Alternator strange noise

[toilet2000]

Since I changed my alternator, there's been a strange "noise" that seems to be coming from it. It sounds really like an electric motor noise (like a hum) but somewhat loud (louder while in front and in the car that the actual sound of the engine... and I have the sport exhaust of the ST). The sounds goes louder and higher in pitch while i rev the engine. Any ideas what causes it?

It doesn't seem to alter anything in the car (the alternator works well), but it is really anoying, and im afraid it'll cause trouble later.

Anyway thanks for your answers!

[matmatician]

Probably a belt or possibly the tensioner. I could be wrong though, I'm sure someone else will know more. If it's just a squeaky belt, it shouldn't cause any trouble.

[amc49]

If you could describe it as a whine then alt should be checked, diode failure can make them whine............or alt bearing itself failing.

[toilet2000]

its not much of a whine... ill check the belt tensionner (i replaced the alternator myself, so maybe i did something wrong to it). From the interior of the car, i dont get the "nice roar" of the engine, i only hear the noise which sounds like a vaccuum cleaner that goes louder with the rev