ESL electrical tingling sensation

[dmimis1]

Hi... Today I noticed this weird problem with my Electromotions. I was cleaning my rack and had everything disconnected from my power amp. The first thing I connected was the speakers. When I connected them I felt an electrical tingling sensation when touching the faceplate of the amp. Something similar to the sensation given on a macbook laptop when only the 2 pin plug is used. (there must be someone who has felt this - it's notorious). Nothing else was plugged on the amp. I then connected the mains, but the sensation remained. It only stopped when I connected the 1st of the 2 XLR inputs. So I am guessing some grounding issue. Current passed on from speaker through the speaker cable? Is this normal??