The Grados have a pretty sketchy reputation of excess noise or hum with many tone arms and setups in general. If you can get it right they are suppose to be really good for the money, but if your getting noise from a grado its supposedly very hard to go the other direction from my understanding. I own that table, with KAB everything as well, its dead silent.
I have owned grado, had them in the past and they were noisier, however never heard them on this table. I would borrow another cart first and see what it does electrically being hooked up into the signal first, you don't even have to set it up, just mount another cart to a new headshell and mount it to the arm connect the headshell wires. See if the noise is gone then its the grado having an issue, load, acoustic arm resonance whatever.
By the way I currently have a .4 mV moving coil myself on that table combo, works silent, so its nothting to do with low output specifically, but possibly that cart. directly.
Good luck
I have owned grado, had them in the past and they were noisier, however never heard them on this table. I would borrow another cart first and see what it does electrically being hooked up into the signal first, you don't even have to set it up, just mount another cart to a new headshell and mount it to the arm connect the headshell wires. See if the noise is gone then its the grado having an issue, load, acoustic arm resonance whatever.
By the way I currently have a .4 mV moving coil myself on that table combo, works silent, so its nothting to do with low output specifically, but possibly that cart. directly.
Good luck