Was really trying to avoid posting for help but this has me totally stumped! I've been firing up my (metro spec) JTM45 clone for the 1st time. After investigating a very low/weak output I tracked it down to the phase inverter (V3). The PI is only outputting ~1V pk-pk and only on the RIGHT-hand triode (pins 1-3). The left-hand triode isn't outputting anything. I've tried isolating the PI by pulling all the other tubes (except the rectifier) and it still behaves the same with a test signal injected directly onto the left-hand grid. Ive also tried swapping out for a different 12AX7. Ive checked and double checked the components and they seem to be correct. I've also measured the resistance of the grids & cathodes to ground and get exactly the values I expect based on the schematic. Here is the schematic for reference: Here are my voltages. Note how the plate of the left-hand triode (pins 6-8) is at ~ full B+, and the right-hand side is at a more expected voltage. I have double checked that the pin is wired to the correct node. Also the grid voltages are different between each triode and I would have expected them to be the same: Here is a pic of the board. Note the NFB has been disconnected eliminate it as a cause: Any clues in there? Something else I could check? I really hope im missing something really basic and stupid.