transformer Hum

Flying, Sndsel has hit it on the head! It is simply loose core laminations in your power transformer. This is a very common problem so don't feel alone. Placing sorbathane pads under the transformer will most likely do the trick. Your problem has nothing to do with a bad power supply or bad AC power. Please do not run out and purchase an expensive line conditioner as it will not fix your problem.

Thanks everyone for the help. I won't go and by a conditioner becuase after placing the sorbathane...it decreased. I can still hear it, but only if my ear is within 12" or so of the preamp. I guess it is ok now ?

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.

I echo Dekay's inquiry: where does one get sorbathane washers?

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.