Center speaker amp for an iPod

center_speaker_ipod_amp

A few weeks ago we saw [Jaroslaw's] universal credit card spoofer. Now he’s sent in a project that incorporates an amplifier into a center speaker for use with an iPod or any device with an audio jack.

The build has two main components; an LM4950 audio amplifier and a center channel speaker he picked up for $3 at Goodwill. The circuit used is straight from the datasheet and he’s provided the four necessary resistor values for you in his writeup. An old set of headphones was butchered for the audio connector and DC power can be provided by any 6-12V source.

The final circuit was built on some protoboard. The speaker housing has plenty of room to fit everything in for a nice finished look. Pretty simple, and except for the IC, this should be an easy salvage project for most folks.

Comments

  1. Yaffi says:
  2. WeblionX says:

    I wonder how warm it’ll get inside, since it doesn’t seem to have any vent slots.

  3. Nice writeup. Although a 7.5W BTL amp seems kinda overkill for a $3 3″ speaker found at goodwill :)

    I’d have opted for a classic LM386 circuit to save some space.

  4. AnarKit says:

    @Dating for Geeks

    The LM386 has horrible audio quality, especially once it starts sinking a few mW of power and distorting horribly.

    Using the LM4950 might be overkill, but if you use it sanely you’ll never enter the region where it will start to distort in this application.

  5. Ned says:

    I haven’t tried the 4950, but I have built a number of ‘gainclone’ amplifiers based on other National LM chips and have always been impressed. The sound quality is far more than you would expect from a simple chip amp. For years, I wrote them off as cheap low-end substitutes for full-blown distcrete amps. I’d encourage anyone with a similar mindset now to give them a try.

    This ciruit is so simple, I might suggest you could do away with the protoboard and wire the whole thing point-to-point. Though, whether that provides any noticeable sound quality improvements, I’m dubious.

    Overall, I think these chip amps are a great starting point, there’s so many places to experiment / go from here.

  6. Fallen says:

    I love gain clones! And although this isn’t one, it’s a chip amp from national. So I’m sure it sounds great. I agree with the LM386 comment. I used 4 to make a bridge parallel 1Wrms amp…it sounded ok…Alright it sounded bad. I am a fan of wiring chipamps p2p, this one looks do-able.

    Overall a fun little project.

  7. Hi,

    I am fond of technology this type of technology was really great i like it most.

    And this will helpful me so i will definitely use it.

  8. James says:

    Cracking spam there

  9. herrkami says:

    i don’t know why we find this at hackaday. i mean it’s a nice gadget but it isn’t hacked nor complicated nor special. you buy a lm4950 and solder everything together like in the datasheet.

  10. kevin mcguigan says:

    to herrkami. it is on hackaday because some of us out here do not know everything and come here to learn

  11. cgmark says:

    I did something similar only for adding 4 speakers to my pc for surround. If you have an old car radio they usually have the perfect IC for this. The one I had , had a TDA based amp ic with 4 channels at 20 watts. Re-use the heatsink and the ic only required input and output capacitors. And since it was a car radio, +12VDC power device, the pc power supply is great at powering it !

  12. XBox Hacker says:

    Very nice, yet I don’t see how this fits.

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