Last night I received some NOS 6FD7 (Big Bottles) from Woo and paired them with the SP-274B (which most don't care for) and I must say, with my WA6/RS1i this combo sounds the fullest/richest just with slightly less detail/sound-stage, but has more the 6FD7's have more power than any of my other power/driver tubes, and I'm really enjoying it! One thing though…my transformer was humming/buzzing last night and the amp runs warmer than usual, so I cleaned all the pins with Deoxit on all of the tubes and put them back in a little while ago, and initially still had noise but only for a short time…now I'm glad to say the transformer is dead silent.
Regardless of what others may say about the SP-274B I think it is a nice sounding rectifier tube with the right power/driver tubes and the RS1i.
Regardless of what others may say about the SP-274B I think it is a nice sounding rectifier tube with the right power/driver tubes and the RS1i.