Atma Sphere M60 owners......

Can I put 6sn7 gtb's in any of the 4 positions, I'm getting mixed info on this. Some say just gt's and not B's. Also what brands do you favor in yours, thanks all in advance.
Maybe Ralph will see this and comment.
Yes, you can put 6SN7-GTB tubes into any of the positions.

The problem is with non-GTB/GTA tubes. In certain positions the voltage is too high for a non-GTB/GTA.
Why don't you just call Atma-Sphere? Ralph doesn't bite!
Thanks, I do plan on that but also wanted some input from other owners on their favorite tubes.
The driver tube position in the M-60 requires either a -GTA or -GTB style of 6SN7.

As you face the front of the amp:

In the MkIIIs and later this is the position that sits by itself in the front.

In the long chassis MkII.3 it is the rear 6SN7.

In the MkII.2 and earlier its the rear right position.

All the other tubes can be GTs. The new Sophias, TJ Music and Psvane tubes are getting very good comments from our customers; essentially saying that these tubes have the strengths of the best NOS tubes without the weaknesses!! It appears though that they may not be as reliable but that is conjecture at this point.

The best of the NOS tubes for the GT positions has been reported universally to be the Ken Rad (which was never available in a -GTA or -GTB). That is followed by the metal base chrome-dome Sylvania (a WW2 tube) then the RCA Red Base, which is the same as the CBS Zalytron.

We don't mind if people roll tubes, just remember that the one position needs to have the higher voltage variant and otherwise don't drive yourself completely bonkers trying to sort out the best combination- IMO you are better off spending the money on LPs or the like rather than tubes on the collector market...
Atmosphere, Thanks for the timely response. Time to go shopping!