yes i was also present with dalek supreme when this experiment took place .,with the reference 3a de capo and the ecofan pre +ecofan triode 45+triode 6a3 the type 45 valve is the darling of big part of the usa amps and especially the diy people and is an actual audio output valve i think there are about 6 or 8 that i can think of so all the correct boxes were ticked .
it was as dalek described the results
i was planning on putting another step down transformer in my quad electrostat and and be able to bi amp them using the 6a3 and type 45,that was the plan anyway at the time
this 6a3 amp is the best match i have found so far for the quad electrostat but at the moment i have only a small room so i am seriously considering the dulcet the tiny brother of the de capo ,the de capo which i have heard is the only speaker where you could hear very clearly the diffarent sound of diffarent makes of output valves sylvania rca tungsol western electric ken rad ect. i was not able to do this with klipsch horn or the quad 57 the sound is excellent but you can hear small changes but not as instant as the de capo