Emotiva XSP-1 Question

I got this preamp today and hooked it up to the power amp section of my Harman Kardon HK990 integrated. It sounds clean with great channel separation and a good soundstage, but the volume is way too low. The HK990 will produce 150 watts into 8 ohms and will make my ears bleed when running from it's own preamp section. With the Emotiva at full volume I'm getting maybe 75....80 db at best. It doesn't appear to be malfunctioning so is it just incompatible with my power amp?