Distortion/too much bass from turntable

Hi I recently acquired a Sony PS-LX7 turntable and everything appears to work fine except I'm getting some distortion. It sounds like it's either too much bass or the sound is too loud and thus distorting.

I'm using a Sony Moving Magnet XL-200 cartridge and a Sony ND-200 stylus. I have it hooked up to a Sony TA-F45 amplifier and have the ground and RCA connections in place correctly. The Cartridge Load switch is set to MM at 180pF.

Incidentally I tried hooking it up to a USB sound card that has specific ground and phono amp specifications and the same thing happens, so I'm assuming the distortion is coming from the turntable itself.

Any suggestions on how to get a clean sound? I have also tried isolating the power plug to reduce/eliminate electrical interference but it doesn't seem to make a difference.

Thanks.