Amp Advice

hatred

Member
2010-10-13 8:09 pm
Hi,

I need some help with a new design if it is possible please. I am a first year Electrical Engineering student, so my knowledge of amps and all its components are still stretched thin.

The idea that I had in mind, was to build a amplifier for my car. I have been looking around a little bit on the forums for schematics and have found quite a few. I am, however, unsure if these amplifiers will be able to function on only a 12v input.

At this time my car only has two 6x9", 260W , 4 ohm speakers in. So building a low watt amplifier might be more suitable, however, if i should decide to buy a sub later, then it would be more logical to rather build a high watt amplifier.

If it is possible, and anyone that would share some insight (or some schematics :p) for such a amplifier it would be greatly appreciated

Kind Regards
Ruan
 

ptempel

Member
2008-07-09 11:13 pm
A class D or T amp would probably be the best for a car. Some places I've looked at are:

Class D Audio Car Audio - PRODUCTS
They only sell pre-built but have a good reputation. Also sell an smps module.

41Hz Audio - News
They have a big selection class T Tripath amps. Was looking at amp3 or amp9 (4 channel) for the car but amp11 would be better for subwoffer. No smps kit there.

ESP Projects Pages - DIY Audio and Electronics
ESP has a lot of amp and other projects with schematics. See project 89 for discussion on an smps. A great source of info (go to the bottom of the page and click on main index link).

SMPS Switching Power Supply Design: Circuits and Schematics
Talks more about smps theory and has a few links at the bottom for schematics.

http://www.diyaudio.com/forums/car-audio/31614-making-car-amplifier-smps-tl494-dc-protection.html
A car smps discussion right here on diyaudio.

DIYMA.com - Car Audio Forum & 12 volt Community Board
A forum that focuses on car audio more but has less DIY projects. Remember reading a thread about a guy adding a 41hz amp to his double din head unit.

Hope that helps. Most of the theory is over my head so I'm still one of the beginners that would need a kit or a PCB with good instructions. ;)
 

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djk

R.I.P
2001-02-04 4:23 am
USA
" DJK,
I can't find that graph in the link you posted."

The graph is from their car audio selection tree.

"Does a ClassAB amplifier powered from a single 13.2Vdc supply really draw ~900mA of current when the output is 200mW into 4r0?"

It doesn't make sense, does it?

I can't find the data sheet for their Class KB part.

My calculation shows all four channels at 200mW plus Iq should draw about 14W at 13.2V (1.074A)

I can think of a way to get a curve like the KB curve, but it would require a rail switch like the one in the National Semiconductor patent on the bridged LM3886, and a buck-mode switching regulator for the lower rail. You could put all the extra stuff inside the IC, except the inductor.

"Good circuit, but essentially a copy cat of stmicro TDA7560... "

I think it may be better in some respects, the pin-out is the same too.
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