sounds like maybe a clutch release bearing. what vehicle
how long ago was the clutch fitted , what sort of noise
PLAIN AND SIMPLE, YES
With just that to go on I would say that your clutch release bearing is going bad especially if the noise quits when you put pressure on the clutch
There may be some drag on the AC clutch when it is disengaged as the clutch 'free-wheels' during this time. When you engage the AC ,the clutch 'locks up' and the noise disappears. If the noise gets worse you may need to replace the clutch, if it stays the same and it not very loud, I would not replace it.
The throwout bearing is bad. the throwout attaches to the clutch fork and presses into the clutch pressure plate when clutch is depressed. You will need to replace this and complete clutch assembly. Make sure that you have the flywheel turned while clutch is removed.
If there is a clunking noise on a 1991 Firebird Formula 5.0 when going below 30 mph, and the clunking noise does not happen when the clutch is depressed, it is probably a problem with the flywheel. The flywheel moves freely when the clutch is depressed. When the clutch is not depressed, it could be that something is rubbing on the flywheel, like the clutch plate.
Clutch throw out bearing bad.
When your clutch makes a funny noise when you step on it, you might simply have sand in the mechanism. You can begin by cleaning the clutch. If this does not help, check the clutch slave cylinder to see if it is working properly as it tends to cause a squeaking sound when it is damaged.
That noise is coming from your throw out bearing mate, the bearing that engages the pressure plate of your clutch, many vehicles make the noise, I have seen vehicles with a knew clutch put in and it still makes the noise, id doesnt effect the performance and is too big a problem to worry about.
fan clutch
when the engine weres down
If the RPMs in the engine increases and the speed not, the clutch may be worn out, usually it becomes noise at the same time