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Simple audio amplifier — Parallax Forums

Simple audio amplifier

TexFlyTexFly Posts: 26
edited 2010-10-15 21:09 in Propeller 1
Hello Everyone,

It might seems like a silly question but...I would like to have a small audio amplifier connected to the proto propeller board. The demo board has a MAX4411 (and uses only PIN 10 and 11) that I can't find around...Does anyone have a suggestion?

I just need to play basic sounds, nothing fancy. The demo board does the trick but I need to have a proto board for my live project so I can use the demo board for the development.

Thanks!

Tex

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-10-02 16:57
    The LM4990 is cheap and easy to use. (It's what's used in the S2 robot.) DigiKey carries them for $1.27 (1). Many favor the LM386, but it requires a rather large output cap. OTOH, it's available in DIP form, whereas the LM4990 is not.

    -Phil
  • Cluso99Cluso99 Posts: 18,069
    edited 2010-10-02 17:09
    IIRC with a couple of resistors and capacitors you can plug into an set of powered speakers. You only require 1 prop pin per channel, so if all you require is mono then a single prop pin. A series resistor R1, followed by a capacitor C1 to ground, followed by a capacitor C2 to the input of the amp.

    For R1 try something like 1K, for C1 try 10nF or 100nF, C2 try 1uF to 10uF (if electrolytic then + to R1C1 junction. You can get a non-polorised 1uF mono.

    Someone like Phil or Andy may be able to give you better values as I have not tried these, but you will not hurt the prop nor the amp with these values.
  • LeonLeon Posts: 7,620
    edited 2010-10-02 17:34
    The TDA7052 needs very few components, and should be easy to obtain.
  • Andrey DemenevAndrey Demenev Posts: 377
    edited 2010-10-02 18:41
    I am using TDA7052 for my current project - sounds pretty good. But my favorite is LM4871 - works fine with 3V supply, has shutdown mode with very low power consumption
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2010-10-02 19:45
    I'd go for LM386, they are super cheap, DIP and there are a lot of examples for using one, including the parallax professional developer board (not on prop version, though). The LM4871 is surface mount only if that is what you want. The TDA7052 has a nice power output but is hard to get (though digikey has it). Jameco has higher power versions of the 386.
  • LeonLeon Posts: 7,620
    edited 2010-10-02 20:52
    The LM386 is a very old chip, gives poor audio quality, and needs a lot of components. There are much better devices available.
  • TexFlyTexFly Posts: 26
    edited 2010-10-03 02:59
    Thank you all for the feedback. I have an LM386 in the drawer and I will start from there...
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2010-10-03 12:22
    @Leon. You have some good points. I'm mostly limited to using DIP components. What do you recommend?
  • LeonLeon Posts: 7,620
    edited 2010-10-03 13:10
    TDA7052, it's available in DIL. Digi-Key has thousands of them.
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2010-10-15 15:40
    Thanks Leon. I really like how the TDA7052 does not use a bunch of external components. The DIP version is no longer in production, though digi-key still has 12000 or so, so i ordered 30 of them. Thanks for the advice.
  • T ChapT Chap Posts: 4,223
    edited 2010-10-15 21:09
    I started using the 7052 and it sounds nice, the only thing that I had to rework was connections getting out of the enclosure. You cannot have the minus output go to ground or be used as common ground, this means panel mound jacks have to be ground isolated. The other thing I forgot on the first PCB run was to DC couple the input which the 386 doesn't require.
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