Let me start by saying that the SED =C= are very good tubes and were most likely the ones used by c-j to voice your LP 70S.
c-j is currently using the New Sensor Tung-Sol KT120 in their current production amps and the LP 70S should be able to accommodate the higher heater rating. The owners at c-j think very highly of this tube as do most c-j users.
The New Sensor Gold Lion KT88 also comes from the Saratov, Russia factory and is, in my opinion, an excellent choice. I do not find it to be "tubey" sounding although there is an area in the upper midrange/lower treble where I think that 6550-based tubes excel and you may prefer them for that reason.
I do an audio web log for fun and you might want to read some further thoughts on this subject here:
http://jda1951.xanga.com/764150002/new-sensor-gold-lion-kt88/
I've listened to all of these tubes in both a c-j Premier 11A and Premier 140.
Hope this helps a little and good luck in your pursuit.
c-j is currently using the New Sensor Tung-Sol KT120 in their current production amps and the LP 70S should be able to accommodate the higher heater rating. The owners at c-j think very highly of this tube as do most c-j users.
The New Sensor Gold Lion KT88 also comes from the Saratov, Russia factory and is, in my opinion, an excellent choice. I do not find it to be "tubey" sounding although there is an area in the upper midrange/lower treble where I think that 6550-based tubes excel and you may prefer them for that reason.
I do an audio web log for fun and you might want to read some further thoughts on this subject here:
http://jda1951.xanga.com/764150002/new-sensor-gold-lion-kt88/
I've listened to all of these tubes in both a c-j Premier 11A and Premier 140.
Hope this helps a little and good luck in your pursuit.