How to bias Sonic Frontiers Line 2?

Kr4- trust me there's nothing in the manual, other than
telling you not to touch the pots.

Are you adjusting bias or balancing phase?

Well, I checked the schematic for the Line2 and what has been suggested balances the bias between the two sides of the 2nd 6922 (voltage amplifier stage) in order to help insure balance between the two phases of the balanced output. There is no way to adjust bias directly nor any adjustment for either the input 6922 or the driver 6922.

Kr4,

I just got a used Line 2. Where could I get its schematics?

Dunno. Try Chris Johnson at audioconnexions.com