I have a Dual turntable and I'm unsure of what connections to use on back of my STAV-4090 tuner. Should I use AUX. ? I have tried that and have to turn the volume almost all the way up and even then I get only high end sound. Or is my connection right and my cartridge on phono is bad ? It is an older Audio Technica cartridge (AT14s). Any help is appreciated. Thanks in advance.