DC5 sudden shutdown and blown fuse - advice needed

[herrball]

Hey guys

So I was playing my DC5 for about 30min when all of a sudden a low fizz sound happens for about 3scs and then the amp shuts down.

Power and preamp tubes are fairly new and have about 50hrs on them and the amp has been running fine and sounding great.
I checked the fuse and it was blown. I replaced it and the amp is running fine now; same great tone.
My experience in the past has been fuses blow as a result of some other problem but I can't figure this one out. No funny glow to the tubes (I realize you could get a bad tube even if its new) and no weakness in tone of volume.

Could a fuse just blow due to age? I bought the amp used 2 yrs ago and don't know the history on it other than it is a B version of the dc5. Would an original fuse wear out over time and blow like a tube? I have some gigs coming up and can use my MKIII but not sure if I need to get the DC to a tech.

Any advice/input woud be greatly appreciated.......

 

[scottcrud]

I would check the power tubes first. Take them out and inspect them, is there a dark spot on either? Take your watch off and shake the tube next to your ear and see if there's any rattle...Do you have a spare set of tubes? Put in a new fuse and try the spare set.

 

[MrMarkIII]

A blown fuse indicates problems. Just replacing the fuse will not cure said problems. Fuses don't "wear out". Well, maybe if they're ancient. I would put 6L6s known to be good (your Mark III?) into the DC-5 and run it through its paces, like play at gig volume.

 

[herrball]

I did replace the fuse and no problems yet, been running the amp hard. I'm thinking its one of two things. The power tubes are fine but my central air did kick on with a big surge when the amp fizzed. possibility? maybe,.
I did notice today that the farthest tube on the left (from the rear view) is glowing much brighter than the rest and the clean channel is not as clean as normal so I'm going to give that a replacement and see if it fixes the problem.

 

[herrball]

When I started testing tubes, I know the amp was sounding fizzy before I started. Eventually it turned out to be the Power tubes. Really surprising since they are almost new. Oh well, I guess you can get a bad batch. $40 down the drain.
The price of tone..........