I use Reaper, the Radial RMP, & a KA6. What I do to make up for low/lost signal is just put my hardware output at +6db in Reaper...
It kinda stumped me too when I first got the Radial, but after a while of fiddling with it, I finally found a setting I could live with...I personally think it's best to leave your di fader at "0" & use the hardware output to adjust the gain, otherwise the di clips in the daw (I dunno if this would make any difference or not, but just to be sure I use the hardware send to boost the output)...
You can even automate the send to simulate rolling the guitar's volume knob back...Reaper is the shizzle...
It would be nice to know exactly what's what, but after about 3 years of testing back/forth with my gear, the results I get are good enough for me, but please do post what you find out if either of the companies reply to you...
Wanted to thank you again for that tip. Tried it this weekend extensively and it does work. And I was able to find some interesting things...
Since I was lacking a lot of dB, I first tried to push the hardware output all the way to +12. At that level, the clean original DI guitars, after being reamped with that +12, starts to be distorted. I figured out that it starts to distort the sound above +9. But my surprise was when I saw that, even at +12, my fadder was indicating a Reamped peak that was still slightly lower than my original DI. So I zoomed in on the two signals and the Reamped one was actually showing a signal that was obviously bigger than the original DI. When using +9 hardware output, it was roughly of the same size...
So I guess my fadder was perhaps not indicated the good information between peak or RMS or whatever... I don't know.
In the end, I hear a little bit of a tone difference. My guitar pick-ups are slightly brighter, with the low end being tighter. The reamped signal was a small bit more muddy I'd say... not as bright or tight. Could be a lot of things... after all the chain is different (1st chain = pickup - TS9 - ENGL Invader - ENGL XXL - SM57 versus 2nd chain = KA6 Output at +9, ProRMP maximum level - TS9 - ENGL Invader - ENGL XXL - SM57).
I want to experiment with a clean boost before the TS9, using something like a XP Booster or Mini Katana. Just to hear the difference if I don't push the hardware output to +9. Maybe leave it at 0 and see how it sounds like with the clean boost.