KLH model 9 electrostatic Speakers

"Will Dynaco st 70 watt good enough power for the nines?"

Depends on how loud you listen. I would love to hear the 9's with something like a Pass XA 60.8. Parasound JC 1+ would be overkill. 
I am not familiar with the Plinius amp but if it sound fine stick with it. It is a 100 watt/ch Class A amp which in my experience should be more than enough. If it sounds anything like my old Krell KMA 100's you should be in hog heaven.

Ralph and Myjostin , I agree to both of you. Thanks

I tried my MIT Speaker Cable with a box , I think it’s the s3 , there is no sound coming out from KLH.

I connected my MIT speaker cables with a box to my KLH , no sound came out. The mit works on my other non electrostatic speakers, I wonder why..

I agree mijostyn! After many years with cones and domes planar magnetic the ESL treble is most like live instruments. Trumpet, violin, saxophone etc. I recently picked up the motion ESL by Martin Logan at a great price. Even that little speaker has truth of timbre a $100k speaker couldn't match. I know ML it's not perfect ( slightly lean sound) but what it does well is SOTA!