Hum coming from setup of Phon pre and turntable

Ideas? All other units (amp, pre, cd transport, etc are quiet.) Hooked up my Oracle TT the other day with new Phone pre-Conrad Johnson--when phono is on--loud hum coming through speakers- chassis on TT is grounded to phone pre--

Thoughts---I have eliminated all power cords "grounding" pin with adapter as suggested. No improvement.

Thanks-((I realize this can be very complicated.--but I thought someone might have a checklist from start to wherever--thanks--
was there preamp before new CJ?
did you check cartridge clips in place tight?
are they properly connected?
You need to list all of your components.
Is your phono cable shielded?

Yes -Pre Amp in place for the last few years. CJ ET5-- not sure on question re cartridge clips-was installed on Oracle when I had Oracle cleaned, adjusted etc.
other components are 250S CJ power Amp--Romulus CD--

does Turntable need to be grounded to Phone Pre--or should both be indecently grounded to amp etc? or does that matter?
i'm not sure if phonostage uses tubes. if yes than you should check them. if buzz in both channels check only with spear healthy tubes. i think you should id them with manufacturer or with manual.
phonostage, does have tubes.
Can you list your entire system?