Audio Research d79 blows plate fuse


My audio research d79 blew the plate fuse when i turned it on this morning.Change fuse and it blew also.Any help would be greatly appreciated.
pka
Hopefully; it's simply a tube. Another possibility is a
leaky or shorted coupling capacitor(especially based on the
age of the amp). If so; it will either be the 2uF or
.22uF(bypass)/600V, mylars.
Thanks for the response.I'm gonna get a new set of tubes and hopefully that is all it is.