Tube Change for Sonic Frontiers SFL-1 and Power 1

Needs some advice on tube change for Sonic Frontiers SFL-1 and Power 1.

I found the sound of this combination a bit bright, not too sure it is due to SFL-1 or Power 1. Will like the sound to be warmer.

For power 1, I have changed the power tube to GE6550A and was thinking to change the gain tubes (V1 and V6). The set came with sovtek 6922. Any ideas which brands or NOS tube will give a warmer sound?

For SFL-1, the current tube is Amperex BB 12AT7.

It's amazing that companies will use garbage tubes in such nice gear. Lose the Sovteks and almost anything will be an improvement. Keep in mind that new 6922/6dj8's will run you a lot less money than old stock mullard or telefunkens.
It's best to get the preamp out of the way but you're using the pre to 'tweak' the sound, just like myself.

I'm having the newer model SF Line 1. Hoping to see more responses in here as well.
In new production tubes, I have found that the JJ's, NOS Tesla's, and EI's all work very well with Sonic Frontiers amps. The are not as sterile as the Sovteks by some margin.
I got a Line-1 and a SFS-50 and i change my 6922 for 5MP of Reflektor 6H23p-ev from Parts Connextion (45$/MP). 3MP for my Line-1 and 2MP for the SFS-50. Well for me that's the sound i was looking for. Very analog. Warm, neutral, nice high. They are also very very quiet. You have to put your ears at 2 inches from the tweeters to hear some noise. I got 4 Svetlana 6550c for the SFS-50 and will buy KT-88 next time.