atmasphere 6as7g output tubes.

Once B+ is applied to a new tube, the preconditioning process is ended. So You don't ever apply B+ until the tubes have finished the preconditioning period.
However once that is done you can apply B+ right away. 

I've yet to see a GE that was trustworthy- I'm guessing that was not a 'G' but a 'GA' in the bantam envelope. GA's of any brand simply can't be used- they grid heatsink is tiny relative to the G variety and so the grid easily warps due to overheating.

Conditioning completed, the tubes which were arcing before still arcs, with the exception of the GE, which is a G not a GA but I don't trust it so I retired it. Listening to it, I can't tell if the RCAs are better,
More powerful yes they are, I can run the middle switch on the MA-1s on the down position and this is with only 12 tubes
More transparent, could be but I can't confirm need to listen more
BUT highs seems to be recessed and veiled a little, less detail which is a big drawback IMO

I guess Svetlana vs RCA you have to compromise on something, and I also guess your "bias" is tailored to the Russian tube not the RCA

I really don't like to give up on things but in my case since I have high sensitivity impedance speakers it is not worth the trouble going with the RCAs, this is a preliminary conclusion, I do have to test more.

I guess Svetlana vs RCA you have to compromise on something, and I also guess your "bias" is tailored to the Russian tube not the RCA

They both bias to the same point.

Got it Ralph, which with the RCA with the same bias they will produce a little more power, run hotter and possibly demand more current for the same voltage bias correct? and also be more prone to failure maybe?

The power output of the tubes has little to do with the bias point. If anything, reducing the bias current will cause the amp to make slightly more power.


The RCAs are properly biased in the amp and will hold up alright if correctly preconditioned (which is about 4 days and nights continuous, whereas the Russian tubes seem to only need 3 days and nights). But this only applies to the 6AS7G and **not** any of the variants (like the GA) which simply won't hold up no matter what you do.