Building my own HU quality amplifier

Lum · 01-20-2005, 07:26 PM

I would like to build a small 4-channel amplifier that is comparible in quality and output power to those found in a half decent head unit (though if quality can be improved, great!)

The project I'm planning is going to be double DIN sized with enough stuff built in to make it a drop-in replacement for a head unit in any car, however sorting out the speaker outputs has me stumped.

I found a few ICs that do it but they all require a -12V rail and I doubt the one on an ATX PSU would be sufficient.

Presumably this must be possible as single DIN head units do it, but how, does anyone have any circuit diagrams or specific components that could do the job for me.

My electronics knowledge isn't that great when it comes to actually building circuits, so I would probably want to pay someone to build it for me

If someone here wants the work (and is UK based) then even better. Sorry for being lazy.

Scouse Monkey · 01-20-2005, 07:39 PM

I would say that by the time you have bought all the parts and paid someone to do it you could probably just get something better second hand mate. Building a decent amp has a lot to it and i think if you go for an older model from a decent place you will get better results.

Lum · 01-20-2005, 07:45 PM

Quote: Originally Posted by Scouse Monkey

I would say that by the time you have bought all the parts and paid someone to do it you could probably just get something better second hand mate. Building a decent amp has a lot to it and i think if you go for an older model from a decent place you will get better results.

I have not been able to find an amp that is physically small enough to fit though, that is the real problem, of course it would help if the manufacturers provided the dimensions on their websites, it's not like anyone has ever tried to fit an amp into a small space before is it?

powerslide · 01-20-2005, 07:58 PM

http://sound.westhost.com/ - all sorts of plans and designs for amplifiers that you can build yourself. You can also buy pre-printed circuit boards here for very cheap.

http://sound.westhost.com/p-list.htm - a list of all the amps you can get plans for here

www.diyaudio.com - others who build their own amps, ask some questions there

hope this helps!

Lum · 01-20-2005, 08:58 PM

Well, after much googling, it seem like two of these would be my answer
http://www.aaroncake.net/circuits/amp20w.htm
Any thoughts on this design, or what the quality will be like compared to a head unit?

rando · 01-21-2005, 12:21 AM

The quality of those chips should be the same as any head unit that uses them.

I have an early 90's vintage Kenwood CD HU. It uses two Panasonic AN7174K chips to produce 4 14W channels. There appears to be little more than the chips and a few capacitors to the amplifier. The entire amplifier sub-assembly w/ heatsink is rougly 3"x1.5"x3/4".

I have no idea if you can get these chips in low volume (or at all). Here's a link to the datasheet. The Vcc operating range and absolute maximums are perfect for powering directly from your cars power system.

http://www.alldatasheet.com/datashee...C/AN7174K.html

Alternatively you might just look for a used HU on ebay and yank the amplifier.

nFiniteTuning · 01-21-2005, 12:41 AM

Why dont you just get a regular amp? Instead of some cheap crap?

SAScooby · 01-21-2005, 12:46 AM

I think your best bet would be a line driver or two, not an amp but just something to take the low pc sound card output to something higher, visit www.davidnavone.com for info

If I have misunderstood your objectives, please visit the the same site as they have an amazing 20Wx2 RMS amp that is tiny !!!!

either way www.davidnavone.com has the answer for you

rando · 01-21-2005, 12:55 AM

I don't think a line converter will help him. He needs an audio amplifier to hook up to his PC soundcard and power the speakers. He's trying to build a carpc that's self contained (including audio amp) that will fit in the space of a double-DIN HU. That Davidnavone might be a good option too, it looks small and has (comparatively) good specs.

danon · 01-21-2005, 01:43 AM

Quote: Originally Posted by Lum

Well, after much googling, it seem like two of these would be my answer
http://www.aaroncake.net/circuits/amp20w.htm
Any thoughts on this design, or what the quality will be like compared to a head unit?

if my memory serves right, he is an old member of this forum.

Lum · 01-21-2005, 09:52 AM

Quote: Originally Posted by nFiniteTuning

Why dont you just get a regular amp? Instead of some cheap crap?

An amplifier is definately going to happen in the future, the problem is the number of times I find myself in a different car for a few months (usually company cars) It's pretty feasible to drop in a new head unit and later put the original back, without breaking anything, but installing my own amp is going to upset people.