Distortion at Peak Dynamic Levels

I'm pretty sure I have a problem in my analogue set up but I'm not sure where it is. At peak dynamic levels I'm sometimes hearing soem distortion that sounds like a kind of hiss, usually on vocals.

I just bought both an Ayre AX7e and a musical surroundings phenomena II and having trouble determining weather the problem is in one of those components or the turntable (Project expression III). I bought the Ayre on Audiogon so I want quickly determine whether the problem is in the amp or another component so I can close the sale.

Can an amp cause that type of distortion? I do not hear any distortion if I use a digital source.

Any suggestions on what the problem might be and how to fix it would be greatly appreciated! Thanks