Tripath (RIP) is a company that coined class-T amplifiers with the TA-2020, aka an audio quality D-class amplifiers with some tricks to reduce noise to audiophile quality. Today, there are a lot of chips from Philips and TI used on eBay to offer tiny D-class amps.
The TPA3116 D-class audio power amplifier, 2x50Watt, has a 96% efficiency (vs 40% max for A-B class amps) and can be run on batteries. E-Bay has boards for as low as $10 for 2x50Watt TPA3116D2, 200W 2.1 or even 500W 4.1 for $24 , and even $10 finished amps. Some have bluetooth or other features. There are good reviews on the audio quality from AudioKarma and DIYaudio.
So I bought a diminutive TPA3116D2 for a few peanuts on ebay. It barely gets warm. I power it with a re-purposed IBM laptop power puck. It is housed in a Guess wallet tin box, the 2×4” board leaves ample storage space to pack in also the connection cables.
The sound quality is excellent, and drives a pair of old sony bookshelf speakers with plenty of oompf that I don’t need to crank it. Even full volume it doesn’t feel like it’s clipping much.
- I used this amp on the playa, indeed, and it came back. The main pita is the way I connect the speakers requiring a screwdriver. I’ll change that. If I make an art car I may use a bunch of those to drive hidden speakers.
- I used this amp for a party in a 500sqft hotel room with 60 to 100 people crammed in, and it had enough punch to be louder than the ambient noise with 87dB speakers.
I may want another more powerful D-class amp 🙂 TI has a nice documentation on all its amplifier ICs which allow much higher output wattages. A friend is building up a NS A/B-class LM3886TF analog amp for his tube pre-amp (~60W?).