebre/Synthasystem.html
Back to top
View user's profile Send private message
dingebre



Joined: Aug 10, 2008
Posts: 263
Location: Salt Lake City, UT USA

PostPosted: Today, at 12:25 am    Post subject: Reply with quote  Mark this post and the followings unread

If anyone is interested, PCBs have arrived for either the GIC or inductor version. PM or email if interested. See first post for more details.

David


2014-11-21 22.28.57_resize.jpg
 Description:
 Filesize:  297.68 KB
 Viewed:  3 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

2014-11-21 22.28.57_resize.jpg



_________________
David M. Ingebretsen, M.S., M.E.
Collision Forensics & Enginering, Inc.

dingebre@3dphysics.net
http://www.xmission.com/~dingebre/Synthasystem.html
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