Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd January 2008, 12:50 AM   #1
jethdub is offline jethdub  United Kingdom
diyAudio Member
 
Join Date: Jan 2006
Location: Mexico, at present.
Default Parallel Caps for Large Values..

Is there any reason why it would not be sensible to make up higher values for blocking caps by paralleling smaller value caps. Just thinking that in certain cap ranges package size and cost jumps past say the 1uF mark and might be more economical to combine caps, and possibly easier to fit into layouts.
I was also reading something here about paralleling caps of different materials to achieve a particular sound economically, though this was more based on large value caps with a small value high quality (eg poystyrene) bypassing them.
  Reply With Quote
Old 23rd January 2008, 01:04 AM   #2
okapi is offline okapi  United States
diyAudio Member
 
okapi's Avatar
 
Join Date: Aug 2004
Location: Buffalo
using caps in parallel is a reasonable approach.

here is a link that deals with large value caps but i think it applies: esp
  Reply With Quote
Old 24th January 2008, 05:58 PM   #3
Minion is offline Minion  Canada
diyAudio Member
 
Join Date: May 2006
Location: Cowican Bay , vancouver island
Paralelling caps also helps with ESR...
  Reply With Quote
Old 24th January 2008, 07:40 PM   #4
jethdub is offline jethdub  United Kingdom
diyAudio Member
 
Join Date: Jan 2006
Location: Mexico, at present.
Thanks all...
other question then...why don't I see it done very often if there are such obvious benefits..?
  Reply With Quote
Old 24th January 2008, 07:56 PM   #5
Minion is offline Minion  Canada
diyAudio Member
 
Join Date: May 2006
Location: Cowican Bay , vancouver island
I guess mostly because of space...Paralelling Caps takes up more space on a curcuit board than just useing one big cap and it probably costs more to buy say 2 10,000uF caps than it does to buy a 20,000uf Low esr cap.....

I personally Paralell caps quite often just because I don"t have the correct Value(s).....
  Reply With Quote
Old 24th January 2008, 07:59 PM   #6
okapi is offline okapi  United States
diyAudio Member
 
okapi's Avatar
 
Join Date: Aug 2004
Location: Buffalo
i can't speak for others but with some recent powersupplies i put together i did not use multiple caps because of space constraints.

also, the cost of a single panasonic 10 000 micro farad cap is about 10 bucks so any savings is not going to be huge.

nevertheless, for some upcoming projects i do plan on paralleling caps.

the savings might be much larger for exotic caps.
  Reply With Quote
Old 24th January 2008, 10:11 PM   #7
diyAudio Member
 
Rodeodave's Avatar
 
Join Date: Dec 2004
Location: in the alps
Blog Entries: 1
I recently bought 60 (that's right, sixty) Panasonic FC 2200uF 50V for 14 Euros, which equals 10 (ja, that's right, ten) Dollars.

I'll use them in the power supply of the Mini Aleph I'm about to build. The psu will be a CLC type with positive and negative rails. 22000uF of C, 2,2mH of L and 44000uF of C.

So each rail will have ten caps in parallel, one 2.2mH inductor in series and another 20 caps in parallel. The capacitors will be paralleled in bundles of ten (see picture) and each bundle will be grounded separately. In power supplies with many caps I like to use a combination of star-grounding and ground-follows-signal.

Aber Achtung, there might/will be some problems. As the ESR will get lower by paralleling caps (which basically is good), the leakage current will rise (which is bad).
The wires' inductance might also be a problem. See this excellent thread for reference:

http://www.diyaudio.com/forums/showt...002#post548002


Jean Hiraga's "Le Monstre" has loads of capacitors in it's power supply:

http://www.bonavolta.ch/hobby/fr/audio/monster.htm


Why people bypass (parallel) large capacitors with "a small value high quality" cap?
Because the impedance of a capacitor goes down with increasing frequency. So the smaller capacitor, mostly a non-polar film-type, has to compensate for the larger cap's inability to filter/decouple/supply the high-frequency current pulses. A lot of voodoo going on here.

So, to give an example, here's someone's approach to paralleling capacitors I stumbled across recently:

http://galerie.hifi-forum.de/data/media/11/Power.jpg


Alright, that'd be my "seinen Senf dazu geben". Btw, the word "Kondensatorgrab" gives a maximum of 21 hits on goggle, "capacitorgrave" gives zero. Don't know what this means.
Attached Images
File Type: jpg 22k.jpg (97.2 KB, 164 views)
__________________
Gravity - Making the G since 13.7 billion B.C.
  Reply With Quote
Old 24th January 2008, 11:08 PM   #8
diyAudio Member
 
Rodeodave's Avatar
 
Join Date: Dec 2004
Location: in the alps
Blog Entries: 1
Default (nein, that's not right, it's 20)

I confused things. 14 Dollars are ten Euros. So 14 Euros are 20 Dollars, roughly.
__________________
Gravity - Making the G since 13.7 billion B.C.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Bypass caps values advice AndrewGM Solid State 2 27th May 2009 09:48 PM
Large caps Stuart Easson Swap Meet 26 25th March 2009 03:57 AM
Paralleling small value caps with large value PS caps xyrium Power Supplies 16 14th October 2005 04:06 PM
Help with identifying some caps and their values on a phono preamp uniuniunium Parts 62 9th November 2003 04:52 PM
caps and values theChris Parts 0 23rd December 2002 06:32 AM


New To Site? Need Help?

All times are GMT. The time now is 04:41 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2