lots of parallel caps, why? - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 12th January 2004, 03:53 PM   #1
diyAudio Moderator
 
JojoD818's Avatar
 
Join Date: Mar 2003
Location: searching...
Default lots of parallel caps, why?

Hi everyone,

I just listened to a Carver AV-64 and was pleased with it's sound. Looking through the chassis, there seems to be nothing special about the power amp's circuit but I did noticed an array of 1,000uf capacitors, 10 per rail, for a total of 20 pieces.

My question is why use 10 pieces of 1,000uf caps when you can use a single 10,000uf capacitor? Does it have to do with ESR? Or whatever it is called? Any advantage, disadvantage?

Best regards,
JojoD
  Reply With Quote
Old 12th January 2004, 03:57 PM   #2
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
Low ESR and price as far as im concerned. In some cases you can get higher ripple out of a bunch of smaller caps than from one big cap.

MAgura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  Reply With Quote
Old 12th January 2004, 04:02 PM   #3
diyAudio Moderator
 
JojoD818's Avatar
 
Join Date: Mar 2003
Location: searching...
Low ESR = good? High ripple = bad?

Did I get it right?

JojoD
  Reply With Quote
Old 12th January 2004, 04:03 PM   #4
diyAudio Member
 
Join Date: Oct 2002
Location: pittsboro, NC
ESR and cost, possible size constraints also.
There are many threads here on ESR - Effective Series Resistance - and its pluses/minus.
Rod Elliot has a good artcle on it here:
http://sound.westhost.com/power-supp...apacitor-value
go about 2/3 down to:Capacitor Ripple Current
  Reply With Quote
Old 12th January 2004, 04:04 PM   #5
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
Ripple capacity for a cap is the current you can draw from them, naturally limited by the esr as well.

MAgura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  Reply With Quote
Old 12th January 2004, 04:14 PM   #6
KlausB is offline KlausB  Germany
diyAudio Member
 
KlausB's Avatar
 
Join Date: Dec 2003
Location: Dresden
Hi,
besides capacitance, every electrolyte cap has resistance and inductance . Bigger electrolytes tend to have higher inductances, smaller caps lower inductances.

By paralleling similar caps you add the capacitances, while the over all inducance equals cap inductance / number of caps.

So by paralleling 10 caps you only have 1/10 of the inductance.
Also the cap resistance is reduced. Hence the parallel setup may deliver more current faster.

Cheers
KlausB
  Reply With Quote
Old 12th January 2004, 04:21 PM   #7
Account Disabled
 
Join Date: Apr 2003
Location: US
Quote:
Originally posted by KlausB
So by paralleling 10 caps you only have 1/10 of the inductance.

Cheers
KlausB

really? you can reduce inductance by paralleling them?
  Reply With Quote
Old 12th January 2004, 04:34 PM   #8
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
I suspect the more prosaic motivations: cost and space.

From my own diy experiece I conclude that sometimes many smaller caps cost less than fewer big ones, this may be even more the case when you buy in industrial quantities.

Secondly, many small caps can sometimes be packed in to the volume of an enclosure more easily than a few large ones. The opposite can be true depending on the dimensions of the enclosure and the other components.
  Reply With Quote
Old 12th January 2004, 04:40 PM   #9
diyAudio Member
 
mrfeedback's Avatar
 
Join Date: Feb 2002
Location: Perth, Australia.
Default be Wary Of Setting Up Resonances Though.........

An ME amplifier model (850?) runs 100 x 3300uF caps in the psu (330,000uF total).
Limitless psu current capability and it sounds like it too.

Eric.
__________________
I believe not to believe in any fixed belief system.
  Reply With Quote
Old 12th January 2004, 04:44 PM   #10
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
It is true that you divide the inductance by the number of caps by paralelling them.

Im though sure that the inductance of the caps in a powersupply is not an important factor....ESR is though.

As stated before...i agree (unfortunately) that its for prosaic reasons that many smaller caps are used instead of one big cap.

I use big caps with a film cap in paralel.....works as good as anyone could ever ask for. If you want something better than that, use a regulated power supply.


Magura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  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
ICW Clarity Caps-- 3 lots FS bigLG Swap Meet 1 10th April 2009 10:17 AM
FS: Lots of CAPS Killjoy99 Swap Meet 26 30th April 2008 03:20 AM
Lots of free caps and an SACD player Ric Schultz Swap Meet 27 6th August 2006 03:35 AM
Wanted: PSU Caps 100V, lots of uF Jan Dupont Swap Meet 0 7th May 2003 04:07 PM
PS caps in parallel Bill Fitzpatrick Solid State 6 14th October 2002 09:56 AM


New To Site? Need Help?

All times are GMT. The time now is 04:07 PM.


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