I purchased a Technics turntable online. There is a noticeable short rubbing sound on each revolution when hooked up through my Unico P. I do not hear it when I spin the platter with amp and speakers off. The turntable is extremely clean and the vintage dealer ran it through a cleaning and adjustiment center.I have checked the ground,reinstalled the new belt, and checked for possible sources of vibration.Any help for an old newbe?