ARC switched most of its tube amps over to the KT-120 in November 2010. Previously, the 6550 "Winged C" was the tube de jure. My previous ARC amp was the VS-115, which came standard with the 6550Cs. I dropped in KT-120s a soon as ARC cleared the new tube.
At least as far as my VS-115 amp was concerned power output increased from 115 wpc to 128 wpc. Sonically, IMO, the KT-120s cleaned the floor with the 6550Cs. Better headroom, dynamics, bass, etc.
At least as far as my VS-115 amp was concerned power output increased from 115 wpc to 128 wpc. Sonically, IMO, the KT-120s cleaned the floor with the 6550Cs. Better headroom, dynamics, bass, etc.