New KT150 tubes?

Is this an horizontal bi-amped configuration? What's sitting between the 250's?
I would bet that those are indeed 150's.
For room acoustics, they much favour diffusion than absorption in that room.

"Hopefully our government does not start embargoing products shipped from Russia...."

No they won't. Putin will take care of that including shutting down all the oil and gas pipelines heading towards Western Europe creating a global financial collapse.

One bit of hype that seems silly is the claim that the pickle shape eliminates microphonics...assuming this shape doesn't allow vibration from anywhere to get to the tube...nonesense.

More importantly ... do the KT-150s sound better than the KT-120s and if so how much better. Even more important, how much do they cost and is the cost increase worth it.

Bifwynne, Whilst not the sharpest of images when blown up I am pretty confident that they are indeed sporting the Mythical KT150! whether the circuit has been modified in any way is of course unknown.

I am aware of at least two intrepid ARC owners currently running KT150's in their 2x output valve per chanel VSi75's, bias set at 65mv , with no ill effect(as yet)noted.

Again one might theorize that ARC R&D may be a little more confident in respect of KT150 loading on the Mains transformer(s)as supplied on certain of their recent models, they may however be a little less comfortable ,as yet ,in respect of Mains headroom on other models , in particular were a Single Mains transformer is already supplying a Quad of 6550's or KT120's per channel .

Life testing of a new production valve and thorough evaluation of any potential implementation within existent models may take a reassuringly great deal of time .

Mere speculation on my part of course ,In which , as an Ref150 owner I would very much like to be proven wrong !

A great deal of time? How about listening to the amp to see how the tubes sound...that takes about 3 minutes.