Connecting the ground wire makes music less lively


Friends,
Lately for some strange reason I heard hum from my TT setup. When I connected the tonearm ground wire to the phono the hum was gone. Thats the good news. The bad news is, when I heard the music with the ground wire connected, it sounded less lively, less palpable. Some vitality was taken away. When I remove the ground wire the life in the music is again back, just that the background hum is audible during silent passages (thats irritating). Has anyone else heard this effect ? Is there a solution to this problem ?

My phono stage is very heavy and can't be moved around. I have to say this problem is quite disturbing because either way there seem to be a serious compromise which is not really the fault of the components.
pani
try to look at the Garrard ground...it is usually just 2 prong cable. The ground should be from the motor bracket. That may help with the hum...the liveliness may be some combination between these two grounds....
What should I exactly do to the Garrard ground ?
Should I connect a cable from the motor bracket to the ground of the AC mains ?
I tried borrowing a friend's pro-ject phono stage which has variable gain options. I noticed that with this phono there is no hum at 40 db and 50 db gain, however the moment I switch the gain to 60 db (that is the max gain on this phono) the hum is back. Can this be used as a clue ?
Atmasphere, this hum issue is a recent one. It did not happen before. The cables were no different. Moreover the Mogami 2549 and 2534 cables that I use are extremely low capacitance cables. I also have a Van Den Hul D501 phono IC which also doesn't solve the problem.
Another observation: I noticed that when I switch off the motor of my Garrard 301 the hum changes. It becomes thinner and slightly less prominent. Does that mean it is something to do with the Garrard motor grounding ?