The best  triode of it's kind, is by no doubt Telefunken ECC803S.   I have no numbers available, but I know first hand from an ex TFK employee living in Ulm, only very few of those were ever made. So you can stop searching for those sleeping lots in old warehouses : That never existed. He told me, the initial buyer was an equipment company Wandel & Golterman in Germany. For them this tube was constructed, for their test equipment. I know this company, I have visited them several times, for other reasons in 1990. Sure I can say, they were small by then, and they must have been even smaller in 1960 when ECC803S was made specially for them only. Realistically speaking, today most of that equipment is destroyed now. So finding ECC803S has very low chances.

Later, Telefunken sold the ECC803S on the market. Any HiFi purpose was not intended, and the tube was too expensive from the beginning. So things stayed as they are, very few were made, and it is the remains of those few that we are all looking for. So a large demand, and no supply. That explains the price. Technologically, the tube is superb. TFK ECC803S has lowest noise, lowest microphonics, at high gain, and a balanced and matched tube out of the box. It is matched so well that two random tubes, you put them together and you have a matched pair. And all of that is guaranteed for 10.000 hours. And they means with that not maximum 10.000 hours, but minimum.

So the say TFK ECC803S, it is the ideal tube. Well.... it is indeed, but prices are crazy. I have seen them for 1200 Euro already, while I write this in 2011, and this doesn't seem the limit.

подскажите как можно проверить не подключая в ламповый прибор хотя бы бегло исправность лампы?
у меня есть 8 штук 6н2п-ев. одна из них имеет посеревший геттер я думаю ей сто процентов хана. там или вакуума нет или она отработанная совершенно

какие еще есть признаки что можно было бы мультиметром или еще как-то проверить?

Самое просто вставить в собранный усилитель. Ах да.....не тот случай.

Вы мне дали рисунок платы для питания.
Может быть у вас найдется в каком-то другом формате - не рисунка, чтобы там можно было его 1 к 1 для травления печатать?
На изображении, которое вы разместили, не могу понять какие у платы физические размеры

вы тут сами вроде риторически спрашиваете сами отвечаете...тихо сам с собою.....