Build a Simple Audio Amp

first-amp

[Ynze] has built an audio amplifier that looks and sounds great. His amplifier uses a National Instruments (now TI) LM3886 Overture series 68 Watt power amp. The LM3886 places [Ynze's] amp squarely in the “Gainclone” catagory. Gainclone or Chipamp are terms long used by the DIY community to describe audio amps based upon highly integrated semiconductor amplifiers. The Gainclone name stems from the original Gaincard audio amplifier sold by 47 labs. The Gaincard used less than $100 USD of parts when it was introduced in 1999. It sounded good enough to command a $3300 USD price tag on the audiophile market. The low parts count and simple construction spawned the audio DIY community to build their own versions of the Gaincard. Hundreds of variants exist now, and wading through the different versions can be a bit of a daunting task. [Ynze] found a basic design that works, and built from there.

One of the interesting things about [Ynze's] amp, as well as many of the Gainclones, is the fact that they use no circuit board. All wiring is done point to point. resistors are soldered directly to the pins of the amplifier chip. This can be some tricky soldering for beginners, but several PCB kits are available. [Ynze] built his amp in two cases. One case holds the power supply, and the other contains the amplifier itself. [Ynze] is using a large toroid transformer to drop his local 230V mains down to +25V and -25V. The amplifier circuit itself is simple – a few discrete components surround the LM3886 and it’s heat sink. [Ynze] also did some very nice carpentry work on his wood chassis. The resulting amp looks like it’s right out of the 1960’s – but hides 1990’s electronics inside.

Comments

  1. bryan says:

    for more info, go over to diyaudio.com

    there is a forum devoted entirely to chip-amps.

    while the CA’s are nice little amps, this is hardly a ‘hack’ anymore. but then, I bet there are many who have not heard of this yet. this isn’t really a ‘hack’ site anymore, but just a news/announce site of various cool projects.

    • Mental2k says:

      I came on to recommend that exact site. Great bunch of guys always willing to help. Even if if it’s just to sate your curiosity. On a related note, I have the parts on order for my first Cmoy. Should really write up some of my projects. Probably be decent fail of the week material!

    • dave says:

      That heatsink is a hack, but if it does the job….

  2. geahui says:

    I wish you could use arduino as a loudspeaker amplifier. It’s so funny to use and you don’t have to learn anything.

  3. prignony says:

    I did build a LM3875 based amp 10y ago, and it is still working perfectly. The sound that come out of it is much better that what I get out of my cinema yamaha amplifier.
    If you want to star with amplifier, build this one, you’ll be rewarded directly. It is easy to make you can make it work with as little as 9 passive elements. Then you have to design a good alim and you are done ;)

  4. static says:

    Way back when Radio shack carried decent smaller, component stereo, components for decent price. Looking for an option for for my desktop audio I went to look to see if they stilled carried them, to discover they don’t. While I’m not surprised there is, I didn’t realize that a community has sprung up around the audio amplifiers in a small package. I should dig out the lower power on I have in a parts box and see if I can find a spec sheet for it. Going to be either that or consider a flat screen TV “sound bar” from Walmart, depends how deep the junk box is.

  5. eggs tyrone says:

    Same here, built an LM2875 amp 11 years ago with 4 parts (5 including the LM3875) + a power supply. Still works great, sound is excellent. It is actually what got me into electronics in the first place.

  6. Galane says:

    $3,300 for an amp built from less than $100 in parts? An audiofool and his money are soon parted.

    • Danny says:

      “An audiofool and his money are soon parted”

      yeahh, that has never been a problem

      “ohh here’s my Unobtainium/meteorite/fairy dust – audio cable, the guy who sold it to me said it works as a superconductor and transport the audio faster than the speed of light, only $5000 a foot”

    • mojojoe says:

      It turns out that shielded optical cables with gold plated connectors are actually a thing. It probably helps with the alignment of the sound particles and filtering out low quality electrons.

  7. sobachatina says:

    National Semiconductor not National Instruments.

  8. sleeper service says:

    i cant see this sounding good. those chips are always a harsh sound.

  9. gabriel says:

    hardest part of any DIY Amp: sourcing large metal knobs!

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