Rega hum


Rotel RC-1090 pre
Rotel RB-1092 amp
Rega P5, TT PSU, Exact cartridge.

Noticed this weekend an annoying hum in the background especially with nothing playing on the TT and volume up. What do I need to do to rid this hum? I realize Regas are grounded internally. BTW, table is completely stock. All equipment is plugged into a Rotel RC-1040 power conditioner. Thanks for all suggestion.
miner42
All RCAs were tight - no lamp on nearby but I do have a ceiling light that is on a dimmer switch. Light was not on though during play. By internal ground I mean that is the way the Regas are designed. There is an internal ground wire within the tonearm and I believed grounded to one of the RCAs. I was told by the Rega US distrubutor that there will be some hum until the coils in the cartridge are put to use (when stylus sets down on LP). Maybe I am being too anal about my vinyl rig. He also suggested unplugging TT PSU from power conditioner and plugging directly into the wall. I don't like that idea.

How would I externally ground a rega table?
Any other ideas? I have plugged the TT PSU into the wall outlet - no change, still hums. I am looking for dead silence when phono is selected on my pre (Rotel RC-1090) and no LP playing. This is when I notice the hum the most. I am at my wits end. Am I asking too much for silence through the phono stage? I am using a MM cartridge.
How far away is the pre from the power? The preamp phono section could be picking up hum from a nearby transformer.
Hello Miner42:
I had a P3 that had the same problem. Rega's response was the same. When the LP is playing there is much less hum. I was using a Jolida JD-9 phone stage (tubes) and I found with an upgraded power cord (LAT International AC-2) the hum was much less. I also noticed that once I gave up on trying to get rid of it, it mostly went away. Perhaps one of those audio mysteries like cable break-in. Once everything settled in it was much better. I'm using a Rega RB1000 arm on an LP12 with a Graham Slee Reflex phone pre and it's dead quiet. Maybe the upgraded cables in the RB1000 make a difference or maybe it's the preamp.

Have a little patience and perhaps it will improve.
Headsnappin

My Pre is one shelf above my power amp - a Rotel RB-1092 - about 2.5" from top of power amp to bottom of pre separated by .75" of oak.

Arch7,
If I were to upgrade my power cord should I upgrade the pre or the amp power cord? The power cord to my TT PSU is not detachable.

Thanks to all who have submitted their opinion.