Are you referring to the distortion as you turned up the gain, thru 70% or so, Fred? not a prob if you use the master volume on your receiver and leave the 500 at max.
Not sure. All I remember is there was funny stuff going on at certain frequencies on some units.
If you want stability below 4 ohms, why not go with the Peavey IPR1600. Its class D so nice and efficient and has been bench tested at 2 ohms.
The only downside is that it has a fan.
Fred
------- Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!