I usually turn off the afterburner in my Recto & record clean with that.
The 5150 is more of a one-trick pony, but man, what a trick!
99% of the time, I'm working with distorted guitars, so might as well get something that's amazing for that 99%
If you absolutely must record cleans with a 5150, use the NORMAL gain input, green channel, crunch OUT, & be very, very gentle with the gain staging.