12vDC to 12vAC

Cxrazy · 20th January 2008, 06:20 AM

Hey guys,

I built and amp recently that runs off of 12vAC.

I want to use this amp in my car (12vDC). The amp draws a max 30-40Watts. I doubt using a bridge rectifier would be enough -> too much current.

How could I go about cheaply and effectively doing this?

Thanks!

Bone · 20th January 2008, 06:31 PM

It would be a good idea to give us details of the amp you have built and its power supply before expecting someone to give you advice.

Tony

jackinnj · 20th January 2008, 06:34 PM

Use a vibrator.

sandyK · 20th January 2008, 08:05 PM

Use a vibrator.

I am sure he means a Vibrator, as used in early car radios to generate a HV AC supply from a 12V DC source ?. It is rather like a buzzer, which uses metal contacts to momentarily interrupt current flow, thus resulting in a buzzing noise.

SandyK

Cxrazy · 20th January 2008, 09:50 PM

uh... Its a kit I bought at a local electronics store. its a stereo 30W RMS amp.

I'm using a 12v transformer now to take the mains voltage down to 12v.

What else would you need to know?

theAnonymous1 · 20th January 2008, 10:36 PM

Quote:

Originally posted by Cxrazy
What else would you need to know?

Well there are a few possibilities here that rely on knowing how your amp functions.

Amplifiers run on DC, not AC, so what does the other part of the power supply on the amp look like? Is it a voltage doubler, or does it just make a single DC supply?

Going from DC -> AC -> DC in a car would be pointless if your amp just runs on a low voltage single supply. In that case you could just power it straight from the cars DC.

Cxrazy · 21st January 2008, 12:34 AM

Quote:

This small amplifier is constructed around the TDA1521 IC, capable of delivering 2x15W RMS
(4 ohm) or 2x10W RMS (8 ohm). The IC is thermally and short circuit protected. THD: .07% (1W/1 kHz). Frequency response: 7 to 60,000Hz (-3dB). Requires 2x12 VAC, 2A transformer (sold separately). Net weight: 1 lb.

Thats what it looks like. maybe it uses those diodes to rectify AC to DC.

Anyone?

theAnonymous1 · 21st January 2008, 01:01 AM

OK, your amp needs a symmetrical DC supply of up to around +/- 16v. The only real way to accomplish this in a car is with a switch mode power supply.

Building a SMPS is far more complicated than your amp kit. See the link below for details on a SMPS for car audio use.

http://sound.westhost.com/project89.htm

Cxrazy · 21st January 2008, 03:05 AM

I have a broken car amplifier.

Could I somehow salvage the powersupply from this? Building that SMPS is a bit over me tech level

theAnonymous1 · 21st January 2008, 04:37 AM

As long as the power supply still works it should be possible. The voltage might be too high, in which case you can take some turns off the transformer to reduce it.

20th January 2008, 06:20 AM	#1
Cxrazy diyAudio Member Join Date: Dec 2007	12vDC to 12vAC Hey guys, I built and amp recently that runs off of 12vAC. I want to use this amp in my car (12vDC). The amp draws a max 30-40Watts. I doubt using a bridge rectifier would be enough -> too much current. How could I go about cheaply and effectively doing this? Thanks!

21st January 2008, 01:01 AM	#8
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	OK, your amp needs a symmetrical DC supply of up to around +/- 16v. The only real way to accomplish this in a car is with a switch mode power supply. Building a SMPS is far more complicated than your amp kit. See the link below for details on a SMPS for car audio use. http://sound.westhost.com/project89.htm __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

21st January 2008, 04:37 AM	#10
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	As long as the power supply still works it should be possible. The voltage might be too high, in which case you can take some turns off the transformer to reduce it. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
My LM3886 Stereo Amp. w 12-0-12VAC Transformer	Andreq	Chip Amps	27	1st May 2011 05:32 PM
Anyone tried this 12vdc 1A supply?	dublin78	Power Supplies	1	11th June 2009 04:27 PM
How to get +15v and -15v from 12vdc	mbcouple	Everything Else	15	25th June 2005 05:25 PM
12vac to 12vdc what all do i need	Big_Tires	Solid State	5	1st September 2004 11:33 PM
URGENT 9vac to 12vac	Guss	Everything Else	1	26th September 2003 01:54 PM


	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

20th January 2008, 06:31 PM	#2
Bone diyAudio Member Join Date: Jun 2004 Location: Dorset, UK	It would be a good idea to give us details of the amp you have built and its power supply before expecting someone to give you advice. Tony

20th January 2008, 06:34 PM	#3
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	Use a vibrator.

20th January 2008, 08:05 PM	#4
sandyK diyAudio Member Join Date: Apr 2007 Location: Sydney	Use a vibrator. I am sure he means a Vibrator, as used in early car radios to generate a HV AC supply from a 12V DC source ?. It is rather like a buzzer, which uses metal contacts to momentarily interrupt current flow, thus resulting in a buzzing noise. SandyK

20th January 2008, 09:50 PM	#5
Cxrazy diyAudio Member Join Date: Dec 2007	uh... Its a kit I bought at a local electronics store. its a stereo 30W RMS amp. I'm using a 12v transformer now to take the mains voltage down to 12v. What else would you need to know?

21st January 2008, 03:05 AM	#9
Cxrazy diyAudio Member Join Date: Dec 2007	I have a broken car amplifier. Could I somehow salvage the powersupply from this? Building that SMPS is a bit over me tech level

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read