Ground Hum with Rega RP6, Exact and TT PSU.

It sounds like you have too much gain. If your Aragon has any type gain adjustment, make sure its on the lowest setting. You may end up having to get a different phono cart or phono preamp.

If you know someone who will lend you a MM cart, try it. 

" Sfall mentions to lower the gain which It is already done. "

Its probably still a gain issue. The Exact puts out 7.0mv. Just to give some perspective, a very common high output cart like the DV10x5 puts out 2.5mv. Most likely, nothing is broken, you just have a mismatch. Your dealer probably didn't say anything about it because its a package deal and they didn't want to lose the sale if they told you it would be necessary to buy a phono pre as well.

Call your dealer Monday and tell them the cart they sold you puts out 7mv and is over driving your phono preamp on the lowest gain setting, and see what they say.

" Only have about 40 hours on the cartridge so hate to change but it my be the solution. "

Phono carts go through a lot of break in. There were times when a new cart sounded so bad, I thought it was broken. 40 hours is a good start, but don't make a decision until you have at least 100.

I would still ask about the 7mv. It can't hurt.

Also think about the rest of your components and if you made any changes at all. Even if you don't think its related. Here's an example. Lets say your system sounds fine, and then you buy a new pair of speakers, and now you have the same noise issue. Your first instinct is to blame the speakers, but in reality, the problem may lie elsewhere. Its just as likely one of your source components has a lot of gain, If your new speakers are more efficient than your old ones, you can easily get the same noise. Nothing is broken, its just a system matching mistake.

The above is just an example I made up so you don't overlook anything. Either way, there's no reason to worry, or get upset. Problems like this are usually easy to diag.