Shelter 901 into MM 47k phono stage

Two different tube phono stages I have run my 901 into the 47k mm section I get radio statio RFI that somtimes I can hear the words. It seems to fade in and out and varies from night to night and is quiet in the day time. The other annoyance when oil hot water furnace kicks on and off I get a crack thru speakers to varying degrees of loudness. This happens day or night. If I use the MC stage with set up trans I get none of the above? I hapen to like the sound better into the MM section. I do not want to start any MM vs. MC step up debate.
Any ideas what is going on?
try the mm stage with a high output cartridge and see if the problem is still there. the shelter has a 0.5mv output, and really isn't made to be used with your mm stage.
Thanks Jaybo that is my next step. I have a Grado Sonata I'm going to try.

I have plenty of gain with the MM section. The phono has up to 60db gain and when it's quiet like this morning the sound is real nice with the Shelter.
You might try some type of "power cleaning" device that you plug your preamp/phono stage into. Also see if the noise is present at the same time of day with your cd player