Thanks everyone for the information. Since my original 5U4G is basically new, I've just ordered another one will use both in my WA5.
@elliottbnewcombjr , interesting that you noticed a difference in sound from the rectifier. I've read mixed reactions how the rectifiers affect the sound. I wonder how much the transformers in different ams/preamps affects the rectifier tube making a difference in sound?
@ghdprentice , thank you. I am fortunate and happy to be able to have it. One of the things I like about it is the versatility with impedance and power options. The Auris Nirvana was my other choice. I sold my LTA Z10i which has been my favorite headphone amp to date. I haven't spent a lot of time with it yet, so reserving final thoughts until I listen more and upgrade tubes. Besides the Ray rectifier tubes, I have just installed Ray Reserve 6SN7's for drivers. Thank you for the Takatsuki recommendation. After research and knowing the type of music I listen to most, I think I'm going to find either the Audio Note 4300e or the EML 300b. The Takatsuki and the Elrog are a little more than I want to spend right now.