[sdiy] cs4344 DAC output stage

[Eric Brombaugh]

On Sep 14, 2012, at 12:07 AM, julian schmidt wrote:

> what kind of elkos did you use? My board is full of the big aluminum elkos for the DACs.
> I just see the small smd packages on your board. Did you use Tantal? Any pro's or con's for alu. vs tantal besides the size?

No electrolytics on the dual CS4344 board. I used tantalums for DC blocking in the audio path as well as large bypass caps. The F4 + codec board has a few Panasonic AVE style SMD electrolytics in the audio path - they're inexpensive and seem to work fine.

> I see you used an usb power source in one of the designs.
> What have you done against noise introduced from the USB port?
> while using the discovery board (and other usb devices) I noticed a ground loop(?) introducing noise to the audio outs as soon as usb and audio out was connected to the computer.

USB power is an option in the design but I haven't used it except for powering the board during debug. There is minimal supply filtering provided for AVDD, but I expect that there could be issues if the main 5V supply isn't clean. I haven't tested that extensively yet.

> Do you like the overall sound quality of the cs4344?

I've been using this DAC for a few years - no complaints.

Eric