I just recorded some comparison sound samples with the F2B and F1X.
https://drive.google.com/open?id=1CuFXYFLe1-BKiwT0gQL0kSLRXLQKBhwvSetting:
1980 Series 1 (both pu, max filters, Q@0db)> DS5 > F2B/F1X > Universal Audio Apollo Twin > Logic Pro X > 24/48 Wav
Each sample is F2B first then F1X second.
The current test settings are as follows.
2-10-2
2-10-2 brt
5-5-5
5-5-5 brt
F1X is recorded through the full range out.
My observation is that to achieve unity gain between F2B and F1X, I had to have the volume on the F2B around 2.8 and the F1X at 5. The F1X also had significant volume loss when set to 5-5-5.
Let me know if you guys want any more samples. I have an SF2 that I sample also.
Thanks!