TI's TAS3002 digital audio processor

[Mark Evans]

I have almost finished my protoype TAS3002 + TAS5010 digital stereo preamp and equibit modulator board. (see picture)
I plan to us it for
a: experimenting with equalising a sealed subwoofer
b: room equalisation of a pair of speakers
c: to experiment with equibits modulator to make a high power amplifier

Has anyone else successfully played with the IC?

[dmfraser]

I have used the TAS3004 and TAS3103. The 3103 can be made to run at 24/96.

The TAS5012, operated OK at hgher levels but the distortion goes up as the level goes down because you have fewer and fewer bits to work with. However, the big problem is that the PWM modulator from TI has absolutely NO power supply rejection. ANything, and I mean anything in the way of noise in the power supply is passed on directly to the speakers.

You need to be very, very good at regulated power supply design where the load varies wildly.

[fr0st]

That's the same as almost all class D amps. During the both the on and off of the half bridge the speaker is pretty much directly coupled to the supply lines. This is lessoned full bridge however.
No dout they need to be regulated to get the top quality sound you want.

[Mark Evans]

Ok,

I am also skeptical on how well the equibit modulator will perform and to what lengths you need to go to regualtor the main power rails. This project is primarily to investigate these chips capabilities.

I am more interested in the TAS3002 and using it as a stand-alone box, analog in and analog out with a USB port as well. Plug it in to a nice amp+speakers, use a microphone and tone generator (what linkwitz describes)
plugged into a computer. Then generate an equalising filter design, download the coeficients in to the 'black box' and have nicely equalised speakers in that listening enviroment.

What are your opinions on this chip? TI's software package looks promising. The only thing I am worried about is noise at low volumes. If this looks to be a big issue I might use one of Maxims digital potentiometer ICs to control the volume and process all the audio using the chips full range. Are there issues about digital attenuation I should be aware about?