How to test a codec (eval board) with QA-401

I have a QA-401 and wish to test 4 different ADI codec boards: ADAU1772, ADAU1787, ADAU1701MiniZ, and SSM2603. Am I kind of on my own doing this as the QA-401 doesn’t have a serial audio data path. If I test A/D > D/A, I’d get test data but it is not specified in the datasheets this way (A/D and D/A specs are separate). Would I also have to tweak digital filters for optimization of each board? The manual talks about testing a DAC but it is really a digital audio dongle where the pc controls the serial path to it via USB. I don’t have access to serial data from a pc - what would I use to provide it?
I have access to a U8903B (never used one), but would like to use the QA-401 if I could.

Hi @bklein , can you connect these boards to a PC and send them signals from an application such as Audacity?

I have no means to provide a serial audio data connection. This is what I need and am looking for a solution for.
I’m kind of surprised that this subject doesn’t come up.

Given the complexity of testing each half of the codec separately I think we may move to just a flow-through analysis instead. I have not yet begun testing - I have to write a test plan. First issue I see is my confusion regarding the test signal level. The codecs I will be testing do not have 1:1 flow through amplitudes and the Vp-p capability varies as well. So first I need to establish a test amplitude and secondly compensate for any amplitude loss through the codec. Each codec has SigmaDSP capability using the eval board USB connection I can vary input gain or output attenuation. So any suggestions on this process and then once I have a 1:1 input/output structure, to establish a test amplitude? Do I manually increase input amplitude until a noticeable amount of distortion occurs, take a measurement below that amplitude and divide by two for the test amplitude?

Do I manually increase input amplitude until a noticeable amount of distortion occurs, take a measurement below that amplitude and divide by two for the test amplitude

Yes, that seems very reasonable. As a first step once you have the ADC and DAC working, you could sweep the input with a 1 kHz tone and plot the THD or THDN versus input level, and that would give you a good indication of 0 dBFS, and then, as you note, back off a few dB from that and do your testing.