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 » Developers' Corner
Frequency Central FC-Power mod
Post new topic   Reply to topic Moderators: DrJustice
Page 1 of 1 [1 Post]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
ixtern



Joined: Jun 25, 2018
Posts: 145
Location: Poland

PostPosted: Wed Oct 30, 2019 5:55 am    Post subject: Frequency Central FC-Power mod
Subject description: Modding FC +-12V power module
Reply with quote  Mark this post and the followings unread

Original Frequency Central FC-Power module works with single 12V AC supply. It has two half-wave rectifiers. Maximum current is about 0.5-0.7A (depends on heat in regulators to dissipate).

I am used to double 12V AC transformers, which needs full-wave rectifier (bridge) but benefits in lower current needed from trafo and lower ripples, so I've modded this module a little.

Main changes:

1. Full-wave rectifier added. 2A diodes used instead of 1A. AC input connector added. All on additional mini-board soldered to the AC input of the module. Original rectifying diodes were removed. Needed additional connections were made by isolated wires.

2. 78S12 (2A max output current ) regulator was used instead of regular 7812. +12V line usually needs more current than -12V.

3. Bigger, black radiators were used to disspate more power. Some mechanical elements were added to hold them in place. As they were mounted by sides, whole module width is now twice the original.

4. Rectifier's capacitors (4700 uF) for 35V were used instead of 25V, as I've found them with the same diameter. There may be little higher
but it doesn't matter.

Module can provide +12V/1.2A and -12V/0.9A which was tested under load. 78S12 and 7912 temperature raised to 50 Celsius deg (at 25 Celsius deg ambient),. I think it's the maximum safe output power for a long time load, with such a small radiators.
The interesting thing is that lost (radiated) power was almost constant for the output current within 0.6-1.2A. It was due to a diminishing AC voltage from transformer under load. DC input voltage under 1.2A load was 15V, with no load was over 17V.
Trafo used was EI 66/23 212 from Reichelt (36W/2x12V).

Measured +12V ripples under 1.2A load were 10mV p-p.


IMG_20191030_121522.jpg
 Description:
Modded power module in eurorack frame.
 Filesize:  3.28 MB
 Viewed:  291 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

IMG_20191030_121522.jpg



FC-Power_mod.png
 Description:
Schematic of modded power module.
 Filesize:  34.8 KB
 Viewed:  322 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

FC-Power_mod.png


Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: DrJustice
Page 1 of 1 [1 Post]
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 » Developers' Corner
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