I used the out put transformer from au111 Sansui tube amp .every body can order new type from hashimito by 600 $ . power supply is important point in project .for best sound I used German Siemens 5ar4 rectifier (maybe amperex original made ).another the filament providing current . I made single ended 6b4g that sound was nice too. If you want the grate sound in your lessening room I promised you that the 6b4g is good chose .