[Collins] 30S-1 final

[pete wokoun, sr.]

The 30S-1 I'm working on has a 4CX1000A final.  The tech manual also lists 
this as the final.  I've heard and read about some amps having a 4CX1500B in 
there.

Is this a later model change?  I see the tubes specs are almost identical 
except for the plate disipation and filament current.  Can  they be 
interchanged in the 30S-1 or do you HAVE to use what's stenciled on the 
bottom side of the top cover, ie the 4cx1000A?

pete KH6GRT