When I had the Dyn C1 sig's I loved the Mullard CV4024 and Telefunken 5965's especially with original Tung Sol 6550 solid black plates. I also liked the RCA 5751 triple mica black plate in place of the 12ax7 (another nice warm sound). I really hated the TS KT120's (very forward and in your face but punchy). Other Octave/Dynaudio owners agreed. Well that all changed when I upgraded to the Raidho D1's. Now the KT120's sound great and the Ei KT90 type 2 sounds the best. Honestly the Ei KT90's sound great with either speaker.