Whining noise from engine

[AFOUR_PLAY]

My car has been making a whining noise that comes from the engine.

What could it be?

It is loud in the mornings when it's cold and only happen around 1800 - 2400rpm under light throttle (the car doesn't make boost)
When the engine warms up you can hear it faintly. I was worried that it may be the turbo but the car still makes normal boost levels and holds as normal.

Has this happen to anyone else?
What are your thought?

[A4-Vblack]

Need some more info - but good chance that it is a fan or one of the belts. I'm not a turbo guy, so they might know more as to whether or not it is related to the turbo.

[4ingDrive]

I had a bad power steering pump do that.

[AFOUR_PLAY]

I just had the tensioner pulley and all that done and have heard when that is changed it puts more tension on the other pulleys.
Took it to an Audi expert and he said it's the water pump. another guy said sounds like the turbo.