Jadis ja-200 vs ja500

Thank you, guys. Very good comments, just what I was looking for. 
Rcprince, the JA30 is indeed a wonderful amp. I tried it with kt88 and El 34. It sounds amazing on my quad 57 (for those looking for a good match with those), but on my ESP Bodhran, you hear it is getting stressed at times. Besides, I have preference for powerful amps. Even when I owned the Klipsch La Scala with its very high sensitivity, I always liked it better driven by many tube watts (well, actually it was my wife who set the tone here). Smaller amps can have higher resolution but they always lack, for me at least, the sense of ease that big amps have, which is more like the real thing for me.
Cheers.     

Well, not sure about the sensitivity and impedance figures for the ESPs (their website has no information about their models, from what I can see), but I'd say if you want that sense of ease the 500s might be your ticket.  When I heard them they were driving mbl 101s (the original model) with no strain, so I'd say they could drive just about anything.  But, despite not being pure class A, they will throw off more heat than the 200s, simply from the larger number of tubes in them.  The setup with the mbls had the 500s in a separate room to keep the heat down in the listening room. 

@taviran I would consider the JA80Mk2. Not going to be a heat engine like the other amps up the line (200 and 500) and will give you the ability to hear the new KT150’s along with auto biasing and enough power to drive your speakers. IME, the best sounding Jadis amps are the middle to low power models. If you can get away with less power, consider the JA30Mk2.( more power than your current older version JA30).

well my Defy7 is out of commision at the moment,,I did some things the Defy is not at all happy about and so shut down,, 
Returned the new SVETLANA 6550's w/o hearing them, as i took my tech guy here in New Orleans advice , which he suggested in  look into the Gold Lion KT88's. 
after hearinga  YT vid with GL 88's, WOW, what a  stunning sound. 
So retured the 6550's witha a  $100 restock fee added on to VIVATUBES order,,and  once return is completed will order 12 perfectly matched 12 (4 sets of trios) from Vivatubes.
also asked randy to see about swapping some resistors , will go with RIKEN Resistors, as they have copper leads, others have aluminum leads. 
Just the fact this lab uses copper as leads lets me know they alos put attention in the actual resistor as well.
Won't change them all, as its about 50 resistors. 
Just the critical ones.
Right now amp is out of commision, both channels.
also wish to say this Defy's trans run slightly warm center and 2 side trans, run cool/cold.
Tubes put out somer heat, but nothing excessive, as i placed a  window unit in my room, and on hot days , will run it  all  night with door closed, so in the morning for listening,, the walls/room is ice cold,,and ready for 4 hours of listening,,when i break for breakfast, i will shut system down and restart window unit.
I can always start up central air, But really heat is not that much ofa  issue,,Now witha  JA200/500, with 24+ tubes, yeah I can see heat would bea  issue. What i would suggest is have your handy man install a bath vent in ceiling to suck hot air out  through attic vent. But then you have the vent running noise,, so not a  option,, How about  makinga  hole in ceiling, and placing a  tiny fan in attc, over the hole, you will not hear fan run. This to me is the best option. 

Update: Bought old Jadis JP80 and connected it to the JA30. WOW! Right now I feel no need for a bigger Jadis amp. Amazing resolution, depth, bass, dynamics, emotion. So it seems like the problem was in the preamp, not the amps.  Thanks for all responders.