O'Kay; hold off it is. But out of curiosity why after all this time of speculating about large high voltage triodes do you settle on trying this particular circuit? Did you hear one you really liked? Or is this a way of getting something started? I for one have always been tentative around the CCS only because if the transistor should fail the amp is in big trouble. And transistors fail around high heat conditions; no? Also since they require bias that potential for drift is constant right. Anyway I am enthused about building this or something now; maybe Damir can take this ride with us also. And Colin. I would like to see a group purchase of chassis. I am not a big fan of top mounted input and speaker jacks. There are some new chassis companies out there so the price is easing up a bit. But there must be a company like Heybeor that does this chassis work. Or maybe some metal work place would bend up some sheet stock.