G.E.C. 6080 / CV2984 tubes - anyone tried these?

Hi all. I have read some good things about G.E.C tubes in general, though not much specifically about the 6080/CV2984. I was wondering if anyone has tried out these tubes. My amp uses 6AS7G/5998/6080/421A etc. tubes and I can get a NOS matched pair of the G.E.C 6080 for a pretty good price.

6080s come in two varieties, one with a large grid heatsink and one with a smaller grid heatsink. Neither tube should be used in an amplifier that uses a fixed bias scheme in the output section. Amps that have automated bias and adjustable bias are examples of 'fixed bias' operation. In such cases the tube will be likely to arc and fail quite quickly!

I would be hesitant to regard the 6AS7G/5998/6080/421A family as being completely interchangeable. This might be true in some amps that employ cathode bias but you will find that output power varies with the tube types as does reliability.