Planar ribbon speaker and Tubes Not working Please help!

Hi all, I will try to make this short:
for 2 years I loved my 2 PrimaLuna DiaLogue Premium HP Amps so much that I have invest it in having 3 sets of tubes for them (EL-34, KT-120 and KT-88). I have use them to drive few speakers including a custom open baffle array I make with (12) 7" woofers and 9 BG NEO-8 tweeters each.

Few months ago I auditioned a pair of speakers that blow me away, The latest creation by Greg Takesh of GT Audio Works, a full planar speaker with a large Planar magnetic driver 10" x 72" and a ribbon tweeter .5" x 72".

When I auditioned the speakers they where using PASS XA60.8 amps.

I tried the speakers at home and with the Primalunas the sound is dull, it lack nearly all upper end detail, it sound like I put a 3ohm resistor on the tweeter.

I have a pair of more inexpensive DSonic M3-600 and to my surprise they sound as good as the Pass labs. 

I already tried various cables, all 3 of the amps Tabs 2,4,8 ohm (PL amps are 2,4,8 ohm in mono and 4,8,16 ohm in stereo) and I tried all of my 3 tubes.

The KT120 improved the top end but it is still dull, the EL34 is unbearable (sound like there is no tweeter) 

The speakers are purely resistive (ribbon) 4ohm, 93db.

The only think I have not tried is KT150s and changing the input 12au7 tubes to something like a RCA Cleartop ( I read in the forums those tubes are brighter.

I really need some help, or someone that can really explain why these amps are sounding so bad with these speakers.

I have used these Amps with Joshep Audio, Martin logan, Tyler Acoustics, Magnepan 3.7i plus others and they have always sounded beautiful and always a lot better than my DSonic M3-600, but with this speaker is the exception the Dsonic sound way better than the PL!.

I appreciate any comment/ help etc. At the end if I can make these amps work I will have to find them a good home and get myself a pair of PASS XA60.8.