Can I use ECC88 for my Sonic Frontiers Line 2?

Recommended by Parts Connexion and have tried that myself with all 8. Much better highs and imaging.

same tube for all practical purposes. ecc88=e88cc=6dj8=6922=cca
Perhaps different sound, but will be fine for tube rolling or re-tubing.

Yes, 6dj8/6922/ecc88/e188cc/7308 all will work in the sonic frontiers pre. I think the line 2 takes six and LV2 and V2 are most important positions.

Both are dual triodes. The E88CC (6922) is the premium variant of the ECC88. The E88CC has a heater current of 365ma (7,500 hours average use) while the ECC88 is 300ma. (3,500 hours average use).

They can be used interchangeably in most applications but in linestages and preamplifiers, the E88CC (6922) and E188CC (7308) are preferred because they are generally more quiet than the ECC88. That is only a guideline however; it will depend on the actual pair you use.

Check with somebody that knows the SF2 and good luck.