Requesting input on preamp schematic

[A3rd.Zero]

Well I feel sheepish.

For some reason I swapped the plate resistor and the grid leak resistor. And forgot to add the grid leak resistor. 😱

Sounds much better now. Still a fair bit of hum but I expected that. Sure is a nice sounding little amp.

 

[A3rd.Zero]

Going to try and re-bias the 12au7 to 3V with a 33k plate resistor, and a 1k bias resistor. Also bumping the grid leak resistor to 1M.