Atma-sphere amps best power tubes


This question has been debated before on A-gon but without a clear onclusion. I wonder, is it worth it, to upgrade from stock Russian or China output tubes (6as7g), to American NOS tubes?

It seems that everyone agrees that upgrading the Atma-sphere driver tubes from stock Russian/Chinese to NOS is well worth it. This is my experience also.

I am wondering about changing the output / power tubes too. I wonder if a change to NOS is well worth it also in the output case.

It seems likely, judging from my other equipment testing.

My Audiotailor Jade OTL headphone amp uses 1 6asg7 and 1 12ax7. No surprise - it sounds better with a good NOS 12ax7 compared to Russian/Chinese stock 12ax7.

More surprisingly, it also sounds clearly better with a NOS 6as7g output tube (General Electric US NOS). The improvement is largest with the driver tube but not so much behind with the output tube. Almost 50 50.

A lot of output tubes are involved - 28 tubes in my MA-1 amps. Changing them all is costly, and so I would like to know some user experience before I go into this.
o_holter
Good report, O_holter. Hopefully the RCAs will also prove themselves to be reliable over the longer term, which will then provide a great alternative!
Well it's ten days later, has the perceived lack of overall volume and slam come back? Curious myself because I have a headphone amp that can use 6AS7Gs . Right now I am happiest with 5998s in there (so called "Domino" plates). I have use 6080s and preferred the RCAs. I had some 6AS7G variants but no RCA or other U.S. tubes.
O-holter,

Are you still using Sylvanias and RCA's in the 6SN7 positions of your MA-1's?

-Sam
I am away travelling and also have some speaker driver problems (not tube-related) so it will take some time before I can answer these questions.