I listen to my homebuilt EL 84 amp everyday. That's my main amp. It sounds good, no matter which amp I find to replace it, I end up going back to this amp. PP EL 84 SS rectified with Dyna output trans. I bought the circuit traced on a PC board, it was beautiful dual trace phenolic board. Then stuffed it and wired it into a chassis. Sounds really nice with the Pi 4's.