I'm running a Fusion FE402 amp indoors off a 40amp 13.8v power supply and instead of using a head unit I am running it off my sub output off my home stereo and before I go and buy some good subs I just want to know if not having a head unit will affect the volume control of the amplifier and would I still get full volume using just the bass remote. (a bass remote is a seperate volume which connects to the amp for serious volume)