Why not build our own Capacitors? - diyAudio
Go Back   Home > Forums > General Interest > Car Audio

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 31st October 2011, 04:00 AM   #1
diyAudio Member
 
Join Date: Feb 2011
Location: Oregon
Default Why not build our own Capacitors?

I was looking at purchasing one of the phoenix gold Power Grid capacitors to install into my stereo, and when i was looking at the Tantrum version, i noticed it looks like a bunch of smaller capacitors that could possibly be mounted to a circuit board,

Why don't we do that by ourselves and we can make whatever shapes, and sizes we desired??

As well as know how big our capacitors are?
  Reply With Quote
Old 31st October 2011, 04:53 AM   #2
gootee is offline gootee  United States
diyAudio Member
 
Join Date: Nov 2006
Location: Indiana
Blog Entries: 1
(I'm not sure if you're talking about actually fabricating capacitors or just combining them to make new values.)

I guess it depends on what kind of capacitors you need or want, and of what values, and how much parasitic inductance you can tolerate in them.

Some people have tried rolling their own film capacitors. But if you can't roll them with offset/protruding foil edges so you can make and connect endcaps that contact each entire edge of the two combined foil rolls, and instead you have to connect to the ends of the foils only, then you also get a lot of inductance. And large film capacitance values are more difficult to make and are very physically large. And I wouldn't know where to start if I wanted to make an electrolytic, or a ceramic, or most of the other types. However, for small pF capacitance values, you can just chop off a piece of coax (hopefully with teflon dielectric) and connect the center conductor and shield on one end only, as the leads, to make a cap, although you'd need a capacitance meter to be able to trim it to the right length to get the pF value you wanted. Teflon dielectric would give a very high-quality capacitor, with very low dielectric absorption.

As far as just combining values using multiple capacitors of any capacitor type, in parallel or series, in order to make other values, you can definitely do that, easily, whether or not you then make them look like a single package.

But keep in mind that added lead length and/or larger total body length increases parasitic inductance, which is often undesirable.

However, paralleling smaller caps to make larger-value ones does effectively put the ESRs (equivalent series resistances) in parallel, and usually the net result can have a significantly-smaller ESR than one single larger-value cap (e.g. two caps of 1/2 the desired value, in parallel, gives the desired value but only 1/2 the ESR, three 1/3-value caps in parallel gives 1/3 the ESR, etc), and the lower ESR can often be very desirable.

Cheers,

Tom
  Reply With Quote
Old 1st November 2011, 06:18 PM   #3
diyAudio Member
 
Join Date: Feb 2011
Location: Oregon
Adding capacitors together is exactly what i was thinking about doing. If you look at the phoenix gold Powergrid. Which i believe is the trantum version of a 15 farad capacitor? inbetween the fins you can see what looks like the tops of smaller capacitors, but they are piled inside of the case!

i think rolling my own film capacitor sounds like quite a bit of work, to make a functional one.

I think stacking capacitors and making a single package would be really cool, because you could even make a somewhat small one, and well over double what capacitors are in the amplifier as a 12 volt reserve before it enters the power supply. Or in some cases, like the power grid, a big supply, for the whole system that is a run away, but not quite big enough to make a huge alternator or second battery a necessity.

But i dont know what parasitic loss, or the ESR values that your talking about are, or mean. I dont know why a lower ESR is a desirable trait? and why is it that i need to tolerate parasitic inductance?

http://im1.shutterfly.com/media/47a1...D550/ry%3D400/

Theres the picture im talking about, where you can see capacitors inside it.

If you look at more pictures of it, it even has a dedicated slow charge, so that you dont shock the system when you install it.

http://www.clublexus.com/gallery/dat...Gold_006-r.jpg

There is a picture of the Power core, the titanium version. There were also some versions of this powercore that had the RMD plug. The manual also explains how the slow charge works, it has a 1 ohm resistor, that slowly fills the capacitor inside, and then you can install it, and not have an explosion, where your moving 10 farads instantly as soon as the circuit is completed. It also has 3 leds that light up, and it turns on the voltage readout through the remote turn on lead that you connect to it, and i think that the power core is a really cool idea, especially since it is a distribution block, big capacitor, as well as a remote voltage display, and something nice to look at!

http://download.phoenixphorum.com/Ma...e20_manual.pdf

I think building something like this would be really cool, as well as a bit more cost effective then finding one of these big phoenix gold capacitors
  Reply With Quote
Old 1st November 2011, 07:02 PM   #4
diyAudio Member
 
Join Date: Dec 2005
Location: Northern California
I am familiar with the carbon polymer cap banks your looking at, and yes they do combine lots of little and very affordable multi-farad 2.5 volt caps together to achieve the desired ESR and farad ratings your looking into. Something you should know is that building one of these while simple in appearance requires some fair knowledge of cap design and application. One of these banks your looking at are known for burning up inside. And I am only quoting info from a inside source about this. In particular one of those pictured is well know for failing in a flaming way. This is why they don't make them anymore.

If your into big caps and want to bypass all the hype and hoopla of the car audio industry please google search Maxwell capacitors and visit their web-site and get some of the real scoop and info from a cap manufacturer. Oh they also make 15 volt caps for car applications off the shelf straight from the manufacturer of the cap themselves with no middle man adding 60% to the price.
And before you venture into building your own please read up on banked capacitance and the need for voltage drop control across large banks like the ones you mentioned. Maxwell offers both active and passive V drop control on all their products they make. Here again unless your into the technology and the pure physics of the state of the art in this area building your own could be very hazardous. Caps like to vent and sometimes explode when treated wrong, so be very careful with them and follow all the safety precautions the manufacturer and your common sense tells you to....hope this helps some...
  Reply With Quote
Old 1st November 2011, 07:04 PM   #5
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Why to you believe that you need additional capacitance?
  Reply With Quote
Old 1st November 2011, 07:19 PM   #6
diyAudio Member
 
Join Date: Feb 2011
Location: Oregon
Which i just researched and was hearing the same thing! about these phoenix gold capacitors failing.

bypassing audio hype is not something i would be against, because i have seen that the car audio scene likes to hike up the prices because its so 'valuable' to your stereo. And i will look into Maxwell, i know industrial stuff is quite a bit cheaper then going through an audio company,

I know if i were to build one it takes care in knowing what your doing, and how to set it up, and i would be confident in not hurting anything, i just dont know off the top of my head what changing ESR or what the parasitic loss that was mentioned previously means, and how i avoid, or obtain these things.

When my stereo reaches high volume levels, the factory charging system in my truck doesn't quite suffice, but i dont think its far enough away from being strong enough to spend a bunch of money on an alternator, or second battery.
  Reply With Quote
Old 1st November 2011, 07:28 PM   #7
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
The ESR can be seen as a resistor in series with a perfect capacitor. The ESR of many of the bling capacitors makes them completely useless.

To build a large capacitor bank (that will generally be useless), it will cost as much or more than the right alternator.

A battery does absolutely nothing until the voltage drops below ~12.5v and it doesn't deliver significant current until the voltage drops even more.

The only practical device that can provide the current and voltage required by the amplifiers is an alternator. All other devices are band-aids for a poorly designed system.
  Reply With Quote
Old 1st November 2011, 07:38 PM   #8
diyAudio Member
 
Join Date: May 2011
Location: Portland Oregon
Quote:
Originally Posted by Perry Babin View Post

The only practical device that can provide the current and voltage required by the amplifiers is an alternator. All other devices are band-aids for a poorly designed system.

+1

Spend your money on the alternator.....
  Reply With Quote
Old 2nd November 2011, 04:14 PM   #9
diyAudio Member
 
Join Date: Feb 2011
Location: Oregon
So if my investment should go into an alternator, why are capactiors so accepted in the audio scene?
  Reply With Quote
Old 2nd November 2011, 04:23 PM   #10
diyAudio Member
 
Join Date: May 2011
Location: Portland Oregon
My opinion........they "show" better. They have "bling" factor......an alternator under the hood doesn't. Caps do have their place for sure.

Last edited by 503Timber; 2nd November 2011 at 04:44 PM.
  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
what is the difference between silver mica capacitors and ceramic capacitors ?? prorms Solid State 1 6th May 2008 01:38 PM
build my first full ranger,let's build another one:a small fullrange high end pc-spea then_dude Full Range 2 30th November 2005 08:54 AM
Do i need to build main supply (240v) filter?Or build power distribution? thomgun_lc Chip Amps 9 16th September 2005 10:52 AM
capacitors: panasonic FC vs elna RJH vs rubycon ZA capacitors costiss Parts 11 30th January 2003 10:32 PM
differences between computer grade capacitors and small can capacitors LBHajdu Pass Labs 0 22nd February 2002 02:29 AM


New To Site? Need Help?

All times are GMT. The time now is 03:37 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