Blowing Fuses. Dennis Had Inspire 300B SET

My friend went thru this, he tried several fuses, tube changes, a repair person, finally back to Maker, came back fixed.

I have a Cary amp from back in the Dennis Had days, and also from back in those days I had a DIY "Power Bank" (a kit from CAD) which consisted of four more power supply capacitors connected to the amp with an umbilical cord.  The amp started blowing the 3A SB AC power fuse on start up (not every start up, but frequently enough that I kept a lot of spares on hand).  I disconnected the Power Bank and now I literally cannot remember the last time I blew that fuse.

With all that typed, I realize that you didn't say that you had your amp connected to a power bank, but, as @dekay  mentioned, your issue could be related to a bad cap, and specifically one of the large power supply caps.

I had a similar issue many years ago with a Music Reference amp. Turned out to be one of the output transformers needed replacing. Not an easy or cheap repair.

I would try a 3A slo blow

@moose89 Please ignore the above advise- never, ever put a fuse higher than the rated fuse in any product unless specifically told by the manufacturer that its OK.

Solid state amps usually have fast blow fuses. Tube amps almost always have slow blow fuses. All the 'zigzag' fuses I've seen are fast blow. I would get a Littlefuse or Bussman slow blow fuse as a replacement so as to know that the fuse you're installing will actually do the job.

If it continues to blow you have other problems; the amp should be checked out by a qualified technician.

@atmasphere Your opinion is noted and considered overly optiomistic at best.  You are a manufacturer and have an overly proud opinion of manufacturers IMHO.  (not that I have anything bad to say about you or Dennis Had). 

erry