Is your amp working? From what you wrote it sounds like you are saying two preamps arent working correctly -- that is less likely than one piece of equipment not working. It sounds like you amp isnt adding to the preamp signal, just passing on the preamp signal that it has received. maybe you need to take your amp also to your friends and also hook it up to his preamp,
As for the 990 --
I am sure you did NOT get a returned item -- Outlaw is meticulous in labeling B items when they sell them on their web site (in a special part of the site). They dont just rebox and mail out as if still new.
I think you need to call the Outlaws and talk directly to them after you check out your equipment at your friends. -- the Outlaws are wonderful at supprting their customers. good luck.