Persistant Chirping

I have seached and searched and couldn't find anything on this. I have a constant chirping that coming from under the hood of my 96 Jimmy. I read a few similar posts but nothing has worked. I replaced the alternator, water pump, idler pulley, and belt tensioner and still have the same problem. The chirping gets faster when the rpm's go up so I know its probably a pulley. Has anyone had a similar problem?

A/C Compressor?

Get a stethescope and listen to all the rotating components with the engine on and see if you can hear it or bearing noise in any of them.

I think its my belt. Someone told me to put a bar of soap on the grooved side of the belt with it running and it stopped the chirping. I have no idea how that worked, but it did. Thanks anyway.

i cleaned mine with brake clean and a wire brush and it worked

You replacedall those parts BEFORE checking to see if it was your belt??