atmasphere 6as7g output tubes.

Morgan Jones, he of "Valve amplifiers" fame, has written a piece on baking tubes that might be of use here. It's a variant on what Atmasphere talks about above, but using an oven to speed up the process of activating the getter flashing to absorb residual gas. Reductions in grid current are measured and found to be quite substantial, so long as you take care not to damage valves with phenolic bases.

Morgan Jones, Baking Valves

Preconditioning can double the life of the tubes, help restore a better vacuum by activating the getter, and will also reduce the possibility of premature arcing.

BTW this process applies to all output tubes, assuming they are new/untested or NOS.

Atmasphere, this is very interesting. All is not just 6as7g variant but ALL power tubes.

If you apply B+ during that period the preconditioning process is ended.

I assume this is not done during tube testing/matching?

called Ralph at atmasphere again, he said that the output tubes would really change the sound. He recommended the Russian 6as7g output tubes. He also recommended turning the amps on stand by for 3 days as mentioned above, which can sometimes double the tube life.

That should have been: The output tubes would NOT really change the sound.

Toothman,

Regarding output tubes for the S-30 I disagree, with all due respect. I spend 6 months sourcing tubes for the S-30 and the difference is night and day vs. the stock tubes.