Sam Ash? Stay far away. Are you anywhere near these guys?
http://www.fatsoundguitars.com/about/index.html
Go there instead. They are the real deal.
Sounds like a bad preamp tube, but could just be a cap or connection. In general, power amp tubes slowly weaken with age wherease preamp tubes just seem to go bye-bye. You could try getting another 12ax7 preamp tube (or maybe it is a 12at7) and swapping it for the one that does the trem (there should be a tube diagram on the inside of the case).