Question about Cambridge integrateds...540A/640A

My friend is very interested in either of these and we had a chance to check them out here in town. One thing that bothered both of us tremendously was the very audible clicking noise that happens when you turn the volume control. I thought to myself that certainly this can be defeated but I just read the online manual and it says nothing about this "feature". I simply couldn't live with that. Cambridge owners can you turn this off?
bump-No one here has a Cambridge?
i did try these a few months ago, not too happy with its sound.
I have a 640A, and notice no "clicking" at all.......maybe the unit(s) you heard we're defective??