ok, here may be some useful information (also reminder for myself)
1 Recording dry track:
- Create 2 tracks in Reaper and arm both for recording (set monitoring to off):
- 1st track: use IN 1 [Out 1 block L] / IN 2 [Out 1 block R] (not needed, but handy as a reference track)
- 2nd track: use input mono IN 5 [In 1 Instr]
Hit record and play away.
2 Reamping:
- On the Axe FX: go to setup --> I/O --> Audio: Change "Input 1 Source" to USB [Channels 5/6]
- (optional: in Setup --> USB/AES change the levels to something matching, I changed everything to 0 db)
- Change the routing in Reaper: Add new hardware output to your dry track and select OUT 5 [In 1 block L] / OUT 6 [In 1 block R]. Uncheck Parent sent checkbox (not sure is this is needed)
- Create new track, arm for recording, set input to use IN 1 [Out 1 block L] / IN 2 [Out 1 block R], Monitoring to OFF
When you hit play, you can experiment with adjusting the AXE FX settings. Other tracks should be audible as well so you can hear your new sound as part of the rest of your track. Record will record your new sound.
I read somewhere that you have to route the 'normal' tracks to output OUT 3/ OUT 4, but I can't find it anymore in my Reaper project, so you can skipt that apparently.
Hope I got it right.