Blown Tweeter & midrange fuses Magnepan 3.6r

My problem is I keep blowing the tweeter fuses at a "somewhat" moderate volume. I inititially owned the Yamaha RV-1103 Surround Receiver and blew both the tweeter fuses at somewhere around 2/3 - 3/4 volume potentiometer setting. I heard that these speakers require a lot of high current. Many people drive these with 40 wpc mono-blocks in a good size room and don't complain of blown fuses.

I purchased a Krell HEAT (Showcase) system (125 wpc @ 8 ohm, doubling to 250 wpc a (Magnepan rated) 4 ohm load. I still have the same problem. In fact I have even blown the 5amp midrange fuses. The maximum power level on the Krell digital amplifier is 100). I set the level at 40 and still blow the tweeter fuses in both channels simultaneously. I have never heard any audible cliipping during these times, however, my hearing rolls off at 14 KHZ. I have had two different KRELL HEAT (Showcase) amplifiers driving them, with same results. I have an open floor plan 20' x 15' listening area and the volume levels are no where near ear-piercing levels. I'm beginning to think I purchased defective speakers. Can you help me?
What do you think ?