I have more or less completed the audio analyser based on CS4398 and CS5381.
In an earlier post I suggested I had reached the limits of these IC's. I was wrong. What I had reached the limit of was getting the grounding "OK" for a single (unbalanced) input measurement system.
I have since built a balanced front end - in fact I simply built a Silicon Chip PCB as it was pretty well what I would do - and integrated this to the ADC and DAC.
It looks a bit like this:
What you see is:
- On the left are two independent power supplies
- In the back middle is a MiniDSP USB Streamer card.
- In the middle back is an interface card that
- Does optical isolation of the MiniDsp USB Streamer
- Does more regulation for the ADC and DACs
- Generates local clocks for the DAC and ADC
- Feeds these back to the MiniDSP Streamer