I had a fuse blow in the output circuit of this high power tube amp. It made one hell of a sound (like a firecracker!). Inspecting the fuses (I assume they are in the screen circuit but I have no schematic for this thing), I noticed that there seem to be 4 different fuse types although all appear to be 500ma. I wonder if anyone here knows if there is a specific type of fuse that Melos recommended for the 4 6KG6 output tubes-- there is nothing marked on the unit, of course.