12 Volts Hifi Amplifiers - Car & Computer

[halojoy]

12 Volts Hifi Amplifiers - for Cars & Computer supplies.

Cars and Computers use 12 volts as Main power source.
This makes it a challenge to design amplifiers suitable.
Here I am NOT talking about any manipulation of the Power supply
to get a higher voltage.

In most cases a low power amp, using these 12 volts
can be well enough to give enough decibel output.
A car is a very little room, and you sit very close
to your computer's loudspeakers.

Because of the low power involved,
it is okay to drive The Amplifier in REAL Class A.
+- 5.5 volts peak
gives like 2 watts into 8 Ohms, 4 watts into 4 Ohms.
Peak current is only 0.75A in 8 Ohms, 1.50A into 4.

So total idle power at 4 Ohms, will be (push-pull):
1.60A/2 x 12 volts = 9.6 Watts per channel.
We need a heatsink of NO MORE than 20 watts!

I have layed out a circuit, based on an Audio Op-amp
and power transistors for to make a HIFI 12 volts Amplifier.
It is published in my website "HaloAudio".
No copyrights - the idea is for everyone to use freely.

I hope it can be a starter for some good ideas.
How to make the best Hifi Class A Amp for Cars/PCs.

Sure most anyone have some use for a 12 volts amplifier.....
After all, we ALL have cars and/or computers!!!

Another thing is:
This is a very good project for those who
want to make a first DIY-amplifier.
Lower cost than a "several hundred watts amp".
Easier to find transistors in low power range.
After such a project
you could be ready for to build other
"full power" high quality amplifiers.

Have a look at my website.
And share with us your idea of "the perfect solution".

HaloAudio - WebSite for do-it-yourself people

halojoy - owns no car, but has drivers licens and PC, FOR SURE!

[halojoy]

here is my principal schematic
for everybody to learn from



halo - too lazy to calculate component values ....

[JOE DIRT®]

hate to be rude but did you come to this forum to sell your site>???

DIRT®

[halojoy]

Originally posted by halojoy
12 Volts Hifi Amplifiers - for Cars & Computer supplies.

Here I am NOT talking about any manipulation of the Power supply
to get a higher voltage.

In most cases a low power amp, using these 12 volts
can be well enough to give enough decibel output.
A car is a very little room, and you sit very close
to your computer's loudspeakers.

I have layed out a circuit, based on an Audio Op-amp
and power transistors for to make a HIFI 12 volts Amplifier.
It is published in my website "HaloAudio".

How to make the best Hifi Class A Amp for Cars/PCs??
Have a look at my website.
And share with us your idea of "the perfect solution".

halojoy - owns no car, but has drivers licens and PC, FOR SURE!

Anybody have a car?
halojoy the best one there ever was at this place

[till]

hate to be rude but did you come to this forum to sell your site>???

Hey Joe,
let halo post his stuff, he is allright. Also he is a long time member of this board. The one who wants only to sell his site is:

http://www.diyaudio.com/forums/searc...der=descending

[bawang]

Errr.... Halo, sorry to burst your bubble.... The ambient noise level is VERY high in a car, much much higher than a good listening room, unless the car has no engine or the engine is dead! Road/tyre noise is another culprit.

So the assumption that you'll need just a little power in a car is wrong. Whatever little experience that I have told me that to get reasonably loud in a car requires at least 50W (into 4 ohms) per channel..... Especially when you are driving a diesel vehicle....

[till]

bawand, you are right, in a normal case. But is you spend some more money for a real speaker in your car 2w would be enough. You know how much dB 2W would be at an efficiency of 100% ? enough to damage your ear in very short time. It´s more the point car speakers efficiency is lousy today. And they had car radios also back in the tube days. With less than your 50W. And, of corse, there are very silent diesel cars to. At least in germany the very expensive diesel limousines like 400cdi.

/till, who ows a very very loud 20 years old diesel car without any radio in it.

[halojoy]

hey
music in cars and computers lovers!

from HaloAudio - power amp section:

pc-amplifier

A model for a circuit to give a good output from 12 Volts power supply.
An OP-amp controls power transistors. Common collector output for max power.
To be biased for full Class A operation. Voltage drop over R5 and R6
should be max 0.2-0.3 Volt at idle current.
Suitable as hifi power amplifier in Computers and Cars.
Your diy-audio-friend can help you to calculate component values.
Should be adjusted to fit your loudspeakers - 2/4/8 Ohms. [/b]

I will spend some hours to CALCULATE
COMPONENT VALUES to my Circuit Model.
I know there are not many people around here,
that can perform such a task
and get near to the optimal performance.

It is halojoy, AKSA, Joe Rasmussen, John Curl, Nelson Pass
and only a couple of other lucky guys
that has the necessary experience to do this,
without artificial help, Spice, CAD (Computer Aids Design)
and whatever you fancy to be suppported with.

Disabled people
will always need something to help them along!

I will make One version for 4 Ohms LSP.
And One version for 2 Ohms LSP.(
(because of low voltage, we better use loudspeakers
that are Driven more by Current = Use Low Impedance Speakers)

halojoy

Give him A Pen & A Piece of Paper - And
He Give You an Amplifier
Ready to be built!!!

[halojoy]

anybody got a car - to use as power supply?
a good start!

[halojoy]

Originally posted by halojoy
anybody got a car - to use as power supply?
a good start!

Horses - how many does it take?
To make a power supply with enough low resistence
to feed a truly top-of-the-art high fidelity 12 volts class A amplifier.

How many horse powers do I need?
Does 80 hp give good enough energy?

What brand of cars have lowest noise?
How about Mazda? Audi? Mercedes? Old Cadilliacs? Chevrolet ..
We have many Volvo & Saab over here.
Maybe "swedish quality" give good sound of music inside a car?!!


halojoy - finds research to rank best Cars to supply amps
with high fidelity towards the source, is frightenly in lack of
__________________________________________________ ____________________
halojoy - has survived a couple of laps round earth listening to car-radio