Was a low pass filter. It basically cut off above 10 to 20 KHz. Today I bet folk expect more than that.
Years ago there used to be an inline filter that could be put between the turn table and the amp. I think it had a name like a pop and crackle machine or some variation of that. It was a dampening device that clamped down on noise generated by vinyl issues. Anyone know what I am talking about and where I can get one.