Are these ever converted to a 9 pin 12a*7 socket? Or when you build them, do you typically use the 9 pin instead of the 7 pin socket? What tube do you prefer in v1? I see benefits both ways. I'm used to 12ay7 in V1 on tweed amps and with the 7 pin socket, you only have two choices of tubes to use. While we're on the subject, feel free to show off your 5f10 Harvard or clone and feel free to talk about it. I love reading what you all have to say.