RK3308 Audio ADC

I was rather hoping to get the newer SoC revision of the RK3308-BS but got the older silicon but thought what the heck I will try the 4 mic channel ADC anyway.

What ever I seem to do with what might be considered ‘normal’ electret based bias circuits in terms of capacitors the gain seems very low but the noise levels are terrible with SNR of near 1:1
I am been using single ended circuit inputs and various capacitor values and not made any headway into the problem and just thought I would ask if anyone has actually managed to setup a reasonable signal on the ADC and how?