I use E406N single end power amplifiers that I show next above pictures in sub audio system. I built the amplifiers as RE604 single end power amplifier at first, but I felt RE604 is too worthy to use and remade the amplifiers to E406N single end power amplifiers. Until early Autumn 1999, Mazda V312, Dario E406N and Miniwatt 1805 were used for E406N single end power amplifiers, but I found EF37 is better for me than V312 in voltage amplifier and changed tube line up as Miniwatt EF37, Dario E406N and Miniwatt 1805. Although I regarded these amplifiers for experiment as same as AD1 single end amplifiers I wrote above, I think this E406N single end power amplifiers are much enough for sub system and stopped to change any design.
I have another power amplifiers retired from my audio system by appearance AD1 and E406N single end power amplifiers, but I am considering how I use those amplifiers. And, when I look at my power tube collections, I feel my duty of using those tubes as proper.
And Lundahl Transformers are necessary for these Power Amplifiers. I use LL1623 for AD1 Single End, LL1620 for E406N Single End. I believe Lundahl Transformers are best for Audio use at present. If you have any interest in them, please access