Portable Amplifier IC for 8 ohm speaker

chingyg · 30th September 2009, 10:18 AM

Hey guys, I am looking forward to building a powerful and portable amplifier that can fit into a back pack, and run off a single 12V 7ah battery. I have the speakers sorted out already, their impedance is 8ohm and have a power limit of 100W.

So I am looking for a simple chip amp that can provide an output of 20W - 40W into these speakers. I looked at TDA1560 but I could not obtain them, is there any other similar chips or designs I can use.

Thanks in advance.

star882 · 30th September 2009, 03:05 PM

A TI hybrid should work great for that. A TPA3122D2 will work nicely, but there are some other ones as well.

chingyg · 1st October 2009, 01:26 PM

Thank you very much, i had a look at the data sheet of tpa3122D2, it should work just fine for my application. but I have one more question the maximum gain of the chip is 36dB, so can it be powered straight off something like a mobile phone or an iPod's audio output, or does it need a preamplifier to reach maximum output.

chingyg · 1st October 2009, 06:46 PM

Would this circuit work?
tpa3122.jpg
It is has two op amp working as a crossover network at 4000Hz, the treble goes to a ready made TEA2025 amplifier and 2 8Ohm mid range speakers.
The other two op amp change the single ended low frequency signal into a balanced and inverted signal which passes through one of those 2 in one potentiometer and goes into the TPA3122 input.

I am a newbie in electronics, especially the audio part so any help is appreciated.

star882 · 1st October 2009, 09:23 PM

Here's a friend's design based on that chip:
http://ecorenovator.org/forum/applia...ome-audio.html
Just replace the power supply with the battery. Power output will be limited at 12v, but it may still be plenty. If not, use a DC/DC converter to increase the voltage or use two 12v batteries in series.

chingyg · 2nd October 2009, 02:28 PM

thanks alot, I would use two battery if necessary

30th September 2009, 10:18 AM	#1
chingyg diyAudio Member Join Date: Sep 2009 Location: South Africa	Portable Amplifier IC for 8 ohm speaker Hey guys, I am looking forward to building a powerful and portable amplifier that can fit into a back pack, and run off a single 12V 7ah battery. I have the speakers sorted out already, their impedance is 8ohm and have a power limit of 100W. So I am looking for a simple chip amp that can provide an output of 20W - 40W into these speakers. I looked at TDA1560 but I could not obtain them, is there any other similar chips or designs I can use. Thanks in advance.

30th September 2009, 03:05 PM	#2
star882 diyAudio Member Join Date: Mar 2007	A TI hybrid should work great for that. A TPA3122D2 will work nicely, but there are some other ones as well. __________________ "Fully on MOSFET = closed switch, Fully off MOSFET = open switch, Half on MOSFET = poor imitation of Tiffany Yep." - also applies to IGBTs!

1st October 2009, 09:23 PM	#5
star882 diyAudio Member Join Date: Mar 2007	Here's a friend's design based on that chip: http://ecorenovator.org/forum/applia...ome-audio.html Just replace the power supply with the battery. Power output will be limited at 12v, but it may still be plenty. If not, use a DC/DC converter to increase the voltage or use two 12v batteries in series. __________________ "Fully on MOSFET = closed switch, Fully off MOSFET = open switch, Half on MOSFET = poor imitation of Tiffany Yep." - also applies to IGBTs!

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1st October 2009, 01:26 PM	#3
chingyg diyAudio Member Join Date: Sep 2009 Location: South Africa	Thank you very much, i had a look at the data sheet of tpa3122D2, it should work just fine for my application. but I have one more question the maximum gain of the chip is 36dB, so can it be powered straight off something like a mobile phone or an iPod's audio output, or does it need a preamplifier to reach maximum output.

1st October 2009, 06:46 PM	#4
chingyg diyAudio Member Join Date: Sep 2009 Location: South Africa	Would this circuit work? tpa3122.jpg It is has two op amp working as a crossover network at 4000Hz, the treble goes to a ready made TEA2025 amplifier and 2 8Ohm mid range speakers. The other two op amp change the single ended low frequency signal into a balanced and inverted signal which passes through one of those 2 in one potentiometer and goes into the TPA3122 input. I am a newbie in electronics, especially the audio part so any help is appreciated.

2nd October 2009, 02:28 PM	#6
chingyg diyAudio Member Join Date: Sep 2009 Location: South Africa	thanks alot, I would use two battery if necessary

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