Will try updating the kernel and report back. I believe it uses snd_intel8x0 driver per alsa and it is loaded
UPDATE - I have installed latest kernel and reran alsaconf as well - same pop.
Argh, why can't I get rid of it this time?
There is known issue with this sound chip and a usb conflict that cause a persistent hum but this is nothing like that, it is a pop, like a volume test - for every single sound even.