Looking for simple, low power & cheap audio amp ICs

Discussion in 'General Electronics Chat' started by IcedFruits, Aug 8, 2015.

  1. IcedFruits

    Thread Starter Member

    Jan 15, 2014
    Hi, I am looking for suggestions to some simple, low power & cheap audio amp ICs, with following set of requirements.

    # It will be powered by a 6v lead acid battery. (for anything that needs higher voltage, i may have to use a boost converter, which may not be ideal for enjoying music, i guess)
    # It will be driving a pair of 4Ω 2.5" speaker for in room personal use, probably will never be volumed up above 0.5W each channel i think.
    # Should not be having any audible noise for no signal or anything. While playing with above power, should not have any distortion either.
    # should be compact and easy to make.
    # Audio source will be a mobile fone or pmp, probably will be over bluetooth or may be just cord.
    # Chip should be common/popular and easy to find.

    While searching, found some results:
    1) TBA820M
    2) LM386
    But some people saying, both above produce some noise, and I am worried about their o/p capabilities @6V.
    3) TDA2003
    this one seems capable, but looks like price is higher a bit.
    4) TDA2822m
    Not sure what to expect from this, but this one IC can drive 2 channels.

    So, please suggest & share your views. I don't want to get into too deep into technicals, just looking for good quality with portability.
    Last edited: Aug 8, 2015
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    All will be kind of noisy vs anything you are used to listening to. Most will sound like an old AM radio from the 1970s. Some hiss, weak bass. 4 ohm is a big (too big) for some of those chips.

    Also, 1 watt of power (LM386) is small buy most standards.
    - What kind of speakers are they
    - How big is the room, and
    - What are your quality expectations?
  3. absf

    Senior Member

    Dec 29, 2010
    From the size of your speaker, I think 1) and 2) should be what you're looking for. They are easy to find and also very cheap.

    I use LM386 as an audio detecting probe with ear-phone for repairing electronic organs.

  4. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    I wouldn't worry about it as the limitations of the 2.5'' speakers will likely exceed those of the amplifier.

    Small assembled amplifier modules (and complete cased amplifiers) are so cheap now that this kind of thing really isn't worth building.
  5. AnalogKid

    Distinguished Member

    Aug 1, 2013
    The 386 and 2822 are simple to use, reliable, and are well behaved. The other two, especialy the 2003, are very sensitive to decoupling capacitor placement, board layout, and wire lengths. In other words, look at them funny and they oscillate. All audio power amp chips are more sensitive to these issues than regular opamps, but the 2003 has given me fits in the past. If you don't need its higher power capability, I'd start with one of the others.

  6. IcedFruits

    Thread Starter Member

    Jan 15, 2014
    Yes, lm386 appears to be very popular and cheap, but i am worried about output power. @6v TDA2822m datasheet says can deliver more power, with much less distortion. From practical listening experience how these two compare ? Any other portable class chips are there to take a look into ?

    bypass cap should be of no issue, 10-16v 470uf caps are small enough to fit 1 or 2 piece on the board.

    I actually prefer diy better, than purchasing ready made items for small little things, gives me more flexibility to tweak them as per my needs.

    Well, don't know about 1970s, but AM sounds really very bad for musical listening purpose, if all someone wants to listen to is the voice, then perhaps ok, otherwise very bad for musical enjoyment :D. Oh wait, did they use chips back in 1970s in AM radios ? :eek:

    They are satellites of my old creative sbs series speaker, locked up in cupboard for long. Room is about 20'x10'. Quality expectations mean noise/distortion less sound with at least a little bass, which will give feels that I am actually listening to music, not just ting-tings or people talking.

    Apart from that, I plan to make 3-4 amps, for giveaway purpose to my friends.
  7. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Go to your local thrift shop, and buy a set of used amplified PC speakers for $2.00. That's where I have gotten some stereo IC amps already built onto a PCB. Was able to use the speakers/enclosures for another project, too. They even threw in a Wall-Wart power supply...
    KLillie likes this.
  8. ian field

    Distinguished Member

    Oct 27, 2012
    Another popular choice is the TDA7052 BTL amplifier, it can give surprisingly high output power from a low Vcc.

    The TDA7052A has DC volume control.
  9. IcedFruits

    Thread Starter Member

    Jan 15, 2014
    Thanks for the suggestion, the specs look interesting. Have you heard it, how does the sound actually feel ?

    Yes thanks for the idea, tore apart my old speaker set from 2001, and found TEA2025B inside, with lots of caps and a hot transformer (power supply). Before it, I played it, the music was like firecracker sound, and took quite high volume input from the pmp just to play it. Will test it more sooner or later.
    Last edited: Aug 9, 2015
  10. ian field

    Distinguished Member

    Oct 27, 2012
    They're DC signal path all the way through, so no C/R coupling colouration of the sound.

    Its the least components you can use to make an amp, no output coupling capacitor. The bulk amplifier ripple on the Vcc line is largely self cancelling, so you don't need a *BIG* decoupling capacitor, but you do need to bypass the HF stuff.