Tuesday, October 8, 2013

Class D?

Among all the passionate discussions taking place on audiophile sites I found that I need to find a sweet point between the money, effort I put in my project, the fun I can get working on it and result (in terms of sound quality) I can get at the end.
Since I'm just an ignorant hobbyist I don't see a point to invest too much in my first project. I want it to be both fun and challenging.

So my amp is going to be fully digital class D amp. No analog circuits at all.

The roadmap is:
1. Play music on a device which has a USB
2. Convert USB to I2S
3. Pass I2S to PWM modulator
4. Feed power stage with PWM from the modulator.
Seems not to be super extremely complex.

I found these nice chips from Texas Instruments:
-  PWM modulator TAS5548
- 300W/channel power stageTAS5631B
last one promises pretty good THD up to 100W, but I don't think I ever need that power, especially having active amplification.
TAS5548 can processes 8 separate channels (4 I2S stereo channels) at 96kHz, has two ASRCs onboard and 7 biquads per channel. So it is able to handle all active crossover filters! I like the idea.

So next step is to design a PCB.

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