What inputs does the Pro 40 have? For a single outboard preamp, I think coming in line level(balanced from the Avalon to a TRS input) will work fine(I would set the GAIN on the Pro 40 all the way down first and see how much it needs to come up for proper recording level from the Avalon). I suspect all the way down may be where that knob stays
. The lightpipe input is a great place to patch an 8 channel preamp(like the OctoPre Mk II Dynamic?). If you have a SPDIF input(I think you do) that's one more option and would make the most sense for 1(or 2) outboard preamps with an outboard converter(such as made by Apogee and Lavry). A retired DAT recorder might also fill the bill
. Some external preamps have a SPDIF option that allows a second input to the converter(because SPDIF is a 2 channel protocol). The old Presonus Eureka may have that feature(not sure as I've never owned one). Lots of options(and tons we haven't touched on) but just remember, no song became a hit because of the converter
