Wanted: 12vdc, 5-8 clean watts chip amp for 8ohm FR computer speakers

This topic has probably been covered here. Any links?

Some simple amp that lets thru lots of details and music.

PS: 12vdc 2-4A wall wart
Chip Amp: 5-8 lowish distortion watts
Class: D, T, AB
Computer Speaker: 8ohm, full range Aurasound NS3-193-8A 3" Fullrange 2 liter box sealed.
 
a single amplifier running on a 12Vdc supply can output a maximum signal of ~4Vac. A 4Vac signal is 11.3Vpp. That peak to peak voltage must be less than the supply voltage.

4Vac into an 8r0 load is 3^2/8 = 2W
or 4W into 4r0
or 8W into 2r0
or 16W into 1r0

If you bridge any two of these amplifiers you will get double the power into double the impedance.
Choose two 8W into 2r0 amplifiers. As a bridged pair you can get 16W into 4r0.
 
Lots of bridged amps designed for the car industry. TDA7240A, if you can find it, is simplest. TDA1557Q mentioned earlier is good. As mentioned, must run bridged circuit to get any power. There already was a 12 volt thread - find it and get a lot of ideas. (maybe it should be a sticky, as topic comes up every once in a while....)YMMV
 

Mihkus

Member
2012-07-22 8:01 pm
You better build self osc power supply
Super simple and use LM1876 or 2 LM1875 chips clean 10W for sure.
Sounds wonderful too those 12V single supply amps have very high THD im not kiddin mostly below 0,5 but damn that is noisy and the 12V PC supply AND SMPS AND if not fully shielded it will become EXTREMELY NOISY! damn!
 

Arty

Member
2011-02-24 5:04 pm
the drivers in question are tiny 3" ones.
the tda1557q or any of its relatives will be able to power them.

I see no reason to build anything overcomplicated for this task.
I'd bet there will be no need to even utilise half of what those chips are able to do.
 
The TI TPA3112D1 is a single channel class D chip that will make 10 watts into 8 ohms from 12 volts. I plan to put one inside a guitar to feed a 4 inch Faital Pro speaker. It is $3.16 from Digikey.

The TPA3130D2DAP is stereo for $4.03.

I just ordered the TPA3112D2's and some TPA3116D2DAD's (the 3130's big brother) for a guitar enabled boom box. It will run from 22 volt LIPO batteries.
 

Mihkus

Member
2012-07-22 8:01 pm
AN7522 Will work nicely. I find them in old CRT TV sets to run the speakers.

I'm using one for my computer speakers now, using a 12V, 1A transformer-based AC Adaptor and pushing ~4ohms per channel. It is loud and has good Sound Quality!!!

I got it too and still have it, one of my favorite chipamps!

Nicely 2W per channel but with 50% THD sounds pretty sweet at 1/2W or so.
 
I got it too and still have it, one of my favorite chipamps!

Nicely 2W per channel but with 50% THD sounds pretty sweet at 1/2W or so.

Use a good setup, and you get more quality. The 470uf in the datasheet has it conservatively run to play in a TV. Also the (stock) heatsinking rating.

I use a bigger heatsink. Still gets a bit hot, but the heatsink is over 3X bigger than stock (original heatsink from TV).
I use 1uf poly capacitors for the input, and 2X 4700uf 25V Capacitors fed by a 33uh inductor on the + input. Despite the datasheet, I have been able to successfully drive 4 ohms with a 12V power supply that peaks with light load at 14.5V, but sags down to 11V. The chip lives.

For this guys project, it would be a simple way to have a loud amp either mono or stereo. If he really demands more power from 12V and just wants it good and loud and simple, I would have to recommend a version of a transformer amplifier instead of a chip amp. http://www.diyaudio.com/forums/solid-state/42259-zero-feedback-impedance-amplifiers-153.html
 

hpp3

Member
2012-02-29 6:50 am
I've got a little chipamp I built in a computer power supply enclosure. The chip is a TDA1517P salvaged from an old ISA soundcard and is still quite common and can be gotten cheaply. 2 channels, 6 watts each from 14 volts with 0.1 THD at 1 watt (according to the data sheet).
http://www.nxp.com/documents/data_sheet/TDA1517.pdf
Heat sinking is through the legs on one side if you get the DIP package, but I got cheap and used some copper wire as a twist-tie and secured a small heat sink on the top with some thermal gunk in between. Works great for computer amp duty.
 
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It's going in my sons guitar. Not to loud!!!!......looking to put a 12v amplifier, but with lots of distortion

I hope it's a solid body guitar, otherwise it will be all feedback. Back in the 1960's there was a solid body electric guitar with a built in amp and speaker in window of the local Lafayette Radio Electronics store. I used to go inside and play it every time I went there. It cost more than I could afford then, but I always wanted to make one. I think Mattel (the toy company) sold one in the 80's, and there have been others too.

Now 50+ years later I have started work on making one. At first I wanted to use a tiny tube amp, but all my efforts sucked the battery dry in less than an hour. I tried playing my guitar through one of those $20 Chinese digital HiFi amps and it didn't sound too bad, so I ordered the chips. I am currently making a test board for the TPA3112.