Crackling sound then nothing
I have a VAC PA100/100 amp. Tonight after turning the amp on, as it warmed up, there was a quick crackling sound. This has never happened before. I tryed to play an LP and nothing. I then tried to play a CD and everything sounded fine. Then I played an LP for a few minutes.
I noticed that two of the four bias lights were red so I re-biased to green. Everything was fine for about 10 minutes. Then a very brief crackling sound and the amp went dead. No power.
I pulled the fuse (Slo blow 4 amps) and it was toasted. Amp has always worked fine. All Tubes are about a year and a half old. Before I put in another fuse any opinions on what went wrong? Any damage that may result?