USB Audio Chips


2007-12-21 7:26 am
Season's greetings!

I am in search for a USB chip for implementing an audio interface for a small amateur radio project. All I need is an good 24-bit ADC-DAC with sampling rates of 48 kHz and, if possible, 96 kHz.

Searching the net, I've found a few possibilities, but all found so far have some constraints.

- The TI PCM290x family is very nice and simple to use, but after building a prototype, I've found that these chips suffer from a sample delay problem between the L & R channels. The ADC passband is also not very clean.

- The Micronas UAC355xB chips are similar to the TI ones (without the sample delay problem). They are used in the iMic USB Audio interface and works reasonably well for my application. The problem is that Micronas does not want to talk to Individuals and doesn't reply to any email inquires. I have found no way to purchase the chip in small quantities.

- C-Media has a few USB Audio chips, but like Micronas, C-Media refuses to talk.

- TI TSUB3200A and TAS1020B. These are very interesting chips and are available in small quantities from multiple sources, but they would need some firmware written.

My question to the group:

1. Do you know of any other solutions?
2. Does anyone with experience in writing firmware to the TUSB3200A would like to share (or sell) code?


-- Edson


2003-09-03 12:17 pm
well, one could argue that the pcm2707 used in the opus is not of the pcm290* familly ;) Gordon Rankin once said that the pcm2702 and pcm2902 were not working in the same way as the pcm2707. Jitter measured at the output of the 2702 was ten time worse than the 2706-7 according to him.