[Amps] Dentron Clipperton L

[R.Measures]

>Happy 2004 Ampers
>
>I just got myself a Dentron Clipperton L amplifier before Xmas. All four 
>tubes were dead flat so I got it for a good price.
>
>I have put 4 new 572B's into the amp and it purrs along very nicely. I will 
>need to set the filament volts to the correct value because we have between 
>240 and 250 Volts AC mains here in West Oz and the amp caters for 230V mains.
>
>Looking at the old tubes which came with the amp, there are lots of little 
>silver/grey couloured little molten metal balls stuck to the silvered 
>surface near the getter and rolling around within the tube envelopes. I've 
>never seen this sort of thing before. Does anybody have any experience of 
>this condition?

**  Are the filaments open?