Well, first off thanks so much to all the tdpri community for the incredible support and advice they give This is my first post and although I'm sure my questions have been answered in other posts which I can't find, any help/suggestions would be much appreciated. I finally go's my chassis all wired up (first time ever soldering) except for the ground bus on the left side. I used the boothill wiring diagram, as well as robrobs 5E3 deluxe amplifier one from his website. My biggest confusion now is exactly how to ground the power transformer, and where the ground bus for the left side of the circuit board hooks up too. I think I understand how the output transformer. There is also a mysterious 3 prong price that I haven't seen pictures of or diagrams of anywhere, I feel like it has something to do with the grounding, but any pictures or information would be much appreciated. I have no clue where it goes or what it hooks onto, so I will attach a picture of it. Again Thanks so much, I'm just a 20 year old building an amp for the first time with little knowledge about electronics, but a love for tube amplifiers.