DJM-S9 Aux Input Level

I have my drum machine connected to the Aux Input of my S9. The device is a Roland TR-8S. I have the Aux AND the TR-8 all the way up to unity and feel it is too low. I have to turn the gain way lower than I'd like on my serato channels to get a decent balance. Is this a limitation of this mixer? I feel I should not have to crank the device, it's even on a "Boost" mode to drive the signal past unity.