Thursday, June 2, 2022

"Koto" - 12AU7/6AS7 SET amplifier


 






















Still on a roll to use expensive parts, stored away for many years in store room, here is a 6AS7 SET amp. Its been many years since I've built one of these. I remember being impressed with my first which sold quickly. I had the Edcor power tranni, Edcor 1.7K OPTs and expensive Jensen copper, paper and oil inter-stage caps, new 5Y3GT rec. tube, base and ABS top plate plus and tube sockets. No excuse not to build a two-stage SET.

Apart from NP caps as cathode bi-pass and Cat5 wiring throughout there is nothing else exotic in parts. The PS once more is double Pi - CRCRC - with 5Y3 tube rectification and further filtering at the driver stage. 6AS7 is a well used RCA but a new Genalex Gold Lion 12AU7 was used as the driver tube. The sound is open, detailed with depth and wide sound stage. Bass extends well. Only a few watts but in my system enough. Also pictured here is my EL34/KT88 SE UL amp with KT88s installed. I could happily live with either.