5e3 clone

[danman]

It can be hard to see the filament glow in some preamp tubes but if it is working properly, the tube should feel warm after a minute or two. If not, and you know the wiring is correct and you didn't miss the jumper between pins 4 and 5, it will either be a bad solder joint or a broken wire causing the problem. I stopped twisting my heater wires because it's very easy to break the wire inside if you twist too much.