phono hum

I have a stock Thorens 146 with a Luxman SQ-30U integrated amp. The TT and amp are sitting at the same level in my cabinet separated by only a 3/4 inch wood partition. So they are only 2-3 inches apart. I have a hum in both speakers when the volume is turned up close to normal listening level (30%). Hum increases with volume. As the tonearm moves toward the spindle (further away from the amp) the hum decreases. Phono cart is Signet TK5E. If I mount a Shure M97x the hum is less. I do not recall the hum when I had a Denon DL-110. The Signet is the best sounding of the 3. It appears that there is interference from the amp. Is there a way to block this interference? More wood, metal, or just more distance between the 2? Or, do I need to stay with MC carts? Any recommendations for MC carts? Thanks Tim