12V Power Supply ? - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 28th May 2005, 07:03 PM   #1
diyAudio Member
Join Date: Aug 2004
Location: Argentina
Default 12V Power Supply ?

I searched the forum and i found someuseful posts but cant find the right answer...

im learning electronics in home (i buy 2 books and i study from it).

im an DIY learn too

first, sorry for my english, im from argentina and my english is not very good. i already learned how biasing transistors, and im study right now how AC signals works in transitors....

my main objetive is create an 4x100W RMS Car amp.

so its 400W of power, at 12-14V its 12V*xamps = 400W => xA=400W/12v => i need like 33A.

is possible to get that from an simple car batter? when i goto and design my amp i need to use the source of 12V? or i need to use some kind of inverser so ill get more vols?

hope you guys understand my question... i serached google and the forum but cant get the right answer abt how many volts i will need and how it work

  Reply With Quote
Old 28th May 2005, 08:37 PM   #2
The one and only
Nelson Pass's Avatar
Join Date: Mar 2001
The simple answer is yes, but it assumes something like
100% efficiency from the amplifier and/or switching supply
that converts the 13.8 Volts froma car battery to what you
want. Also, be advised that a car battery will only do this
for a short while.
  Reply With Quote
Old 28th May 2005, 09:25 PM   #3
diyAudio Member
Join Date: Aug 2004
Location: Argentina
i fount this http://sound.westhost.com/project89.htm in another thread..

its the switching supply that i need? this schematic will be useful?

when you say that the battery only do this
for a short while.,u mean with the car engine turned off, right? i mean if i have my car engine running i never will be out of power, right?
  Reply With Quote
Old 29th May 2005, 07:45 AM   #4
diyAudio Member
kilowattski's Avatar
Join Date: Aug 2003
Location: Long Island, New York
As long as your car is running your alternator will charge the battery. BTW, building that SMPS is not a trivial project. You will need to wind your own transformers.
  Reply With Quote
Old 29th May 2005, 09:31 AM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
your battery behaves like a very large capacitor supplying the shorter term peak demand and smoothing the alternator's 3 phase AC supply.
The demand from the 4*100w amps will peak at about 600w and your inverter must meet this as a minimum. The continuous demand could be a lot less than this.
The alternator must ultimately meet all these power demands. How big is it? Amps & volts should be in the manufacturers spec.
A 50A alternator is only 690VA and it has other power supply requirements to keep the car running.
regards Andrew T.
Sent from my desktop computer using a keyboard
  Reply With Quote
Old 2nd June 2005, 08:41 PM   #6
rinox is offline rinox  Italy
diyAudio Member
Join Date: Oct 2004
I heard some strange things in this post about power needed by the amp... I don't undertaind.... Pass Lab is a pure class A?
If the answer is yes... ok don't think to put it in your car, but if it is class AB pushed to class A for few watts, maybe it's not so difficult to make an SMPS for it.
May be you can change the bias of the amp without big change in sound, I really don't remember very well the schematic of Pass Lab, but I don't think it's so hard to do it.
Let's ask the guru about this point.
  Reply With Quote
Old 2nd June 2005, 09:24 PM   #7
diyAudio Member
Join Date: Aug 2004
Location: Argentina
well. if i can build an SMPS i can use an gainclone in my car, right?
  Reply With Quote
Old 2nd June 2005, 10:05 PM   #8
The one and only
Nelson Pass's Avatar
Join Date: Mar 2001
Originally posted by samsagaz
well. if i can build an SMPS i can use an gainclone in my car, right?
Not in this forum you can't.

  Reply With Quote
Old 2nd June 2005, 10:11 PM   #9
diyAudio Member
Join Date: Aug 2004
Location: Argentina
  Reply With Quote
Old 2nd June 2005, 10:33 PM   #10
diyAudio Member
Stuart Easson's Avatar
Join Date: Oct 2002
Location: Santa Cruz, CA
Send a message via MSN to Stuart Easson Send a message via Yahoo to Stuart Easson
Default humor...


You may not be completely aware of where you are asking the questions. Here in the PassLabs section of DIYaudio, we tend not to emphasize the use of gainclones too much. They are less DIY and more complete in and of themselves and as such are great projects for someone just starting or looking for a lot of output for minimal effort.

In PassLabs land we tend to the larger, more (dare I say it) manly amps that have huge transformers, massive heatsinks, consume vast amounts of electricity and ideally require at least 2 beefy people to move them. As such they are not ideally suited to the automotive environment.

There are other more suitable sections of diyaudio, such as solidstate, car audio and chipamps, wherein lengthy discussions of the virtues of this chip versus that, and their suitability for car use would be welcomed.


  Reply With Quote


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
Split Voltage Switching Power Supply for Power Amp vectorplane Swap Meet 2 23rd April 2011 11:48 PM
LTspice tool for power amp power supply component evaluation andy_c Software Tools 2 23rd August 2009 05:10 PM
Can i use a computer power supply to power audio amplifiers? destroyer X Solid State 91 25th September 2006 04:36 AM
selling high current power supply for power amps. ericpeters Swap Meet 0 14th January 2005 02:21 PM
heater supply (xformer specs are 6.3V 2.5A) as supply for a power LED? jarthel Tubes / Valves 10 21st July 2003 01:30 PM

New To Site? Need Help?

All times are GMT. The time now is 06:04 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2