[Amps] 4CX800 - GU74B

[Gary Myers]

Questions:

Are these the same?
If different in what areas?

I recently bought 3 of the GU74B's and it came with a sheet that
said it was thought to be the same as the 4CX800 but some
suggest it acts more like a tube of higher (lower?) plate
dissipation rating.... and the data sheet says 600W not 800W for
the dissipation.

The tubes I bought were of course (? - see later) used and
unfortunately were not well packed when received. There is no
connection on one for the cathode on pin 2 (pins 4 and 6 are
together but not connected to 2).... I would guess this is a
no-no correct?

Since the damage is "visible" or better stated measurable in one
of the tubes there is some likelihood that the others might have
internal structure weaknesses... correct? Is it safe to "burn"
these in in my Acom 2000 amp (do the filaments for 6 hours) or
is it possible that they could damage the amp?

The shipper of the tubes is going to file for an insurance
claim - but finding these tubes is getting to be impossible so I
was wondering if I should try to see if the remaining 2 (I
bought 3) are good...

ARE THESE TUBES BEING MADE NEW ANYWHERE?!!!!

thanks for your considered response.

Gary
K9RX