My New Magnepan 1.7i's sound dull and lifeless on the top end...why?

As most things tech, usually the fixes are simple. When they aren’t simple then it’s a big problem. Just put in the stock jumper and hook up your high watt ss system. Angle the panels so the tweeters are pointed at your listening position. Assuming your fuses are ok, what do you hear? Highs should not be an issue on Maggies. How many watts output are your monoblocks? Maggies like high power. I am using a pair of Bryston 28B3 monoblocks for instance. Schiit Vidars are not enough. I used to run a pair of Vidars and one went into thermal protection. 

+1@ oldhvymec
That makes the most sense!

I have the Maggie's 0.7's ( room won't support 1.7's) for money spent I'm very satisfied with the performance of my Maggie's 
As most know they need watts/current
I tried using my VAC KT88 tube 100 watt amp that has 8,4,2 taps  l also felt l was missing something also on the top end
l decided to try my SS amp that puts out 500watts@8ohm 650@4ohms and 1,200 watts@1ohm +65 amps for 500 milliseconds  I did the fuse, jumper upgrade and Magna Risers speaker stands
All l can is, that it totally transformed my .7's
I position my Maggie's 48" into the room, 110" apart, slight toe in and l have approximately 60" to the side walls l sit 120" from the speakers 
All l can say is now they have excellent inner detail dynamics and nice extended highs

Where along the vertical axis are you measuring?  1.7is and all QR Maggies are only good in the middle one third of their overall height. That’s why 3.7is are so much better… true ribbons do not have that limitation.  

bypass the fuses.