I just now saw this post. I have an AVA Fet-Valve 550 (I think I'm remembering the model right) in the Pittsburgh area to be sold. I was going to send it back to AVA for repair and sale, but I haven't gotten an appropriate second box to double box it yet. The amp took an input voltage spike on one of the channels and is distorted on that side. If you're interested in that let me know and maybe we can come to an arrangement.
John