Is ground noise really normal? If so, why?

'Ground noise' sounds like a bad ground connection to me.
If you have a balanced preamp then the ground of the arm should also be the shields of the tone arm interconnect cable and tying to pin 1 of the XLR connections on your preamp. The '+' and '-' outputs of the cartridge then connection to pins 2 and 3 of the XLR input connectors.

Ralph, First we need to determine if the OP is truly experiencing noise due to bad grounding.  I'm not sure.  But in balanced mode, I've never had any audible grounding issue, no matter how sloppy I might be with grounding the tonearm or turntable or etc.

As others have alluded to the OP should clarify what he means by "ground noise." Hum? Hiss? Something else? Is it present only when the stylus is in the groove of a rotating record, or is it also present when the stylus is lifted off of the record? Or is it present even when the platter is not rotating and the turntable is turned off?

Also, what cartridge is being used, and what gain and input impedance is the phono stage set to? For example, if the cartridge is a moving magnet type and the input impedance is set to 100 or 1000 ohms (the two choices that are provided in addition to the 47K setting that should be used for moving magnet cartridges) it would certainly result in poor signal-to-noise ratio.

But to provide a preliminary answer to the initial question, I would not expect an Ayre phono stage to have objectionable noise levels unless there is something is wrong in the setup or the unit is defective.

Regards,
-- Al

My system is dead quiet..even on phono...I have an all Ayre system with Vandersteen 5A's

Alas, my tone arm is not balanced as I didn’t know it was an option. So while the P5XE feeds the rest of my stack in balanced mode, the tonearm wiring is good old hummy. I’ve to a spool of low voltage wire on the way (remember how great it was to have old radio shack around for that sort of thing?), maybe I can get rid of the noise by grounding the chassis in a few more spots,