Bruce,

I used a V795 as a pre/pro with a 755 until I got a a 950 and then went to a 990. I will say IMO that the 795 was as good as the 950. I never had a problem calibrating to 75db at 0 volume level with the 975 nor the 990. I can not find a volume setting referenced for calibration in the 990 manual, but 0 is what I used. Do check your night setting and connections to the 755.