The ground connection on the back of the KD-500/550 is for grounding the motor and the manual says to use it without fail but that some cartridges will sound fine without it. Same for the ground wire that is part of the tonearm wiring. So bottom line use it if you need it.
Well, yes. That is quite correct. To a an extent. The lug is connected to the motor grounding, that’s common on a lot of tables. That is what he manual says. But real life experience shows if it’s properly grounded, less issues arise.
I actually upgraded the grounding lug on mine, have a massive gold (Monster brand) lug on it now. I run an SME 3009 on mine, I’ve noticed when it was not grounded properly I would get off sounds and my drivers would jump when the stylus hit the LP. The “pop” is something I’ve heard, founding fixed it for me.
It could very well just be that sensitive on his cart/arm combo.
I know it sounds crazy but the best thing I did for mine was oil the motor, it killed any low end rumble and just got dead quite... it on par with my LP 12. If set up correctly they are wonderful decks. Working on tracking down a 650 next.
I know most folks say go to the 750... I’m sure it’s a grand table but I like the stone tables a lot... I’d sale bit linns off prior to letting the kenwood go... just my likes and dislikes I guess