I made a simple PCM2704 dac, it worked but there is a serious problem, i can hear a buzz sound that that's very annoying. Then i plug it in my QA400 and here is the result:
[IMG]i.imgur.com/.../IMG]
The DAC connect to QA400 with 10kohm load, no signal playing, that buzz is clearly visible at around 9khz and 18khz
[IMG]i.imgur.com/.../IMG]
Dac playing -2.5dbfs
This is my layout, hope some one can help me to find out the problem.