FlaCharlie
Super Member
This is UL or SET ?View attachment 1175086
It's a little hard to tell what's going on there with all the white goop covering the connections. Not sure why they would do that.
It doesn't look like it's UL. If it was there would be two wires coming from the output transformer to the tube. One to pin 3 (plate) and a separate one to pin 4, which is the screen (G2). UL operation requires a transformer which is built for UL operation and has this special winding.
Technically, the tube itself (EL34) is not a true triode but it can be "triode strapped". If it were wired in triode, pin 3 (plate) would be connected to pin 4 but this is supposed to be done with a 100 ohm resistor, not a direct connection. The goop makes it difficult to tell but they may have just connected the two directly. If so, I'm not sure how much of a problem the missing resistor might be. I think the idea is to keep the screen voltage lower than the plate voltage.