transformer Hum


does anyone know how to decrease this problem ?
My preAmp transformer hums (not through speakers)...
Is this because of my power supply ? I already have a dedicated line. Or is it because the transformer is going bad ?
would line conditioners help ?

thanks,
flying
Where do you purchase sorbahane and what form/shapes does it come in? I have seen it mentioned in other threads, but only recall seeing some little half sphere footers of sort that I think were made out of this substance. I would like to try it out on the power supply of a tube amp that I have and would like it in washer form if possible for a rack that I am planning.
Re: Sorbothane, have a look at the following page on their website, www.sorbothane.com/page3a5.htm , it may help you. Email them from the link button and they will give you more info on the available form/shapes and where to obtain, hope this helps, regards, Richard.